Дисертації з теми "Quantum Optics and Quantum Information"
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Pope, Damian. "Contrasting quantum mechanics to local hidden variables theories in quantum optics and quantum information science /." [St. Luica, Qld.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16765.pdf.
Повний текст джерелаMichelberger, Patrick Steffen. "Room temperature caesium quantum memory for quantum information applications." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:19c9421d-0276-4c6d-a641-7640d2981da3.
Повний текст джерелаReina, Estupin̄án John-Henry. "Quantum information processing in nanostructures." Thesis, University of Oxford, 2002. http://ora.ox.ac.uk/objects/uuid:6375c7c4-ecf6-4e88-a0f5-ff7493393d37.
Повний текст джерелаHessmo, Björn. "Quantum optics in constrained geometries." Doctoral thesis, Uppsala University, Department of Quantum Chemistry, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1208.
Повний текст джерелаWhen light exhibits particle properties, and when matter exhibits wave properties quantum mechanics is needed to describe physical phenomena.
A two-photon source produces nonmaximally entangled photon pairs when the source is small enough to diffract light. It is shown that diffraction degrades the entanglement. Quantum states produced in this way are used to probe the complementarity between path information and interference in Young's double slit experiment.
When two photons have a nonmaximally entangled polarization it is shown that the Pancharatnam phase is dependent on the entanglement in a nontrivial way. This could be used for implementing simple quantum logical circuits.
Magnetic traps are capable of holding cold neutral atoms. It is shown that magnetic traps and guides can be generated by thin wires etched on a surface using standard nanofabrication technology. These atom chips can hold and manipulate atoms located a few microns above the surface with very high accuracy. The potentials are very versatile and allows for highly complex designs, one such design implemented here is a beam splitter for neutral atoms. Interferometry with these confined de Broglie is also considered. These atom chips could be used for implementing quantum logical circuits.
Devitt, Simon John. "Quantum information engineering : concepts to quantum technologies /." Connect to thesis, 2007. http://eprints.unimelb.edu.au/archive/00003925.
Повний текст джерелаKaiser, Florian. "Photonic entanglement engineering for quantum information applications and fundamental quantum optics." Nice, 2012. https://tel.archives-ouvertes.fr/tel-00777002.
Повний текст джерелаThe aim of this thesis is to develop sources of photonic entanglement to study both quantum networking tasks and some of the foundations of quantum physics. To this end, three high-performance sources are developed, each of them taking extensively advantage of standard telecom fibre optics components. The first source generates polarization entanglement via deterministic pair separation in two adjacent telecommunication channels. This source is naturally suitable for quantum cryptography in wavelength multiplexed network structures. The second source generates for the first time a cross time-bin entangled bi-photon state which allows for quantum key distribution tasks using only passive analyzers. The third source generates, with a record efficiency, polarization entanglement using an energy-time to polarization entanglement transcriber. The photon spectral bandwidth can be chosen over more than five orders of magnitude (25 MHz - 4 THz). This permits implementing the source into existing telecom networks, but also in advanced quantum relay and quantum memory applications. Moreover, this source is used to revisit Bohr’s single-photon wave-particle complementarity notion via employing a Mach-Zehnder interferometer with an output quantum beam-splitter in a true superposition of being present and absent. Finally, to adapt the wavelength of the entangled telecom photon pairs to the absorption wavelength of current quantum memories, a coherent wavelength converter is presented and discussed
McKeever, Jason Terence Taylor Kimble H. Jeff. "Trapped atoms in cavity QED for quantum optics and quantum information /." Diss., Pasadena, Calif. : California Institute of Technology, 2004. http://resolver.caltech.edu/CaltechETD:etd-06032004-163753.
Повний текст джерелаLoock, Peter van. "Quantum communication with continuous variables." Thesis, Bangor University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368766.
Повний текст джерелаZhang, Zheshen. "New techniques for quantum communication systems." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42843.
Повний текст джерелаJenkins, Stewart David. "Theory of light -atomic ensemble interactions entanglement, storage, and retrieval /." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-09252006-175848/.
Повний текст джерелаKennedy, T. A. Brian, Committee Chair ; Kuzmich, Alex, Committee Member ; Chapman, Michael S., Committee Member ; Raman, Chandra, Committee Member ; Morley, Thomas D., Committee Member.
Humphreys, Peter Conway. "Experimental and theoretical techniques for quantum-enhanced metrology and optical quantum information processing." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:57e942ac-f6f1-43fe-ac77-ef85b7db85ca.
Повний текст джерелаLe, Jeannic Hanna. "Optical Hybrid Quantum Information processing." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066596/document.
Повний текст джерелаIn quantum information science and technology, two traditionally-separated ways of encoding information coexist -the continuous and the discrete approaches, resulting from the wave-particle duality of light. The first one is based on quadrature components, while the second one involves single photons. The recent optical hybrid approach aims at using both discrete and continuous concepts and toolboxes to overcome the intrinsic limitations of each field. In this PhD work, first, we use hybrid protocols in order to realize the quantum state engineering of various non-Gaussian states of light. Based on optical parametric oscillators and highly-efficient superconducting-nanowire single-photon detectors, we demonstrate the realization of a high-brightness single-photon source and the quantum state engineering of large optical Schrödinger cat states, which can be used as a continuous-variable qubit. We show how continuous-variable operations such as squeezing can help in this generation. This method based on so-called core states also enables to generate cat states that are more robust to decoherence. Second, in the context of heterogeneous networks based on both encodings, bridging the two worlds by a quantum link requires hybrid entanglement of light. We introduce optical hybrid entanglement between qubits and qutrits of continuous and discrete types, and demonstrate as a first application the remote state preparation of continuous-variable qubits. Our experiment is also a versatile platform to study squeezing-induced micro-macro entanglement
Chaudhury, Souma. "Quantum Control and Quantum Chaos in Atomic Spin Systems." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/195449.
Повний текст джерелаMaurer, Peter. "Coherent control of diamond defects for quantum information science and quantum sensing." Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11431.
Повний текст джерелаPhysics
Oza, Neal N. "Engineering Photonic Switches for Quantum Information Processing." Thesis, Northwestern University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3669298.
Повний текст джерелаIn this dissertation, we describe, characterize, and demonstrate the operation of a dual-in, dual-out, all-optical, fiber-based quantum switch. This "cross-bar" switch is particularly useful for applications in quantum information processing because of its low-loss, high-speed, low-noise, and quantum-state-retention properties.
Building upon on our lab's prior development of an ultrafast demultiplexer [1-3] , the new cross-bar switch can be used as a tunable multiplexer and demultiplexer. In addition to this more functional geometry, we present results demonstrating faster performance with a switching window of ≈45 ps, corresponding to >20-GHz switching rates. We show a switching fidelity of >98%, i. e., switched polarization-encoded photonic qubits are virtually identical to unswitched photonic qubits. We also demonstrate the ability to select one channel from a two-channel quantum data stream with the state of the measured (recovered) quantum channel having >96% relative fidelity with the state of that channel transmitted alone. We separate the two channels of the quantum data stream by 155 ps, corresponding to a 6.5-GHz datastream.
Finally, we describe, develop, and demonstrate an application that utilizes the switch's higher-speed, lower-loss, and spatio-temporal-encoding features to perform quantum state tomographies on entangled states in higher-dimensional Hilbert spaces. Since many previous demonstrations show bipartite entanglement of two-level systems, we define "higher" as d > 2 where d represents the dimensionality of a photon. We show that we can generate and measure time-bin-entangled, two-photon, qutrit (d = 3) and ququat (d = 4) states with >85% and >64% fidelity to an ideal maximally entangled state, respectively. Such higher-dimensional states have applications in dense coding [4] , loophole-free tests of nonlocality [5] , simplifying quantum logic gates [6] , and increasing tolerance to noise and loss for quantum information processing [7] .
Menzies, David. "Procrustean entanglement concentration, weak measurements and optimized state preparation for continuous-variable quantum optics." Thesis, St Andrews, 2009. http://hdl.handle.net/10023/739.
Повний текст джерелаKok, Pieter. "State preparation and some applications in quantum optics within the context of quantum information theory." Thesis, Bangor University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327425.
Повний текст джерелаRådmark, Magnus. "Photonic quantum information and experimental tests of foundations of quantum mechanics." Doctoral thesis, Stockholms universitet, Fysikum, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-37464.
Повний текст джерелаSansavini, Francesca. "Quantum information protocols in complex entangled networks." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18512/.
Повний текст джерелаMetcalf, Benjamin James. "Silica-on-silicon waveguide circuits and superconducting detectors for integrated quantum information processing." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:8b5482f6-93a7-4d6e-b335-ba258ad3de1e.
Повний текст джерелаCroal, Callum. "Quantum correlations in continuous variable mixed states : from discord to signatures." Thesis, University of St Andrews, 2016. http://hdl.handle.net/10023/8969.
Повний текст джерелаMatthews, Jonathan C. F. "Multi-photon quantum information science and technology in integrated optics." Thesis, University of Bristol, 2011. http://hdl.handle.net/1983/9199e590-ef8b-4a6f-b032-507b0960adc4.
Повний текст джерелаCooper, Merlin Frederick Wilmot. "Measurement and manipulation of quantum states of travelling light fields." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:79164748-ebb3-48e2-b4d4-1a4766d29217.
Повний текст джерелаSchafer, Joachim. "Information transmission through bosonic gaussian channels." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209420.
Повний текст джерелаWe focus in this work mainly on the Gaussian capacity for the following reasons. First, Gaussian encodings are easily accessible experimentally. Second, the difficulty of studying the classical capacity, which arises due to an optimization problem in an infinite dimensional Hilbert space, is greatly reduced when considering only Gaussian input encodings. Third, the Gaussian capacity is conjectured to coincide with the classical capacity, even though this longstanding conjecture is unsolved until today.
We start with the investigation of the capacities of the single-mode Gaussian channel. We show that the most general case can be reduced to a simple, fiducial Gaussian channel which depends only on three parameters: its transmissivity (or gain), the added noise variance and the squeezing of the noise. Above a certain input energy threshold, the optimal input variances are given by a quantum water-filling solution, which implies that the optimal modulated output state is a thermal state. This is a quantum extension (or generalization) of the well-known classical water-filling solution for parallel Gaussian channels. Below the energy threshold the solution is given by a transcendental equation and only the less noisy quadrature is modulated. We characterize in detail the dependence of the Gaussian capacity on its channel parameters. In particular, we show that the Gaussian capacity is a non-monotonous function of the noise squeezing and analytically specify the regions where it exhibits one maximum, a maximum and a minimum, a saddle point or no extrema.
Then, we investigate the case of n-mode channels with noise correlations (i.e. memory), where we focus in particular on the classical additive noise channel. We consider memory models for which the noise correlations can be unraveled by a passive symplectic transformation. Therefore, we can simplify the problem to the study of the Gaussian capacity in an uncorrelated basis, which corresponds to the Gaussian capacity of n single-mode channels with a common input energy constraint. Above an input energy threshold the solutions is given by a global quantum water-filling solution, which implies that all modulated single-mode output states are thermal states with the same temperature. Below the threshold the channels are divided into three sets: i) those that are excluded from information transmission, ii) those for which only the less noisy quadrature is modulated, and iii) those for which the quantum water-filling solution is satisfied. As an example we consider a Gauss-Markov correlated noise, which in the uncorrelated basis corresponds to a collection of single-mode classical additive noise channels. When rotating the collection of optimal single-mode input states back to the original, correlated basis the optimal multi-mode input state becomes a highly entangled state. We then compare the performance of the optimal input state with a simple coherent state encoding and conclude that one gains up to 10% by using the optimal encoding.
Since the preparation of the optimal input state may be very challenging we consider sub-optimal Gaussian-matrix product states (GMPS) as input states as well. GMPS have a known experimental setup and, though being heavily entangled, can be generated sequentially. We demonstrate that for the Markovian correlated noise as well as for a non-Markovian noise model in a wide range of channel parameters, a nearest-neighbor correlated GMPS achieves more than 99.9% of the Gaussian capacity. At last, we introduce a new noise model for which the GMPS is the exact optimal input state. Since GMPS are known to be ground states of quadratic Hamiltonians this suggests a starting point to develop links between optimization problems of quantum communication and many body physics.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Ray, Megan. "Verifying Optical Entanglement." Thesis, University of Oregon, 2013. http://hdl.handle.net/1794/13430.
Повний текст джерелаCai, Yin. "Quantum coherent control with an optical frequency comb." Thesis, Paris, Ecole normale supérieure, 2015. http://www.theses.fr/2015ENSU0030/document.
Повний текст джерелаMultimode squeezing plays an essential role in quantum informationprocessing and quantum metrology. Using optical frequency combs,we generate multi-temporal-mode state from a synchronouslypumped optical parametric oscillator (SPOPO). An on-demandquantum network simulator is developed using the SPOPO andultrafast pulse shaping; up-to-twelve-node cluster states and asix-partite quantum secret sharing protocol are experimentallyemulated with this simulator. Furthermore, frequency resolvedmultipixel detectors are employed, and used to realize aline-shape-eight-node cluster state. We also developed a multimodequantum spectrometer, which is able to exceed the standardquantum limit for measuring manifold parameters of ultrafast pulses
Leedumrongwatthanakun, Saroch. "Quantum information processing with a multimode fibre." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS526.
Повний текст джерелаTransport of information through a multimode optical fibre raises challenges when one wants to increase the data traffic using many spatial modes due to modal cross-talk and dispersion. Instead of considering those complex mixing of modes as a detrimental process, in this dissertation, we harness its mode mixing to process quantum optical information. We implement a reconfigurable linear optical network, a fundamental building block for scalable quantum technologies, based on an inverse photonic approach exploiting the technology of wavefront shaping. We experimentally demonstrate manipulation of two-photon quantum interference on various linear optical networks across both spatial and polarization degrees of freedom. In particular, we experimentally show the zero-transmission law in Fourier and Sylvester interferometers, which are used to certificate the degree of indistinguishability of an input state. Moreover, thanks to the ability to implement a non-unitary network, we observe the photon anti-coalescence effect in all output configurations, as well as the realization of a tunable coherent absorption experiment. Therefore, we demonstrate the reconfigurability, accuracy, scalability and robustness of the implemented linear optical networks for quantum information processing. Furthermore, we study the statistical properties of one-and two-photon speckles generated from various ground-truth states of light after propagating through a multimode fibre. These statistical properties of speckles can be used to extract information about the dimensionality, purity, and indistinguishability of an unknown input state of light, therefore allowing for state classification. Our results highlight the potential of complex media combined with wavefront shaping for quantum information processing
Arzani, Francesco. "Measurement based quantum information with optical frequency combs." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEE005/document.
Повний текст джерелаThe present manuscript reports theoretical investigations about the use of recently developed experimental techniques in the realization of quantum information protocols with continuous variables. The focus of the work is on the multi-mode Gaussian states produced by spontaneous parametric down-conversion of optical frequency combs. Such setup allows to deterministicallyengineer many different Gaussian states of light. The output state can be de-Gaussified subtracting or adding a photon coherently on a superposition of modes and finally measured with pulse-shaped and wavelength-multiplexed homodyne detection. The thesis encompasses three projects. The first concerns the optimization of the spectrum of the pump laser field to engineer the Gaussian output state. We developed mathematical techniques to treat spectral profiles with arbitrary amplitude and spectral phase. We thenran an optimization algorithm to find the spectra maximizing several interesting properties of the state of the down-converted field. A particular emphasis was put on the production of continuous-variable cluster states. The optimizations were developed in such a way as to ensure the experimental feasibility of the optimized pump spectra. In the second project we studied how the non-Gaussian states produced subtracting a photon from a squeezed state can be used for quantum computation. We propose a protocol inspired by the measurement-based paradigm for quantum computation combining the photon subtracted states and homodyne detectionto approximate unitary non-Gaussian operations. We show that the same results can be obtained with projective measurements onsingle-photon states. Finally, the third project deals with quantum secret sharing. In quantum secret sharing schemes a dealer wants to share information encoded in some quantum system with a group of players in such a way that subsets of players need to collaborate if they want to retrieve the information. We devised a secret sharing protocol that could be mapped to the experimental setups developed in our group and participated in the formulation of an experimental proof of principle of such protocol. Starting from this we derived general results for sharing and reconstructing arbitrary quantum states using Gaussian resources
Buzbee, Michael Laurence. "3-Dimensional Photonic Circuits for Quantum Information Processing." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1461970290.
Повний текст джерелаDonati, Gaia. "Hybrid quantum information processing with continuous and discrete variables of light fields." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:673338dc-1233-43c8-be93-11b748a428a9.
Повний текст джерелаSariyanni, Zoe-Elizabeth. "Coherent effects in atomic and molecular media: applications to anthrax detection and quantum information." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4242.
Повний текст джерелаGullans, Michael John. "Controlling Atomic, Solid-State and Hybrid Systems for Quantum Information Processing." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11146.
Повний текст джерелаPhysics
Quinn, Niall. "Gaussian non-classical correlations in bipartite dissipative continuous variable quantum systems." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/6915.
Повний текст джерелаShih, Chung-Yu. "Characterizing single atom dipole traps for quantum information applications." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47607.
Повний текст джерелаDjordjevic, Ivan B. "Integrated Optics Modules Based Proposal for Quantum Information Processing, Teleportation, QKD, and Quantum Error Correction Employing Photon Angular Momentum." IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2016. http://hdl.handle.net/10150/615122.
Повний текст джерелаClark, Alex S. "Quantum information processing in optical fibres." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557975.
Повний текст джерелаAmselem, Elias. "Dynamics of Quantum Correlations with Photons : Experiments on bound entanglement and contextuality for application in quantum information." Doctoral thesis, Stockholms universitet, Fysikum, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-66469.
Повний текст джерелаAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 5: Submitted. Paper 6: Submitted.
Thomas-Peter, Nicholas. "Quantum enhanced precision measurement and information processing with integrated photonics." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:7bd47582-d32f-4d07-9e90-4978c32cf14e.
Повний текст джерелаHameedi, Muhammad Alley. "Single Photon Sources and Single Quantum System enabled Communication." Doctoral thesis, Stockholms universitet, Fysikum, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-139095.
Повний текст джерелаAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript. Paper 5: Manuscript.
Jen, Hsiang-Hua. "Theory of light-matter interactions in cascade and diamond type atomic ensembles." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37288.
Повний текст джерелаThomas, Peter James. "The application of spontaneous parametric downconversion to develop tools for validating photonic quantum information technologies." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/3050.
Повний текст джерелаRakreungdet, Worawarong. "Quantum Information Science with Neutral Atoms." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/194406.
Повний текст джерелаFabre, Nicolas. "Quantum information in time-frequency continuous variables." Thesis, Université de Paris (2019-....), 2020. http://www.theses.fr/2020UNIP7044.
Повний текст джерелаThis thesis tackles the time-frequency continuous variables degree of freedom encoding of single photons and examine the formal mathematical analogy with the quadrature continuous variables of the electromagnetic field. We define a new type of qubit which is robust against time-frequency displacement errors. We define a new double-cylinder phase space which is particularly adapted for states which have a translational symmetry. We also study how to build a functional phase space distribution which allows to describe a quantum state with spectral and quadrature continuous variables degrees of freedom
Reim, Klaus Franz. "Broadband optical quantum memory." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:d0d73ed2-32c2-4de9-8b3d-fcf8b88b22b4.
Повний текст джерелаFlurin, Emmanuel. "The Josephson mixer : a swiss army knife for microwave quantum optics." Thesis, Paris, Ecole normale supérieure, 2014. http://www.theses.fr/2014ENSU0024/document.
Повний текст джерелаThis thesis work explores unique features offered by the Josephson mixer in the upcoming field of microwave quantum optics. We have demonstrated three major roles the Josephson mixer could play in emerging quantum information architectures. First, we have designed and fabricated a state-of-the-art practical quantum limited amplifier with the best quantum efficiency achieved to date. This tool is crucial for probing mesoscopic systems with microwaves, and in particular superconducting circuits. Hence, it has enabled us to realize successfully the stabilization of quantum trajectories of a superconducting qubit by measurement-based feedback. Second, we have shown how this circuit can generate and distribute entangled microwave radiations on separated transmission lines at different frequencies. Using two Josephson mixers, we have provided the first demonstration of entanglement between spatially separated propagating fields in the microwave domain, the so-called Einstein-Podolsky-Rosen states. Finally, we have used the Josephson mixer as a frequency converter. Acting as a switch, it is able to dynamically turn on and off the coupling to a low loss cavity. This feature allowed us to realize a quantum memory for microwaves. In combination with the ability to generate entanglement, we have measured the time-controlled generation, storage and on-demand release of an entangled state, which is a prerequisite for nodes of a quantum network
Zimmer, Frank E. "Matter-wave optics of dark-state polaritons applications to interferometry and quantum information /." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982522533.
Повний текст джерелаGibbons, Michael J. "Robust, reusable qubits for quantum information applications." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39474.
Повний текст джерелаViscor, Pagès Daniel. "From quantum memories to single-site addressing with three-level atoms." Doctoral thesis, Universitat Autònoma de Barcelona, 2013. http://hdl.handle.net/10803/117482.
Повний текст джерелаQuantum information science, which emerges from the combination of information theory and quantum physics, has experienced an enormous progress during the last decades, leading to revolutionary advances in a wide range of interdisciplinary fields, such as quantum computation, quantum communication, high precision measurements, and fundamental quantum science. However, the ambitious goals at which the scientific community aim, e.g., quantum criptography, quantum simulators, or even quantum computation, have only started to stand out.In most quantum information applications, atomic ensembles are normally used to store and process the information, while light is used as a tool to manipulate and perform logical operations, as well as to transmit the quantum bits between distant nodes of a quantum network. Thus, the realization of a suitable quantum interface between light and atomic ensembles is essential in quantum information science. Regarding light-matter interaction, one of the most relevant systems are three-level atoms in interaction with a pair of electromagnetic fields. Three-level systems exhibit a rich variety of phenomena due to quantum interferences between the two absorption paths for the light. These quantum interferences lead, for instance, to coherent population trapping, electromagnetically induced transparency, or stimulated Raman adiabatic passage, which have found applications in many areas of quantum information. This thesis, which collects the research work that I have performed during my PhD under the guidance and support of my supervisors and collaborators, is mainly focused in quantum information applications using three level atoms in interaction with electromagnetic fields both at the semiclassical and fully quantum levels. The first three chapters of the work are focused on the theoretical study of novel methods to implement quantum memories for single photon qubits in superposition of two components, either polarization or frequency. Quantum memories are devices capable of storing and retrieving on demand quantum states of light with high efficiency and fidelity, and are essential components in many quantum information applications, such as quantum repeaters or single photon sources. Thus, the study of methods to store different kinds of quantum information encoding in photons is an essential task.Moreover, additional work in quantum information processing done during my PhD is collected in the final chapters. In particular, first we focus on the problem of single site addressing of ultracold neutral atoms in optical lattices with one atom per site, by using a position selective adiabatic passage technique. Next, we extend a theoretical model capable of providing reliable predictions for the production of controlled bandwidth and pure single photon pairs experiment, using a spontaneous parametric down-conversion setup.
Domeneguetti, Renato Ribeiro. "Ruídos quânticos da luz em macro cavidade de fibra óptica." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-26092014-152240/.
Повний текст джерелаNondegenarate four-wave mixing in an optical-fiber cavity geometry, was initially proposed as a mean to generate squeezed states of light. We developed in this work a purely quantum analyzis of the nonlinear interaction between light and medium. With Fokker-Planck equation in the Wigner representation, we obtained directly from the equations, the twin beams oscillation threshold and bistability. From the linearized dynamic equations for the quadratures fluctuations, we confirmed the generation of squeezed states proceeding from 4WM process, not only below but above the threshold oscillation. It is not possible to initiate the twin beams generation without first reaching the stimulated Brillouin scattering threshold. Therefore, techniques to increase this threshold, must be used for any noise measure to the shot-noise level with fields generation. We also have tested the technical limitations of laser diode, as amplitude and phase noise, as well as the stability in an interferometric experiment. Below threshold, the cavity acts in the sense of reducing the intrinsic laser phase noise in a frequency range that goes from 10MHz to 80MHz.
Leung, Calvin. "Quantum Foundations with Astronomical Photons." Scholarship @ Claremont, 2017. http://scholarship.claremont.edu/hmc_theses/98.
Повний текст джерела