subject:(Quantum)

University of Illinois – Urbana-Champaign

1. Banerjee, Tuseeta. Path integral methods for quantum dynamics in condensed phases.

Degree: PhD, Chemistry, 2015, University of Illinois – Urbana-Champaign

► Quantum mechanical effects play an important role in dynamics of condensed phases. It is also well known that the difficulty of solving the full Schrödinger… (more)

▼ Quantum mechanical effects play an important role in dynamics of condensed phases. It is also well known that the difficulty of solving the full Schrödinger equation grows exponentially with time. One approach to cope up with this difficulty is to restrict quantum treatment to a few particles (system) and treat the dynamics of the rest of particles (bath) using classical trajectories. Path integral methods due to their trajectory like nature provide excellent tool to develop quantum-classical methods, but to capture long time dynamics, the number of classical trajectories grow exponentially. A part of this work focuses on improving Quantum-Classical Path Integral (QCPI) treatments that allow for larger path integral time step by building “smarter” propagators. These improved solvent-driven reference propagators is developed by incorporating physically motivated approximations to the solvent. When used in QCPI expression they allow convergence with larger time steps leading to an exponential reduction of the number of trajectories required. Further advantages of these propagators include improvements in path filtering techniques, smaller number of path integral steps for achieving the memory decoherence time, and smoothing of the integrand which leads to convergence with fewer Monte Carlo sample points. These ideas have been validated on the spin boson model - a prototypical model to study condensed phase dynamics, which consists of a two-level system coupled to a harmonic bath. The new approach of building the reference propagators combined with their iterative evaluation and filtering is validated using parameters that mimic the first electron transfer in wild-type photosynthetic reaction centres. A real-world dynamical simulation contains various anharmonic effects, Ferrocene (donor) - Ferrocenium (acceptor) system in liquid Benzene was studied where the anharmonic effects of the bath of liquid Benzene on the dynamics of the system were treated using Ensemble Averaged Classical Path. The process of electron or proton transfer occurs between two species having different charges and fluctuations in the solvent plays a key role in determining the rates of such reaction dynamics. To correctly account for the effects of initial distribution of the solvent on the dynamics of the quantum system, the concept of equilibrating the bath to the donor state of the system is used. Two different approaches have been used within the influence functional framework. Advisors/Committee Members: Makri, Nancy (advisor), Makri, Nancy (Committee Chair), Hirata, So (committee member), Luthey-Schulten, Zan (committee member), Schweizer, Kenneth (committee member).

Subjects/Keywords: quantum

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APA (6^th Edition):

Banerjee, T. (2015). Path integral methods for quantum dynamics in condensed phases. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/89036

Chicago Manual of Style (16^th Edition):

Banerjee, Tuseeta. “Path integral methods for quantum dynamics in condensed phases.” 2015. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed February 28, 2020. http://hdl.handle.net/2142/89036.

MLA Handbook (7^th Edition):

Banerjee, Tuseeta. “Path integral methods for quantum dynamics in condensed phases.” 2015. Web. 28 Feb 2020.

Vancouver:

Banerjee T. Path integral methods for quantum dynamics in condensed phases. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2015. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/2142/89036.

Council of Science Editors:

Banerjee T. Path integral methods for quantum dynamics in condensed phases. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/89036

2. Bouchard, Frédéric. Quantum Cryptography Beyond Qubits .

Degree: 2019, University of Ottawa

URL: http://hdl.handle.net/10393/39731

► Over the last few decades, quantum cryptography has been one of the most important quantum technologies developed. It holds the promise of communicating secure information… (more)

▼ Over the last few decades, quantum cryptography has been one of the most important quantum technologies developed. It holds the promise of communicating secure information over untrusted channels. In particular, quantum cryptography is immune to the eventual threats posed by large-scale quantum computers, which is not the case for our current classical cryptography infrastructures. In a world where information, communication and privacy are of paramount importance, the development of secure quantum communication infrastructures becomes imperative. So far, most of the quantum cryptographic systems developed to date are based on two-dimensional encoding schemes, analogous to classical bits, known as qubits. Nevertheless, other than for the polarization of light, photonic degrees of freedom, i.e. position, momentum, time and frequency, naturally occur as high-dimensional quantum systems. Moreover, by considering high-dimensional encoding schemes beyond qubits, advantages in terms of information capacity and noise tolerance are predicted in theory. In this thesis, the basic components of a high-dimensional quantum cryptographic system are investigated. We begin by reviewing important developments in quantum cryptography and high-dimensional quantum information. As a starting point, two different quantum information tasks, i.e. optimal quantum cloning and quantum metrology, are experimentally investigated for high-dimensional quantum systems in order to demonstrate the numerous advantages of performing quantum tasks beyond qubits. The photonic degree of freedom used in these experiments, known as transverse spatial modes, is obtained by combining the position and momentum photonics degrees of freedom. Thus, we develop a novel method to measure high-dimensional quantum states encoded in arbitrary spatial modes. Using a similar characterization technique, several high-dimensional quantum communication channels are characterized to perform high-dimensional quantum cryptography. The tools developed in the laboratory are then brought to realistic conditions in order to test the feasibility of high-dimensional quantum cryptography. Two different types of quantum channels are experimentally investigated, namely an intra-city 300 m long free-space link and a short 3 m outdoor underwater link. Finally, we investigate and compare novel high-dimensional protocols to overcome current limitations.

Subjects/Keywords: Quantum

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APA (6^th Edition):

Bouchard, F. (2019). Quantum Cryptography Beyond Qubits . (Thesis). University of Ottawa. Retrieved from http://hdl.handle.net/10393/39731

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Bouchard, Frédéric. “Quantum Cryptography Beyond Qubits .” 2019. Thesis, University of Ottawa. Accessed February 28, 2020. http://hdl.handle.net/10393/39731.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Bouchard, Frédéric. “Quantum Cryptography Beyond Qubits .” 2019. Web. 28 Feb 2020.

Vancouver:

Bouchard F. Quantum Cryptography Beyond Qubits . [Internet] [Thesis]. University of Ottawa; 2019. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/10393/39731.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Bouchard F. Quantum Cryptography Beyond Qubits . [Thesis]. University of Ottawa; 2019. Available from: http://hdl.handle.net/10393/39731

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of New Mexico

3. Cesare, Christopher. Topological Code Architectures for Quantum Computation.

Degree: Physics & Astronomy, 2014, University of New Mexico

URL: http://hdl.handle.net/1928/24543

► This dissertation is concerned with quantum computation using many-body quantum systems encoded in topological codes. The interest in these topological systems has increased in recent… (more)

Subjects/Keywords: physics; quantum; quantum computing; quantum memory

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APA (6^th Edition):

Cesare, C. (2014). Topological Code Architectures for Quantum Computation. (Doctoral Dissertation). University of New Mexico. Retrieved from http://hdl.handle.net/1928/24543

Chicago Manual of Style (16^th Edition):

Cesare, Christopher. “Topological Code Architectures for Quantum Computation.” 2014. Doctoral Dissertation, University of New Mexico. Accessed February 28, 2020. http://hdl.handle.net/1928/24543.

MLA Handbook (7^th Edition):

Cesare, Christopher. “Topological Code Architectures for Quantum Computation.” 2014. Web. 28 Feb 2020.

Vancouver:

Cesare C. Topological Code Architectures for Quantum Computation. [Internet] [Doctoral dissertation]. University of New Mexico; 2014. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/1928/24543.

Council of Science Editors:

Cesare C. Topological Code Architectures for Quantum Computation. [Doctoral Dissertation]. University of New Mexico; 2014. Available from: http://hdl.handle.net/1928/24543

University of New Mexico

4. Madhok, Vaibhav. Quantum correlations, chaos and information.

Degree: Physics & Astronomy, 2012, University of New Mexico

URL: http://hdl.handle.net/1928/21057

► Quantum chaos is the study of quantum systems whose classical description is chaotic. How does chaos manifest itself in the quantum world? In this spirit,… (more)

▼ Quantum chaos is the study of quantum systems whose classical description is chaotic. How does chaos manifest itself in the quantum world? In this spirit, we study the dynamical generation of entanglement as a signature of chaos in a system of periodically kicked coupled-tops, where chaos and entanglement arise from the same physical mechanism. The long-time entanglement as a function of the position of an initially localized wave packet very closely correlates with the classical phase space surface of section – it is nearly uniform in the chaotic sea, and reproduces the detailed structure of the regular islands. The uniform value in the chaotic sea is explained by the random state conjecture. As classically chaotic dynamics take localized distributions in phase space to random distributions, quantized versions take localized coherent states to pseudo-random states in Hilbert space. Such random states are highly entangled, with an average value near that of the maximally entangled state. For a map with global chaos, we derive that value based on new analytic results for the entropy of random states. For a mixed phase space, we use the Percival conjecture to identify a "chaotic subspace" of the Hilbert space. The typical entanglement, averaged over the unitarily invariant Haar measure in this subspace, agrees with the long-time averaged entanglement for initial states in the chaotic sea. In all cases the dynamically generated entanglement is that of a random complex vector, even though the system is time-reversal invariant, and the Floquet operator is a member of the circular orthogonal ensemble. Continuing on our journey to find the footprints of chaos in the quantum world, we explore quantum signatures of classical chaos by studying the rate of information gain in quantum tomography. The measurement record is obtained as a sequence of expectation values of a Hermitian operator evolving under repeated application of the Floquet operator of the quantum kicked top on a large ensemble of identical systems. We find an increase in the rate of information gain and hence higher fidelities in the process when the Floquet maps employed increase in chaoticity. We make predictions for the information gain using random matrix theory in the fully chaotic regime and show a remarkable agreement between the two. Finally we discuss how this approach can be used in general as a benchmark for information gain in an experimental implementation based on nonlinear dynamics of atomic spins measured weakly by the Faraday rotation of a laser probe. The last part of this thesis is devoted to the study of the nature of quantum correlations themselves. Quantum correlations are at the heart of the weirdness of quantum mechanics and at the same time serve as a resource for the potential benefits quantum information processing might provide. For example, Einstein described quantum entanglement as "spooky action at a distance" ~. However, even entanglement does not fully capture the complete quantum character of a… Advisors/Committee Members: Deutsch, Ivan, Prasad, Sudhakar, Finley, Daniel, Ghose, Shohini.

Subjects/Keywords: Quantum chaos; Quantum entanglement; Quantum computers.

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APA (6^th Edition):

Madhok, V. (2012). Quantum correlations, chaos and information. (Doctoral Dissertation). University of New Mexico. Retrieved from http://hdl.handle.net/1928/21057

Chicago Manual of Style (16^th Edition):

Madhok, Vaibhav. “Quantum correlations, chaos and information.” 2012. Doctoral Dissertation, University of New Mexico. Accessed February 28, 2020. http://hdl.handle.net/1928/21057.

MLA Handbook (7^th Edition):

Madhok, Vaibhav. “Quantum correlations, chaos and information.” 2012. Web. 28 Feb 2020.

Vancouver:

Madhok V. Quantum correlations, chaos and information. [Internet] [Doctoral dissertation]. University of New Mexico; 2012. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/1928/21057.

Council of Science Editors:

Madhok V. Quantum correlations, chaos and information. [Doctoral Dissertation]. University of New Mexico; 2012. Available from: http://hdl.handle.net/1928/21057

Macquarie University

5. Javaherian, Clara. Quantum transport and switching in long-range coupled quantum systems.

Degree: 2016, Macquarie University

URL: http://hdl.handle.net/1959.14/1249385

►

Thesis by publication.

Bibliography: pages 89-97.

1. Introduction – Efficient quantum transport in qubit networks – 3. Geometrical robustness of qubit networks – 4. Switching… (more)

▼

Thesis by publication.

Bibliography: pages 89-97.

1. Introduction – Efficient quantum transport in qubit networks – 3. Geometrical robustness of qubit networks – 4. Switching application of qubit networks – 5. Conclusion.

Controlling the dynamics of quantum states is a common demand in quantum technology. We theoretically study quantum transport and switching in long-range coupled quantum networks possessing a single excitation. The qubit networks of our study are affected by Markovian environments while one qubit is irreversibly connected to an additional site. Different goals are studied towards controlling quantum transport such as efficient single excitation transfer, switching quantum transport,and manipulating the quantum states of qubit networks. These goals have been previously investigated using different mechanisms, however in this thesis we approach them by proposing appropriate geometrical arrangements of sites.

Regarding efficient single excitation transfer we follow two approaches: Checking if there exist a spatial dimension preference for qubit arrangements towards optimal quantum transport, and whether the efficient network designs are robust against geometrical variations. For dimension analysis a random walk optimization method is used to compare the transport efficiency of networks expanded in one and two spatial dimensions. We find that for some choices of network parameters the two-dimensional networks are slightly more efficient than the one dimensional equivalent networks. This assures that designing one-dimensional qubit channels are adequate for efficient transport and the two-dimensional networks should only be considered where the two-dimensional spatial expansion is more compatible with the surrounding architecture. To design a network, after deciding about the network dimensionality, one may attempt to optimize the channel geometry which might result in a non-robust optimal configuration against the geometrical errors.

To achieve robust optimal configurations we follow two approaches: We investigate the efficient configurations of sites in both one and two dimensional arrangements and present some patterns of robust geometric arrangements of sites in geometrical parameter space. Another approach to achieve robust efficient transport is defining a quantity as the geometrical robustness (georobustness) of qubit networks. By optimising geo-robustness against the network-environment parameters one can efficiently transfer a single excitation with many arbitrary arrangements of the network sites.

Switching of quantum states is another goal towards controlled quantum dynamics. We study the transport characteristics of highly symmetric three-dimensional networks and analytically prove that a fraction of the initially injected excitation can trap for long durations via the creation of dark states. Using this characteristic we suggest switching devices which are robust against environmental noises.

1 online resource (xxxii, 97 pages) illustrations (some colour)

Advisors/Committee Members: Macquarie University. Department of Physics and Astronomy.

Subjects/Keywords: Quantum systems; Quantum theory; quantum transport; switching

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APA (6^th Edition):

Javaherian, C. (2016). Quantum transport and switching in long-range coupled quantum systems. (Doctoral Dissertation). Macquarie University. Retrieved from http://hdl.handle.net/1959.14/1249385

Chicago Manual of Style (16^th Edition):

Javaherian, Clara. “Quantum transport and switching in long-range coupled quantum systems.” 2016. Doctoral Dissertation, Macquarie University. Accessed February 28, 2020. http://hdl.handle.net/1959.14/1249385.

MLA Handbook (7^th Edition):

Javaherian, Clara. “Quantum transport and switching in long-range coupled quantum systems.” 2016. Web. 28 Feb 2020.

Vancouver:

Javaherian C. Quantum transport and switching in long-range coupled quantum systems. [Internet] [Doctoral dissertation]. Macquarie University; 2016. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/1959.14/1249385.

Council of Science Editors:

Javaherian C. Quantum transport and switching in long-range coupled quantum systems. [Doctoral Dissertation]. Macquarie University; 2016. Available from: http://hdl.handle.net/1959.14/1249385

University of Cambridge

6. Adlam, Emily Christine. Relativistic quantum tasks.

Degree: PhD, 2017, University of Cambridge

URL: https://www.repository.cam.ac.uk/handle/1810/274930 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.745041

► Quantum mechanics, which describes the behaviour of matter and energy on very small scales, is one of the most successful theories in the history of… (more)

▼ Quantum mechanics, which describes the behaviour of matter and energy on very small scales, is one of the most successful theories in the history of science. Einstein's theory of special relativity, which describes the relationship between space and time, is likewise a highly successful and widely accepted theory. And yet there is a well-documented tension between the two theories, to the extent that it is still not clear that the two can ever be reconciled. This thesis is concerned with furthering the current understanding of the relationship between quantum mechanics and special relativity. In the first part of the thesis we study the behaviour of quantum information in relativistic spacetime. The field of quantum information arose from the realisation that quantum information has a number of crucial properties that distinguish it from classical information, such as the no-cloning property, quantum contextuality, and quantum discord. More recently, it has been realised that placing quantum information under relativistic constraints leads to the emergence of further unique features which are not exhibited by either non-relativistic quantum information or relativistic classical information; as part of this ongoing research programme we develop a new relativistic quantum `paradox' which puts pressure on conventional views about the spatiotemporal persistence of quantum states over time. We then study a new set of relativistic quantum protocols which involve the distribution of entangled states over spacetime, defining one task involving the distribution of the two halves of a known entangled state, and another task involving the distribution of the two halves of an unknown entangled state. The second part of the thesis deals with relativistic quantum cryptography, a field which first began attracting serious attention when it was realised that a cryptographic task known as `bit commitment,' can be implemented with perfect security under relativistic constraints. This result was highly significant, since it is provably impossible to implement bit commitment with perfect security in a purely classical or purely quantum context, and hence bit commitment is an ideal starting point for probing the power of relativistic quantum cryptography. In this thesis we propose several new relativistic quantum bit commitment protocols which have notable advantages over previously known protocols. We then move to a related task, a generalization of zero-knowledge proving which we refer to as knowledge-concealing evidencing of knowledge of a quantum state; we prove no-go theorems concerning the possibility of implementing this task with perfect security, and then set out a relativistic protocol for the task which is asymptotically secure as the dimension of the state in question becomes large. These results have interesting foundational significance above and beyond their applications in the field of cryptography, providing a new perspective on the connections between knowledge, realism and quantum states.

Subjects/Keywords: Quantum information; Quantum cryptography; Quantum foundations

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APA (6^th Edition):

Adlam, E. C. (2017). Relativistic quantum tasks. (Doctoral Dissertation). University of Cambridge. Retrieved from https://www.repository.cam.ac.uk/handle/1810/274930 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.745041

Chicago Manual of Style (16^th Edition):

Adlam, Emily Christine. “Relativistic quantum tasks.” 2017. Doctoral Dissertation, University of Cambridge. Accessed February 28, 2020. https://www.repository.cam.ac.uk/handle/1810/274930 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.745041.

MLA Handbook (7^th Edition):

Adlam, Emily Christine. “Relativistic quantum tasks.” 2017. Web. 28 Feb 2020.

Vancouver:

Adlam EC. Relativistic quantum tasks. [Internet] [Doctoral dissertation]. University of Cambridge; 2017. [cited 2020 Feb 28]. Available from: https://www.repository.cam.ac.uk/handle/1810/274930 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.745041.

Council of Science Editors:

Adlam EC. Relativistic quantum tasks. [Doctoral Dissertation]. University of Cambridge; 2017. Available from: https://www.repository.cam.ac.uk/handle/1810/274930 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.745041

University of California – Berkeley

7. Freeman, Christian Daniel. The Toric Code at Finite Temperature.

Degree: Physics, 2018, University of California – Berkeley

URL: http://www.escholarship.org/uc/item/56k7v7kq

► Alexei Kitaev's toric code is a rich model, that has birthed and stimulated the development of topological quantum computing, error correction, and field theory. It… (more)

Subjects/Keywords: Quantum physics; quantum error correction; quantum memory

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APA (6^th Edition):

Freeman, C. D. (2018). The Toric Code at Finite Temperature. (Thesis). University of California – Berkeley. Retrieved from http://www.escholarship.org/uc/item/56k7v7kq

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Freeman, Christian Daniel. “The Toric Code at Finite Temperature.” 2018. Thesis, University of California – Berkeley. Accessed February 28, 2020. http://www.escholarship.org/uc/item/56k7v7kq.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Freeman, Christian Daniel. “The Toric Code at Finite Temperature.” 2018. Web. 28 Feb 2020.

Vancouver:

Freeman CD. The Toric Code at Finite Temperature. [Internet] [Thesis]. University of California – Berkeley; 2018. [cited 2020 Feb 28]. Available from: http://www.escholarship.org/uc/item/56k7v7kq.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Freeman CD. The Toric Code at Finite Temperature. [Thesis]. University of California – Berkeley; 2018. Available from: http://www.escholarship.org/uc/item/56k7v7kq

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Wesleyan University

8. Kan, Angus. Quantum Computing: Temperature Scaling of Decoherence.

Degree: Physics, 2018, Wesleyan University

URL: https://wesscholar.wesleyan.edu/etd_mas_theses/193

► After years of effort by quantum scientists, decoherence due to thermal effects still remains a huge hindrance to the upscaling of quantum computers. This… (more)

Subjects/Keywords: Quantum; Quantum Computing; Quantum Information; Decoherence

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APA (6^th Edition):

Kan, A. (2018). Quantum Computing: Temperature Scaling of Decoherence. (Masters Thesis). Wesleyan University. Retrieved from https://wesscholar.wesleyan.edu/etd_mas_theses/193

Chicago Manual of Style (16^th Edition):

Kan, Angus. “Quantum Computing: Temperature Scaling of Decoherence.” 2018. Masters Thesis, Wesleyan University. Accessed February 28, 2020. https://wesscholar.wesleyan.edu/etd_mas_theses/193.

MLA Handbook (7^th Edition):

Kan, Angus. “Quantum Computing: Temperature Scaling of Decoherence.” 2018. Web. 28 Feb 2020.

Vancouver:

Kan A. Quantum Computing: Temperature Scaling of Decoherence. [Internet] [Masters thesis]. Wesleyan University; 2018. [cited 2020 Feb 28]. Available from: https://wesscholar.wesleyan.edu/etd_mas_theses/193.

Council of Science Editors:

Kan A. Quantum Computing: Temperature Scaling of Decoherence. [Masters Thesis]. Wesleyan University; 2018. Available from: https://wesscholar.wesleyan.edu/etd_mas_theses/193

University of Waterloo

9. Meyer-Scott, Evan. Heralding Photonic Qubits for Quantum Communication.

Degree: 2016, University of Waterloo

URL: http://hdl.handle.net/10012/10201

► Quantum communication attempts to harness the unique rules of quantum mechanics to perform communication tasks that are difficult or impossible using classical rules. To realize… (more)

▼ Quantum communication attempts to harness the unique rules of quantum mechanics to perform communication tasks that are difficult or impossible using classical rules. To realize these benefits, information must be carried on quantum systems. Photons make excellent carriers because they interact very little with the environment, move quickly, and can naturally store quantum information in their polarization. However, it is notoriously difficult to detect a single photon without destroying it. Standard detectors simply absorb the photon, losing the quantum information. This is a critical outstanding problem in quantum communication, as advanced protocols need to know exactly when a photon has arrived at a receiver after transmission through the atmosphere or an optical fibre before performing further quantum-information-processing tasks. Certifying a photon’s presence is of particular interest in tests of Bell’s inequalities, which have only recently been performed without loopholes arising from photon loss, and in device-independent quantum cryptography, which relies on such Bell tests for security. In this thesis, I first present work on directly reducing losses in a successful loophole-free Bell test. This is an extremely difficult task that cannot be extended for long-distance communication. Therefore I then focus on ways to circumvent loss by detecting photons without destroying them while preserving their quantum information. First I analyze theoretically a way to herald photons using only linear-optical elements (beam splitters and phase shifters) and extra ancilla photons. Similar but older methods have been demonstrated experimentally by other groups, and my improvements will help future advanced quantum communication protocols. The main experiment in this thesis certifies the presence of a photon in a rather simple way: split the photon into two using a nonlinear optical crystal, then detect one of the pair to herald the other. I show in this first proof-of-principle experiment that photonic qubit precertification indeed preserves qubit states, with up to (92.3 ± 0.6)% fidelity and rates of 1100 events per hour. With reductions in detector dark counts, precertification could outperform direct transmission, even with extremely lossy fibre links. Finally, I present two sources of photons based on nonlinearities in optical fibres. One of the limitations of the photon splitting scheme for heralding is the low success probability due to the very low likelihood of splitting a photon in two. In these fibre photon sources I investigate increasing the splitting likelihood in four-wave mixing through advanced materials and fibre designs. I use polarization-maintaining fibres to generate entangled photon pairs as a prerequisite to precertification, with (92.2 ± 0.2)% fidelity to a maximally-entangled state. Then I show that one type of highly nonlinear chalcogenide glass, never before used for photon pair generation, could outperform standard nonlinear crystals by two orders of magnitude, with calculated…

Subjects/Keywords: quantum optics; quantum information; quantum communication; photonics

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APA (6^th Edition):

Meyer-Scott, E. (2016). Heralding Photonic Qubits for Quantum Communication. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/10201

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Meyer-Scott, Evan. “Heralding Photonic Qubits for Quantum Communication.” 2016. Thesis, University of Waterloo. Accessed February 28, 2020. http://hdl.handle.net/10012/10201.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Meyer-Scott, Evan. “Heralding Photonic Qubits for Quantum Communication.” 2016. Web. 28 Feb 2020.

Vancouver:

Meyer-Scott E. Heralding Photonic Qubits for Quantum Communication. [Internet] [Thesis]. University of Waterloo; 2016. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/10012/10201.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Meyer-Scott E. Heralding Photonic Qubits for Quantum Communication. [Thesis]. University of Waterloo; 2016. Available from: http://hdl.handle.net/10012/10201

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Waterloo

10. Layden, David. Indirect Quantum Control: An Implementation-Independent Scheme.

Degree: 2016, University of Waterloo

URL: http://hdl.handle.net/10012/10645

► The ability to control quantum systems rapidly as compared to their coherence times is a central requirement for most proposed quantum technologies, such as quantum… (more)

Subjects/Keywords: Quantum physics; Quantum computing; Quantum control

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APA (6^th Edition):

Layden, D. (2016). Indirect Quantum Control: An Implementation-Independent Scheme. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/10645

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Layden, David. “Indirect Quantum Control: An Implementation-Independent Scheme.” 2016. Thesis, University of Waterloo. Accessed February 28, 2020. http://hdl.handle.net/10012/10645.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Layden, David. “Indirect Quantum Control: An Implementation-Independent Scheme.” 2016. Web. 28 Feb 2020.

Vancouver:

Layden D. Indirect Quantum Control: An Implementation-Independent Scheme. [Internet] [Thesis]. University of Waterloo; 2016. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/10012/10645.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Layden D. Indirect Quantum Control: An Implementation-Independent Scheme. [Thesis]. University of Waterloo; 2016. Available from: http://hdl.handle.net/10012/10645

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Waterloo

11. Kothari, Robin. Efficient algorithms in quantum query complexity.

Degree: 2014, University of Waterloo

URL: http://hdl.handle.net/10012/8625

► In this thesis we provide new upper and lower bounds on the quantum query complexity of a diverse set of problems. Specifically, we study quantum… (more)

▼ In this thesis we provide new upper and lower bounds on the quantum query complexity of a diverse set of problems. Specifically, we study quantum algorithms for Hamiltonian simulation, matrix multiplication, oracle identification, and graph-property recognition. For the Hamiltonian simulation problem, we provide a quantum algorithm with query complexity sublogarithmic in the inverse error, an exponential improvement over previous methods. Our algorithm is based on a new quantum algorithm for implementing unitary matrices that can be written as linear combinations of efficiently implementable unitary gates. This algorithm uses a new form of ``oblivious amplitude amplification'' that can be applied even though the reflection about the input state is unavailable. In the oracle identification problem, we are given oracle access to an unknown N-bit string x promised to belong to a known set of size M, and our task is to identify x. We present the first quantum algorithm for the problem that is optimal in its dependence on N and M. Our algorithm is based on ideas from classical learning theory and a new composition theorem for solutions of the filtered gamma_2-norm semidefinite program. We then study the quantum query complexity of matrix multiplication and related problems over rings, semirings, and the Boolean semiring in particular. Our main result is an output-sensitive algorithm for Boolean matrix multiplication that multiplies two n x n Boolean matrices with query complexity O(n sqrt{l}), where l is the sparsity of the output matrix. The algorithm is based on a reduction to the graph collision problem and a new algorithm for graph collision. Finally, we study the quantum query complexity of minor-closed graph properties and show that most minor-closed properties – those that cannot be characterized by a finite set of forbidden subgraphs – have quantum query complexity Theta(n^3/2) and those that do have such a characterization can be solved strictly faster, with o(n^3/2) queries. Our lower bound is based on a detailed analysis of the structure of minor-closed properties with respect to forbidden topological minors and forbidden subgraphs. Our algorithms are a novel application of the quantum walk search framework and give improved upper bounds for several subgraph-finding problems.

Subjects/Keywords: Quantum computing; Quantum algorithms; Quantum query complexity

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APA (6^th Edition):

Kothari, R. (2014). Efficient algorithms in quantum query complexity. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/8625

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kothari, Robin. “Efficient algorithms in quantum query complexity.” 2014. Thesis, University of Waterloo. Accessed February 28, 2020. http://hdl.handle.net/10012/8625.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kothari, Robin. “Efficient algorithms in quantum query complexity.” 2014. Web. 28 Feb 2020.

Vancouver:

Kothari R. Efficient algorithms in quantum query complexity. [Internet] [Thesis]. University of Waterloo; 2014. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/10012/8625.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kothari R. Efficient algorithms in quantum query complexity. [Thesis]. University of Waterloo; 2014. Available from: http://hdl.handle.net/10012/8625

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Waterloo

12. Daley, Patrick. Causal Discovery of Photonic Bell Experiments.

Degree: 2020, University of Waterloo

URL: http://hdl.handle.net/10012/15446

► A causal understanding of a physical theory is vital. They provide profound insights into the implications of the theory and contain the information required to… (more)

Subjects/Keywords: quantum foundations; causal inference; quantum optics; quantum

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APA (6^th Edition):

Daley, P. (2020). Causal Discovery of Photonic Bell Experiments. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/15446

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Daley, Patrick. “Causal Discovery of Photonic Bell Experiments.” 2020. Thesis, University of Waterloo. Accessed February 28, 2020. http://hdl.handle.net/10012/15446.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Daley, Patrick. “Causal Discovery of Photonic Bell Experiments.” 2020. Web. 28 Feb 2020.

Vancouver:

Daley P. Causal Discovery of Photonic Bell Experiments. [Internet] [Thesis]. University of Waterloo; 2020. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/10012/15446.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Daley P. Causal Discovery of Photonic Bell Experiments. [Thesis]. University of Waterloo; 2020. Available from: http://hdl.handle.net/10012/15446

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

13. Schmitz, Albert Thomas. Quantum Walks: Theory, Application, And Implementation.

Degree: MS, Physics & Astrophysics, 2016, University of North Dakota

URL: https://commons.und.edu/theses/1959

► The quantum walk is a method for conceptualizing and designing quantum computing algorithms and it comes in two forms: the continuous-time and discrete-time quantum… (more)

Subjects/Keywords: Quantum Algorithm; Quantum Computing; Quantum Walks

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APA (6^th Edition):

Schmitz, A. T. (2016). Quantum Walks: Theory, Application, And Implementation. (Masters Thesis). University of North Dakota. Retrieved from https://commons.und.edu/theses/1959

Chicago Manual of Style (16^th Edition):

Schmitz, Albert Thomas. “Quantum Walks: Theory, Application, And Implementation.” 2016. Masters Thesis, University of North Dakota. Accessed February 28, 2020. https://commons.und.edu/theses/1959.

MLA Handbook (7^th Edition):

Schmitz, Albert Thomas. “Quantum Walks: Theory, Application, And Implementation.” 2016. Web. 28 Feb 2020.

Vancouver:

Schmitz AT. Quantum Walks: Theory, Application, And Implementation. [Internet] [Masters thesis]. University of North Dakota; 2016. [cited 2020 Feb 28]. Available from: https://commons.und.edu/theses/1959.

Council of Science Editors:

Schmitz AT. Quantum Walks: Theory, Application, And Implementation. [Masters Thesis]. University of North Dakota; 2016. Available from: https://commons.und.edu/theses/1959

University of New South Wales

14. Wheatley, Trevor. To the standard quantum limit and beyond: Experimental quantum parameter estimation using adaptive quantum smoothing.

Degree: Engineering & Information Technology, 2016, University of New South Wales

URL: http://handle.unsw.edu.au/1959.4/55888 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:39598/SOURCE02?view=true

► Quantum parameter estimation (QPE) is the ability to precisely estimate a classical parameter in a quantum system. QPE is important to many key quantum disciplines… (more)

▼ Quantum parameter estimation (QPE) is the ability to precisely estimate a classical parameter in a quantum system. QPE is important to many key quantum disciplines such as quantum control, gravitational wave detection and quantum key distribution. The discipline of QPE is driven by the pursuit of precision limited only by quantum mechanics, with benchmarks like the standard quantum limit (SQL) and the illusive Heisenberg limit. Many techniques promising greater precision have been proposed and demonstrated. Here we expand the QPE body of knowledge by demonstrating QPE techniques for estimating optical phase and mirror position in quantum optical systems. We demonstrate new and existing techniques, comparing the results with existing limits of precision. Our techniques lower traditional precision levels with further improvement obtained when quantum enhancement is employed.In this thesis we present results from the first demonstrations of adaptive and dual homodyne detection using time-asymmetric quantum filtering to estimate a continuously varying optical phase. In this work we approach the SQL using dual homodyne detection and go beyond the SQL by 1.2 +/- 0.08 times with an adaptive homodyne measurement.We additionally present results from the first experimental demonstration of optical phase estimation using time-symmetric quantum smoothing. Here we go beyond the SQL with both dual homodyne and adaptive homodyne by 2.24 +/- 0.14 times for the latter. This is extended to an experimental demonstration of quantum enhanced optical phase estimation using quantum smoothing. We define a new limit, the coherent state limit (CSL), our best precision achievable with a coherent state. With quantum enhancement we beat the CSL by approximately 15 +/- 4% and introduce a paradox where too much squeezing exists.We present theory and simulation validated by experiment for resonance enhanced quantum smoothing. When estimating the position of a mechanically resonant cavity mirror, this technique shows a precision enhancement of greater than two compared with optimal filtering. Previously smoothing enhancement has not exceeded two.Finally, theoretical and simulation results are provided for quantum enhanced mirror position estimation using resonant quantum smoothing. Our results indicate precision improvement of approximately 20 +/- 4% with quantum enhancement. Advisors/Committee Members: Petersen, Ian, Information Technology & Electrical Engineering, UNSW Canberra, UNSW, Huntington, Elanor, Research School of Engineering, College of Engineering and Computer Science, Australian National University.

Subjects/Keywords: Quantum control; Quantum parameter estimation; Quantum optics

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APA (6^th Edition):

Wheatley, T. (2016). To the standard quantum limit and beyond: Experimental quantum parameter estimation using adaptive quantum smoothing. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/55888 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:39598/SOURCE02?view=true

Chicago Manual of Style (16^th Edition):

Wheatley, Trevor. “To the standard quantum limit and beyond: Experimental quantum parameter estimation using adaptive quantum smoothing.” 2016. Doctoral Dissertation, University of New South Wales. Accessed February 28, 2020. http://handle.unsw.edu.au/1959.4/55888 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:39598/SOURCE02?view=true.

MLA Handbook (7^th Edition):

Wheatley, Trevor. “To the standard quantum limit and beyond: Experimental quantum parameter estimation using adaptive quantum smoothing.” 2016. Web. 28 Feb 2020.

Vancouver:

Wheatley T. To the standard quantum limit and beyond: Experimental quantum parameter estimation using adaptive quantum smoothing. [Internet] [Doctoral dissertation]. University of New South Wales; 2016. [cited 2020 Feb 28]. Available from: http://handle.unsw.edu.au/1959.4/55888 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:39598/SOURCE02?view=true.

Council of Science Editors:

Wheatley T. To the standard quantum limit and beyond: Experimental quantum parameter estimation using adaptive quantum smoothing. [Doctoral Dissertation]. University of New South Wales; 2016. Available from: http://handle.unsw.edu.au/1959.4/55888 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:39598/SOURCE02?view=true

Princeton University

15. Liu, Yanbing. Reservoir engineering in circuit quantum electrodynamics .

Degree: PhD, 2016, Princeton University

URL: http://arks.princeton.edu/ark:/88435/dsp01mw22v794j

► Superconducting circuits have become an ideal platform to implement prototypi- cal quantum computing ideas and to study nonequilibrium quantum dynamics. This thesis covers research topics… (more)

Subjects/Keywords: quantum computing; quantum electrodynamics; quantum optics

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APA (6^th Edition):

Liu, Y. (2016). Reservoir engineering in circuit quantum electrodynamics . (Doctoral Dissertation). Princeton University. Retrieved from http://arks.princeton.edu/ark:/88435/dsp01mw22v794j

Chicago Manual of Style (16^th Edition):

Liu, Yanbing. “Reservoir engineering in circuit quantum electrodynamics .” 2016. Doctoral Dissertation, Princeton University. Accessed February 28, 2020. http://arks.princeton.edu/ark:/88435/dsp01mw22v794j.

MLA Handbook (7^th Edition):

Liu, Yanbing. “Reservoir engineering in circuit quantum electrodynamics .” 2016. Web. 28 Feb 2020.

Vancouver:

Liu Y. Reservoir engineering in circuit quantum electrodynamics . [Internet] [Doctoral dissertation]. Princeton University; 2016. [cited 2020 Feb 28]. Available from: http://arks.princeton.edu/ark:/88435/dsp01mw22v794j.

Council of Science Editors:

Liu Y. Reservoir engineering in circuit quantum electrodynamics . [Doctoral Dissertation]. Princeton University; 2016. Available from: http://arks.princeton.edu/ark:/88435/dsp01mw22v794j

Nelson Mandela Metropolitan University

16. Tile, Ngcali. AP-MOVPE growth and characterisation of GaSb/GaAs quantum dots.

Degree: 2018, Nelson Mandela Metropolitan University

URL: http://hdl.handle.net/10948/36716

► GaSb/GaAs quantum dots (QD) were grown by atmospheric pressure (AP) metal-organic vapour phase epitaxy (MOVPE) using triethylgallium (TEGa), tertiarybutylarsine (tBAs) and trimethylantimony (TMSb) as gallium… (more)

▼ GaSb/GaAs quantum dots (QD) were grown by atmospheric pressure (AP) metal-organic vapour phase epitaxy (MOVPE) using triethylgallium (TEGa), tertiarybutylarsine (tBAs) and trimethylantimony (TMSb) as gallium (Ga), arsenic (As) and (Sb) sources, respectively. The effect of AP-MOVPE growth parameters on the formation of GaSb QD structures on GaAs was studied. The formation of small, coherent GaSb dots on GaAs improved with decreasing V/III ratios, which were controlled through changing either the TMSb/TEGa ratio at a constant growth temperature or changing the growth temperature at a constant TMSb/TEGa ratio. The maximum effective V/III ratio for dot formation was 0.175. The dot density was more sensitive to growth time than to source mole fraction in the reactor, since time determines the amount of deposited material. The dot density increased with increasing growth time, while the shape and size of the dots were more sensitive to the source vapour mole fraction, which controls the growth rate. Lower mole fractions resulted in smaller sized dots with a more uniform distribution compared to higher mole fractions. Dome-shaped dots with densities as high as 4×1010 cm-2, average base length of 35 nm and average height of 5 nm were achieved. Capping of GaSb QDs at high temperatures caused flattening and the formation of a thin, inhomogeneous GaSb layer inside GaAs. No obvious QD photoluminescence (PL) peak was detected for these samples. A two stage process for capping the dots (involving growth of a low temperature GaAs cap, followed by a high temperature cap) led to the retention of the dot-like features in/on a wetting layer (WL) of GaSb and distinct PL peaks for both the QDs and WL. An increase in excitation power during PL measurements for this particular sample caused the QD and WL peaks to shift to higher energies. This is attributed to electrostatic band bending, leading to triangular potential wells, typical for type II band alignment between GaAs and strained GaSb. Variable temperature PL measurements showed the decrease in the intensity of the WL peak to be faster than that of the QD peak as the measurement temperature increased. A detailed high resolution transmission electron microscopy analysis was performed to study the morphology and chemical interaction between GaAs and GaSb regions for capped GaSb/GaAs QDs. The capped dots had dimensions similar to those of uncapped dots and had a higher concentration of Sb at their center, with the periphery being intermixed with GaAs. Measurement of lattice strain performed inside these dots revealed the strain to be distributed inhomogenously throughout the dot area. The effect of GaAs host matrix on excitonic behaviour in AP-MOVPE grown GaSb/GaAs quantum dots was investigated. Room temperature (RT) PL emission was achieved from a single layer of quantum dots by controlling the GaAs host matrix growth temperature. These samples were prepared using a GaSb dot growth temperature of 530 °C, followed by growth of a thin GaAs ‘cold’ cap, before depositing the final part of…

Subjects/Keywords: Quantum theory; Quantum electronics; Quantum dots; Semiconductors

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Tile, N. (2018). AP-MOVPE growth and characterisation of GaSb/GaAs quantum dots. (Thesis). Nelson Mandela Metropolitan University. Retrieved from http://hdl.handle.net/10948/36716

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Tile, Ngcali. “AP-MOVPE growth and characterisation of GaSb/GaAs quantum dots.” 2018. Thesis, Nelson Mandela Metropolitan University. Accessed February 28, 2020. http://hdl.handle.net/10948/36716.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Tile, Ngcali. “AP-MOVPE growth and characterisation of GaSb/GaAs quantum dots.” 2018. Web. 28 Feb 2020.

Vancouver:

Tile N. AP-MOVPE growth and characterisation of GaSb/GaAs quantum dots. [Internet] [Thesis]. Nelson Mandela Metropolitan University; 2018. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/10948/36716.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Tile N. AP-MOVPE growth and characterisation of GaSb/GaAs quantum dots. [Thesis]. Nelson Mandela Metropolitan University; 2018. Available from: http://hdl.handle.net/10948/36716

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Waterloo

17. Marwah, Ashutosh Satyajit. Optical Quantum Communication & Cryptography with Temporarily Trusted Parties.

Degree: 2019, University of Waterloo

URL: http://hdl.handle.net/10012/15087

► The work in this thesis can be divided into three parts. The first two parts deal with optical quantum communication protocols and the third part… (more)

▼ The work in this thesis can be divided into three parts. The first two parts deal with optical quantum communication protocols and the third part deals with quantum cryptography. The first part of the thesis is a step towards reformulating quantum protocols in terms of coherent states. Quantum communication protocols are typically formulated in terms of abstract qudit states and operations. This leaves the question of an experimental realization open. Direct translation of these protocols, say into single photons with some d-dimensional degree of freedom, are typically challenging to realize. Multi-mode coherent states, on the other hand, can be easily generated experimentally. Reformulation of protocols in terms of these states has been a successful strategy for implementation of quantum protocols. Quantum key distribution and the quantum fingerprinting protocol have both followed this route. In Chapter 3, we characterize the Gram matrices of multi-mode coherent states in an attempt to understand the class of communication protocols, which can be implemented using these states. We also derive the closure of the Gram matrices, which can be implemented in this way, so that we also characterize those matrices, which can be approximated arbitrarily well using multi-mode coherent states. In the second part of the thesis, Chapter 4, we describe our collaboration with an experimental group to implement the quantum fingerprinting protocol and examine the tradeoffs between the resources required to implement such protocols. It is seen that it is difficult to implement the quantum fingerprinting protocol experimentally for large input sizes. This leads us to study the tradeoff between the two resources expended during optically implemented simultaneous message passing communication protocols: the duration of the protocol and the energy required to run it. We derive general bounds on the growth of these quantities which are valid for all optical protocols. We also develop tighter bounds for the growth of these resources for protocols implementing quantum fingerprinting with coherent states. Finally in Chapter 5, we venture into quantum cryptography. We introduce a new setting for two-party cryptography with temporarily trusted third parties. In this setting, in addition to Alice and Bob, there are third parties, which Alice and Bob both trust to be honest during the course of the protocol. However, once the protocol concludes, there is no guarantee over the behaviour of these third parties. It is possible that they collaborate and act adversarially against the honest parties. We implement a variant of bit commitment in this setting, which we call erasable bit commitment. In this primitive, Alice has the choice of either opening or erasing her commitment after the commit phase. The ability to ask for an erasure allows Alice to ask the trusted nodes to erase her commitment in case the trust period is about to expire. However, this ability also makes erasable bit commitment weaker than the standard version of bit…

Subjects/Keywords: quantum communication; quantum optics; quantum cryptography

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APA (6^th Edition):

Marwah, A. S. (2019). Optical Quantum Communication & Cryptography with Temporarily Trusted Parties. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/15087

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Marwah, Ashutosh Satyajit. “Optical Quantum Communication & Cryptography with Temporarily Trusted Parties.” 2019. Thesis, University of Waterloo. Accessed February 28, 2020. http://hdl.handle.net/10012/15087.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Marwah, Ashutosh Satyajit. “Optical Quantum Communication & Cryptography with Temporarily Trusted Parties.” 2019. Web. 28 Feb 2020.

Vancouver:

Marwah AS. Optical Quantum Communication & Cryptography with Temporarily Trusted Parties. [Internet] [Thesis]. University of Waterloo; 2019. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/10012/15087.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Marwah AS. Optical Quantum Communication & Cryptography with Temporarily Trusted Parties. [Thesis]. University of Waterloo; 2019. Available from: http://hdl.handle.net/10012/15087

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Technology, Sydney

18. Su, Zhaofeng. Quantification and distribution of genuinely nonlocal resources.

Degree: 2018, University of Technology, Sydney

URL: http://hdl.handle.net/10453/129356

► Quantum mechanics is nonlocal, which makes it different from classical mechanics. Quantum information and quantum computation is a promising frontier science which is based on… (more)

▼ Quantum mechanics is nonlocal, which makes it different from classical mechanics. Quantum information and quantum computation is a promising frontier science which is based on quantum mechanics. The nonlocality of quantum mechanics is the fundamental reason that many quantum information processing tasks have significant advantages over their classical counterparts. In this dissertation, we study three aspects of quantum nonlocality, which include the quantitative relationship between entanglement and nonlocality, the quantification of genuine tripartite nonlocality and the distribution of nonlocal quantum resources. To be specific, • We investigate the quantitative relationship between entanglement and nonlocality of bipartite quantum systems. We start by exploiting the condition that the nonlocality of two different two-qubit states can be optimally examined by a same nonlocality test setting. Via numerical simulation, we find that the nonlocality of a generic two-qubit state is upper bounded by a function of the corresponding entanglement. Further, we give an analytical proof for the upper bound and find the class of two-qubit states that can reach the upper bound. • We analyze the quantification of genuine tripartite nonlocality of a generic three-qubit state. We find a method to solve the problem for a special class of three-qubit states which include not only pure states but also mixed states. Applying the method, we drive analytical results for the genuine tripartite nonlocality of generalized GHZ states, generalized Werner states and two class of mixed states with special correlation matrices. • We investigate the distribution of nonlocal quantum resources. To distribute bipartite nonlocal quantum resources, we design an efficient quantum repeater scheme, which not only achieves the optimal transmission rate but also consumes less resources of local operations and classical communication, for the case of general pure states of two-qubit system. We also analyze the case of bipartite pure states of arbitrary dimensional quantum system and get an upper bound on the probability of a successful projection operation to produce a maximally nonlocal state. To distribute tripartite nonlocal resources, we propose a simple scenario to generate tripartite nonlocal resources from bipartite nonlocal resources. As examples, we examine the cases that two-qubit Werner states and general two-qubit pure states are prepared as resources, respectively. We get the upper bounds on the genuine tripartite nonlocality that can be generated in the scenario. We also provide the optimal measurement settings to achieve the upper bounds.

Subjects/Keywords: Quantum mechanics; Quantum nonlocality; Bipartite quantum systems

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APA (6^th Edition):

Su, Z. (2018). Quantification and distribution of genuinely nonlocal resources. (Thesis). University of Technology, Sydney. Retrieved from http://hdl.handle.net/10453/129356

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Su, Zhaofeng. “Quantification and distribution of genuinely nonlocal resources.” 2018. Thesis, University of Technology, Sydney. Accessed February 28, 2020. http://hdl.handle.net/10453/129356.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Su, Zhaofeng. “Quantification and distribution of genuinely nonlocal resources.” 2018. Web. 28 Feb 2020.

Vancouver:

Su Z. Quantification and distribution of genuinely nonlocal resources. [Internet] [Thesis]. University of Technology, Sydney; 2018. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/10453/129356.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Su Z. Quantification and distribution of genuinely nonlocal resources. [Thesis]. University of Technology, Sydney; 2018. Available from: http://hdl.handle.net/10453/129356

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

19. O'Malley, Peter James Joyce. Superconducting Qubits: Dephasing and Quantum Chemistry.

Degree: 2016, University of California – eScholarship, University of California

URL: http://www.escholarship.org/uc/item/21x6x9tk

► One of the most exciting potential applications of a quantum computer is the abilityto efficiently simulate quantum systems, a task that is out of the… (more)

Subjects/Keywords: Quantum physics; Physics; Chemistry; Quantum Algorithms; Quantum Chemistry; Quantum Computation; Quantum Information; Quantum Noise

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APA (6^th Edition):

O'Malley, P. J. J. (2016). Superconducting Qubits: Dephasing and Quantum Chemistry. (Thesis). University of California – eScholarship, University of California. Retrieved from http://www.escholarship.org/uc/item/21x6x9tk

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

O'Malley, Peter James Joyce. “Superconducting Qubits: Dephasing and Quantum Chemistry.” 2016. Thesis, University of California – eScholarship, University of California. Accessed February 28, 2020. http://www.escholarship.org/uc/item/21x6x9tk.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

O'Malley, Peter James Joyce. “Superconducting Qubits: Dephasing and Quantum Chemistry.” 2016. Web. 28 Feb 2020.

Vancouver:

O'Malley PJJ. Superconducting Qubits: Dephasing and Quantum Chemistry. [Internet] [Thesis]. University of California – eScholarship, University of California; 2016. [cited 2020 Feb 28]. Available from: http://www.escholarship.org/uc/item/21x6x9tk.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

O'Malley PJJ. Superconducting Qubits: Dephasing and Quantum Chemistry. [Thesis]. University of California – eScholarship, University of California; 2016. Available from: http://www.escholarship.org/uc/item/21x6x9tk

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

20. Potoček Václav. Quantum Walks .

Degree: 2013, Czech University of Technology

URL: http://hdl.handle.net/10467/14024

Quantum Walks:New theoretical and experimental results; Quantum Walks:New theoretical and experimental results Advisors/Committee Members: Jex Igor (advisor).

Subjects/Keywords: Quantum Walks; Quantum algorithms

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APA (6^th Edition):

Václav, P. (2013). Quantum Walks . (Thesis). Czech University of Technology. Retrieved from http://hdl.handle.net/10467/14024

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Václav, Potoček. “Quantum Walks .” 2013. Thesis, Czech University of Technology. Accessed February 28, 2020. http://hdl.handle.net/10467/14024.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Václav, Potoček. “Quantum Walks .” 2013. Web. 28 Feb 2020.

Vancouver:

Václav P. Quantum Walks . [Internet] [Thesis]. Czech University of Technology; 2013. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/10467/14024.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Václav P. Quantum Walks . [Thesis]. Czech University of Technology; 2013. Available from: http://hdl.handle.net/10467/14024

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of KwaZulu-Natal

21. Mpofu, Kelvin Tafadzwa. Quantum analogues of classical optimization algorithms.

Degree: 2017, University of KwaZulu-Natal

URL: http://hdl.handle.net/10413/15712

► This thesis explores the quantum analogues of algorithms used in mathematical optimization. The thesis focuses primarily on the iterative gradient search algorithm (algorithm for finding… (more)

Subjects/Keywords: Quantum optimization.; Quantum algorithms.

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APA (6^th Edition):

Mpofu, K. T. (2017). Quantum analogues of classical optimization algorithms. (Thesis). University of KwaZulu-Natal. Retrieved from http://hdl.handle.net/10413/15712

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Mpofu, Kelvin Tafadzwa. “Quantum analogues of classical optimization algorithms.” 2017. Thesis, University of KwaZulu-Natal. Accessed February 28, 2020. http://hdl.handle.net/10413/15712.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Mpofu, Kelvin Tafadzwa. “Quantum analogues of classical optimization algorithms.” 2017. Web. 28 Feb 2020.

Vancouver:

Mpofu KT. Quantum analogues of classical optimization algorithms. [Internet] [Thesis]. University of KwaZulu-Natal; 2017. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/10413/15712.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Mpofu KT. Quantum analogues of classical optimization algorithms. [Thesis]. University of KwaZulu-Natal; 2017. Available from: http://hdl.handle.net/10413/15712

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of New Mexico

22. Riofrío, Almeida Carlos. Continuous measurement quantum state tomography of atomic ensembles.

Degree: Physics & Astronomy, 2012, University of New Mexico

URL: http://hdl.handle.net/1928/17499

► Quantum state tomography is a fundamental tool in quantum information processing tasks. It allows us to estimate the state of a quantum system by measuring… (more)

▼ Quantum state tomography is a fundamental tool in quantum information processing tasks. It allows us to estimate the state of a quantum system by measuring different observables on many identically prepared copies of the system. Usually, one makes projective measurements of an informationally complete set of observables and repeats them enough times so that good estimates of their expectation values are obtained. This is, in general, a very time-consuming task that requires a large number of measurements. There are, however, systems in which the data acquisition can be done more efficiently. In fact, an ensemble of quantum systems can be prepared and manipulated by external fields while being continuously probed collectively, producing enough information to estimate its state. This provides a basis for continuous measurement quantum tomography, and is the main topic of this dissertation. This method, based on weak continuous measurement, has the advantage of being fast, accurate, and almost nonperturbative. In this work, we present a extensive discussion and a generalization of the protocol proposed in [1], which was experimentally achieved in [2] using cold cesium atoms. In this protocol, an ensemble of identically prepared systems is collectively probed and controlled in a time-dependent manner so as to create an informationally complete continuous measurement record. The measurement history is then inverted to determine the state at the initial time. To achieve this, we use two different estimation methods: the widely used maximum likelihood and the novel compressed sensing algorithms. The general formalism is applied to the case of reconstruction of the quantum state encoded in the magnetic sub-levels of a large-spin alkali atom, 133Cs. We extend the applicability of the protocol in [1] to the more ambitious case of reconstruction of states in the full 16-dimensional electronic-ground subspace (F = 3 \u2295 F = 4), controlled by microwaves and radio-frequency magnetic fields. We give detailed derivations of all physical interactions, approximations, numerical methods, and fitting procedures, tailored to the realistic experimental setting. In addition, we numerically study the reconstruction algorithms and determine their applicability and appropriate use. Moreover, in collaboration with the lab of Prof. P. Jessen at the University of Arizona, we present an experimental demonstration of continuous measurement quantum tomography in an ensemble of cold cesium atoms with full control of its 16-dimensional Hilbert space. In this case, we show the exquisite level of control achieved in the lab and the excellent agreement between the theory discussed in this dissertation and the experimental results. This allows us to achieve fidelities > 95% for low complexity quantum states, and > 92% for arbitrary random states, which is a formidable accomplishment for a space of this size. To conclude this work, we study quantum tomography in an abstract system driven by random dynamics and show the conditions for… Advisors/Committee Members: Deutsch, Ivan, Deutsch, Ivan, Caves, Carlton, Jessen, Poul, Jayaweera, Sudharman.

Subjects/Keywords: Quantum computers; Quantum entanglement.

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APA (6^th Edition):

Riofrío, A. C. (2012). Continuous measurement quantum state tomography of atomic ensembles. (Doctoral Dissertation). University of New Mexico. Retrieved from http://hdl.handle.net/1928/17499

Chicago Manual of Style (16^th Edition):

Riofrío, Almeida Carlos. “Continuous measurement quantum state tomography of atomic ensembles.” 2012. Doctoral Dissertation, University of New Mexico. Accessed February 28, 2020. http://hdl.handle.net/1928/17499.

MLA Handbook (7^th Edition):

Riofrío, Almeida Carlos. “Continuous measurement quantum state tomography of atomic ensembles.” 2012. Web. 28 Feb 2020.

Vancouver:

Riofrío AC. Continuous measurement quantum state tomography of atomic ensembles. [Internet] [Doctoral dissertation]. University of New Mexico; 2012. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/1928/17499.

Council of Science Editors:

Riofrío AC. Continuous measurement quantum state tomography of atomic ensembles. [Doctoral Dissertation]. University of New Mexico; 2012. Available from: http://hdl.handle.net/1928/17499

University of Illinois – Urbana-Champaign

23. Christensen, Bradley G. Advanced tests of nonlocality with entangled photons.

Degree: PhD, Physics, 2016, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/90538

► In 1935, Einstein, Podolsky, and Rosen questioned whether quantum mechanics can be complete, as it seemingly does not adhere to a natural view of reality:… (more)

▼ In 1935, Einstein, Podolsky, and Rosen questioned whether quantum mechanics can be complete, as it seemingly does not adhere to a natural view of reality: local realism, which is the notion that an event can only be influenced by events in the past lightcone, and can only influence events in the future lightcone. This question sparked a philosophical debate that lasted for three decades, until John Bell demonstrated that not only are quantum mechanics and local realism philosophically incompatible, but they predict different statistical results for an appropriate set of measurements on entangled particles, which changed the debate to a scientific discussion. Since then, Bell inequality violations have occurred in a plethora of systems, hinting that local realism is indeed wrong. However, every experiment had imperfections that complicated the interpretation – the experiments had so-called "loopholes" which allowed local realism to persist. In this manuscript, we present our work in using optimized sources of entangled photons to perform the long-sought loophole-free Bell test. This landmark experiment invalidates local realism to the best that science will allow. Beyond answering questions on reality, these Bell tests have a important application in generating provably-secure private random numbers, which then can be used as a seed for cryptographic applications. Not only do we demonstrate that nonlocality must exist, but we begin an experimental exploration in an attempt to understand and quantify this nonlocality. We do so by considering all theories that obey no-signaling (or relativistic causality). In our experiments, we observe the counter-intuitive feature of measuring more nonlocality with less entangled states. We also place a bound on the predictive power of any theory that obeys relativistic causality. And finally, we are able to measure quantum correlations only attainable through complex qubits. This work merely begins to probe the quantum boundary, beginning a journey that may someday find evidence of a beyond-quantum theory. Advisors/Committee Members: Kwiat, Paul G (advisor), Eckstein, James (Committee Chair), Leggett, Anthony (committee member), Mason, Nadya (committee member).

Subjects/Keywords: Quantum nonlocality; Quantum information

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APA (6^th Edition):

Christensen, B. G. (2016). Advanced tests of nonlocality with entangled photons. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/90538

Chicago Manual of Style (16^th Edition):

Christensen, Bradley G. “Advanced tests of nonlocality with entangled photons.” 2016. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed February 28, 2020. http://hdl.handle.net/2142/90538.

MLA Handbook (7^th Edition):

Christensen, Bradley G. “Advanced tests of nonlocality with entangled photons.” 2016. Web. 28 Feb 2020.

Vancouver:

Christensen BG. Advanced tests of nonlocality with entangled photons. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2016. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/2142/90538.

Council of Science Editors:

Christensen BG. Advanced tests of nonlocality with entangled photons. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2016. Available from: http://hdl.handle.net/2142/90538

University of Rochester

24. Nihira, Hideomi (1979 - ). Generation and applications of multi-partite multi-level quantum entanglement.

Degree: PhD, 2010, University of Rochester

URL: http://hdl.handle.net/1802/11377

► In this thesis we present a new multi-level multi-partite quantum protocol which utilizes residual entanglement in order to generate a secure key for cryptographic communication.… (more)

Subjects/Keywords: Quantum entropy; Quantum correlation

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APA (6^th Edition):

Nihira, H. (. -. ). (2010). Generation and applications of multi-partite multi-level quantum entanglement. (Doctoral Dissertation). University of Rochester. Retrieved from http://hdl.handle.net/1802/11377

Chicago Manual of Style (16^th Edition):

Nihira, Hideomi (1979 - ). “Generation and applications of multi-partite multi-level quantum entanglement.” 2010. Doctoral Dissertation, University of Rochester. Accessed February 28, 2020. http://hdl.handle.net/1802/11377.

MLA Handbook (7^th Edition):

Nihira, Hideomi (1979 - ). “Generation and applications of multi-partite multi-level quantum entanglement.” 2010. Web. 28 Feb 2020.

Vancouver:

Nihira H(-). Generation and applications of multi-partite multi-level quantum entanglement. [Internet] [Doctoral dissertation]. University of Rochester; 2010. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/1802/11377.

Council of Science Editors:

Nihira H(-). Generation and applications of multi-partite multi-level quantum entanglement. [Doctoral Dissertation]. University of Rochester; 2010. Available from: http://hdl.handle.net/1802/11377

University of Auckland

25. de Oliveira, Felipe Dimer. Study of the Dicke model: from phase space approach to quantum trajectories.

Degree: 2008, University of Auckland

URL: http://hdl.handle.net/2292/3106

► In this thesis we study the Dicke model outside the rotating wave approximation (RWA), by employing phase space techniques and the quantum trajectory theory. We… (more)

Subjects/Keywords: Superradiance; quantum noise; quantum trajectories

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APA (6^th Edition):

de Oliveira, F. D. (2008). Study of the Dicke model: from phase space approach to quantum trajectories. (Doctoral Dissertation). University of Auckland. Retrieved from http://hdl.handle.net/2292/3106

Chicago Manual of Style (16^th Edition):

de Oliveira, Felipe Dimer. “Study of the Dicke model: from phase space approach to quantum trajectories.” 2008. Doctoral Dissertation, University of Auckland. Accessed February 28, 2020. http://hdl.handle.net/2292/3106.

MLA Handbook (7^th Edition):

de Oliveira, Felipe Dimer. “Study of the Dicke model: from phase space approach to quantum trajectories.” 2008. Web. 28 Feb 2020.

Vancouver:

de Oliveira FD. Study of the Dicke model: from phase space approach to quantum trajectories. [Internet] [Doctoral dissertation]. University of Auckland; 2008. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/2292/3106.

Council of Science Editors:

de Oliveira FD. Study of the Dicke model: from phase space approach to quantum trajectories. [Doctoral Dissertation]. University of Auckland; 2008. Available from: http://hdl.handle.net/2292/3106

Louisiana State University

26. Plick, William Nicholas. Quantum light for quantum technologies.

Degree: PhD, Physical Sciences and Mathematics, 2010, Louisiana State University

URL: etd-04192010-140026 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1032

► In this thesis we will theoretically investigate three potentially useful physical systems, after first developing the theoretical framework necessary for studying them. First, we will… (more)

Subjects/Keywords: metrology; quantum optics; lithography; quantum

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APA (6^th Edition):

Plick, W. N. (2010). Quantum light for quantum technologies. (Doctoral Dissertation). Louisiana State University. Retrieved from etd-04192010-140026 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1032

Chicago Manual of Style (16^th Edition):

Plick, William Nicholas. “Quantum light for quantum technologies.” 2010. Doctoral Dissertation, Louisiana State University. Accessed February 28, 2020. etd-04192010-140026 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1032.

MLA Handbook (7^th Edition):

Plick, William Nicholas. “Quantum light for quantum technologies.” 2010. Web. 28 Feb 2020.

Vancouver:

Plick WN. Quantum light for quantum technologies. [Internet] [Doctoral dissertation]. Louisiana State University; 2010. [cited 2020 Feb 28]. Available from: etd-04192010-140026 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1032.

Council of Science Editors:

Plick WN. Quantum light for quantum technologies. [Doctoral Dissertation]. Louisiana State University; 2010. Available from: etd-04192010-140026 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1032

Louisiana State University

27. Roy Bardhan, Bhaskar. Topics in Quantum Metrology, Control, and Communications.

Degree: PhD, Physical Sciences and Mathematics, 2014, Louisiana State University

URL: etd-10052014-073714 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3752

► Noise present in an environment has significant impacts on a quantum system affecting properties like coherence, entanglement and other metrological features of a quantum state.… (more)

▼ Noise present in an environment has significant impacts on a quantum system affecting properties like coherence, entanglement and other metrological features of a quantum state. In this dissertation, we address the effects of different types of noise that are present in a communication channel (or medium) and an interferometric setup, and analyze their effects in the contexts of preserving coherence and entanglement, phase sensitivity, and limits on rate of communication through noisy channels. We first consider quantum optical phase estimation in quantum metrology when phase fluctuations are introduced in the system by its interaction with a noisy environment. By considering path-entangled dual-mode photon Fock states in a Mach-Zehnder optical interferometric configuration, we show that such phase fluctuations affect phase sensitivity and visibility by adding noise to the phase to be estimated. We also demonstrate that the optimal detection strategy for estimating a phase in the presence of such phase noise is provided by the parity detection scheme. We then investigate the random birefringent noise present in an optical fiber affecting the coherence properties of a single photon polarization qubit propagating through it. We show that a simple but effective control technique, called dynamical decoupling, can be used to suppress the effects of the dephasing noise, thereby preserving its ability to carry the encoded quantum information in a long-distance optical fiber communication system. Optical amplifiers and attenuators can also add noise to an entangled quantum system, deteriorating the non-classical properties of the state. We show this by considering a two-mode squeezed vacuum state, which is a Gaussian entangled state, propagating through a noisy medium, and characterizing the loss of entanglement in the covariance matrix and the symplectic formalism for this state. Finally, we discuss limits on the rate of communication in the context of sending messages through noisy optical quantum communication channels. In particular, we prove that a strong converse theorem holds under a maximum photon number constraint for these channels, guaranteeing that the success probability in decoding the message vanishes in the asymptotic limit for the rate exceeding the capacity of the channels.

Subjects/Keywords: Quantum optics; Quantum information theory

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APA (6^th Edition):

Roy Bardhan, B. (2014). Topics in Quantum Metrology, Control, and Communications. (Doctoral Dissertation). Louisiana State University. Retrieved from etd-10052014-073714 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3752

Chicago Manual of Style (16^th Edition):

Roy Bardhan, Bhaskar. “Topics in Quantum Metrology, Control, and Communications.” 2014. Doctoral Dissertation, Louisiana State University. Accessed February 28, 2020. etd-10052014-073714 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3752.

MLA Handbook (7^th Edition):

Roy Bardhan, Bhaskar. “Topics in Quantum Metrology, Control, and Communications.” 2014. Web. 28 Feb 2020.

Vancouver:

Roy Bardhan B. Topics in Quantum Metrology, Control, and Communications. [Internet] [Doctoral dissertation]. Louisiana State University; 2014. [cited 2020 Feb 28]. Available from: etd-10052014-073714 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3752.

Council of Science Editors:

Roy Bardhan B. Topics in Quantum Metrology, Control, and Communications. [Doctoral Dissertation]. Louisiana State University; 2014. Available from: etd-10052014-073714 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3752

University of Victoria

28. Cao, Jieming. Synthesis and characterization of lead-based core-shell-shell quantum dots and studies on excitation-dependent quantum yield measurement.

Degree: Department of Chemistry, 2015, University of Victoria

URL: http://hdl.handle.net/1828/6417

► Nano-sized semiconductors, known as quantum dots (QDs), are one of the hottest research areas in recent years. The energy gaps of QDs change with their… (more)

▼ Nano-sized semiconductors, known as quantum dots (QDs), are one of the hottest research areas in recent years. The energy gaps of QDs change with their diameters, giving them size-dependent optical properties. By controlling reaction conditions, people are able to make QDs that can emit in certain wavelength ranges. So far, QDs have shown great potential in telecommunication, bio-imaging, single-photon laser source, etc. This thesis starts with Chapter 1, which first introduces the finding of QDs and why they have such special properties. The quantum confinement and energy gap are discussed, followed by the absorption and emission of QDs. Moreover, the synthesis methods and mechanism involved are reviewed in brief. Chapter 2 presents the synthesis of lead-based core, core-shell and core-shell-shell QDs and previous work by other people. A few techniques including transmission electron microscopy (TEM), UV-absorption, photoluminescence (PL) measurement, and X-ray photoelectron spectroscopy (XPS) were used and shown in this chapter. Core-shell and core-shell-shell QDs are shown to present excellent stability over 20 months. The ZnS shell was proved by energy-dependent XPS and TEM measurements. A detailed discussion on quantum yield (QY) is given in Chapter 3. Absolute and relative QY measurements and some standard dyes are discussed. After that, Chapter 4 shows systematic QY measurements on lead-based core and core-shell QDs. For each type of QDs, at least two batches are selected with their emission spectra presented as well. It is revealed by collected data that they have excitation-dependent QYs. The QY drops as the excitation light increases in energy (higher wavelength), which is due to non-radiative decays from higher excited states or the Auger effects. QY of PbS and PbSe QDs can be as high as 50%. Eventually, the conclusion and future work are included in Chapter 5. All experimental work is described in detail in the experimental section. Advisors/Committee Members: van Veggel, Frank C.J.M. (supervisor).

Subjects/Keywords: Quantum dot; Quantum yield

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APA (6^th Edition):

Cao, J. (2015). Synthesis and characterization of lead-based core-shell-shell quantum dots and studies on excitation-dependent quantum yield measurement. (Masters Thesis). University of Victoria. Retrieved from http://hdl.handle.net/1828/6417

Chicago Manual of Style (16^th Edition):

Cao, Jieming. “Synthesis and characterization of lead-based core-shell-shell quantum dots and studies on excitation-dependent quantum yield measurement.” 2015. Masters Thesis, University of Victoria. Accessed February 28, 2020. http://hdl.handle.net/1828/6417.

MLA Handbook (7^th Edition):

Cao, Jieming. “Synthesis and characterization of lead-based core-shell-shell quantum dots and studies on excitation-dependent quantum yield measurement.” 2015. Web. 28 Feb 2020.

Vancouver:

Cao J. Synthesis and characterization of lead-based core-shell-shell quantum dots and studies on excitation-dependent quantum yield measurement. [Internet] [Masters thesis]. University of Victoria; 2015. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/1828/6417.

Council of Science Editors:

Cao J. Synthesis and characterization of lead-based core-shell-shell quantum dots and studies on excitation-dependent quantum yield measurement. [Masters Thesis]. University of Victoria; 2015. Available from: http://hdl.handle.net/1828/6417

29. Pitalúa-García, Damián. Quantum information, Bell inequalities and the no-signalling principle.

Degree: PhD, 2014, University of Cambridge

URL: https://www.repository.cam.ac.uk/handle/1810/245205 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.600535

► This PhD thesis contains a general introduction and three main chapters. Chapter 2 investigates Bell inequalities that generalize the CHSH and Braunstein-Caves inequalities. Chapter 3… (more)

▼ This PhD thesis contains a general introduction and three main chapters. Chapter 2 investigates Bell inequalities that generalize the CHSH and Braunstein-Caves inequalities. Chapter 3 shows a derivation of an upper bound on the success probability of a class of quantum teleportation protocols, denoted as port-based teleportation, from the no-cloning theorem and the no-signalling principle. Chapter 4 introduces the principle of quantum information causality. Chapter 2 considers the predictions of quantum theory and local hidden variable theories (LHVT) for the correlations obtained by measuring a pair of qubits by projections defined by randomly chosen axes separated by a given angle θ. The predictions of LHVT correspond to binary colourings of the Bloch sphere with antipodal points oppositely coloured. We show a Bell inequality for all θ, which generalizes the CHSH and the Braunstein-Caves inequalities in the sense that the measurement choices are not restricted to be in a finite set, but are constrained only by the angle θ. We motivate and explore the hypothesis that for a continuous range of θ > 0, the maximum correlation (anticorrelation) is obtained by assigning to one qubit the colouring with one hemisphere black and the other white, and assigning the same (reverse) colouring to the other qubit. We describe numerical tests that are consistent with this hypothesis and bound the range of θ. Chapter 3 shows a derivation of an upper bound on the success probability of port-based teleportation from the no-cloning theorem and the no-signalling principle. Chapter 4 introduces the principle of quantum information causality, a quantum version of the information causality principle. The quantum information causality principle states the maximum amount of quantum information that a transmitted quantum system can communicate as a function of its dimension, independently of any quantum physical resources previously shared by the communicating parties. These principles reduce to the no-signalling principle if no systems are transmitted. We present a new quantum information task, the quantum information causality game, whose success probability is upper bounded by the new principle, and show that an optimal strategy to perform it combines the quantum teleportation and superdense coding protocols with a task that has classical inputs.

Subjects/Keywords: 530.12; Quantum information; Quantum foundations

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APA (6^th Edition):

Pitalúa-García, D. (2014). Quantum information, Bell inequalities and the no-signalling principle. (Doctoral Dissertation). University of Cambridge. Retrieved from https://www.repository.cam.ac.uk/handle/1810/245205 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.600535

Chicago Manual of Style (16^th Edition):

Pitalúa-García, Damián. “Quantum information, Bell inequalities and the no-signalling principle.” 2014. Doctoral Dissertation, University of Cambridge. Accessed February 28, 2020. https://www.repository.cam.ac.uk/handle/1810/245205 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.600535.

MLA Handbook (7^th Edition):

Pitalúa-García, Damián. “Quantum information, Bell inequalities and the no-signalling principle.” 2014. Web. 28 Feb 2020.

Vancouver:

Pitalúa-García D. Quantum information, Bell inequalities and the no-signalling principle. [Internet] [Doctoral dissertation]. University of Cambridge; 2014. [cited 2020 Feb 28]. Available from: https://www.repository.cam.ac.uk/handle/1810/245205 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.600535.

Council of Science Editors:

Pitalúa-García D. Quantum information, Bell inequalities and the no-signalling principle. [Doctoral Dissertation]. University of Cambridge; 2014. Available from: https://www.repository.cam.ac.uk/handle/1810/245205 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.600535

University of Waterloo

30. Alexander, Matthew. A Polar Decomposition for Quantum Channels: Theory and Applications.

Degree: 2019, University of Waterloo

URL: http://hdl.handle.net/10012/14931

► Every potential benefit of quantum computers would be lost without methods to protect the computations from error. Quantum channels provide a framework for understanding error… (more)

Subjects/Keywords: quantum theory; quantum computers

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APA (6^th Edition):

Alexander, M. (2019). A Polar Decomposition for Quantum Channels: Theory and Applications. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/14931

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Alexander, Matthew. “A Polar Decomposition for Quantum Channels: Theory and Applications.” 2019. Thesis, University of Waterloo. Accessed February 28, 2020. http://hdl.handle.net/10012/14931.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Alexander, Matthew. “A Polar Decomposition for Quantum Channels: Theory and Applications.” 2019. Web. 28 Feb 2020.

Vancouver:

Alexander M. A Polar Decomposition for Quantum Channels: Theory and Applications. [Internet] [Thesis]. University of Waterloo; 2019. [cited 2020 Feb 28]. Available from: http://hdl.handle.net/10012/14931.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Alexander M. A Polar Decomposition for Quantum Channels: Theory and Applications. [Thesis]. University of Waterloo; 2019. Available from: http://hdl.handle.net/10012/14931

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Open Access Theses and Dissertations