Dissertations / Theses on the topic 'Quantum computing'
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Zimokos, K. R. "Quantum computing." Thesis, Sumy State University, 2014. http://essuir.sumdu.edu.ua/handle/123456789/45442.
Full textДядечко, Алла Миколаївна, Алла Николаевна Дядечко, Alla Mykolaivna Diadechko, Артем Володимирович Дмітрієв, Артем Владимирович Дмитриев, and Artem Volodymyrovych Dmitriiev. "Quantum computing." Thesis, Видавництво СумДУ, 2010. http://essuir.sumdu.edu.ua/handle/123456789/16434.
Full textNutz, Thomas. "Semiconductor quantum light sources for quantum computing." Thesis, Imperial College London, 2018. http://hdl.handle.net/10044/1/63931.
Full textHeidebrecht, Andreas. "Quantum state engineering for spin quantum computing." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-29410.
Full textStock, Ryan. "Silicon-based quantum optics and quantum computing." Thesis, Cardiff University, 2018. http://orca.cf.ac.uk/111871/.
Full textJohnsen, Sverre Gullikstad. "Towards optical quantum computing." Thesis, Norwegian University of Science and Technology, Department of Physics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2256.
Full textTsampardoukas, Christos. "Ion trap quantum computing." Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/10704.
Full textDuncan, Ross. "Types for quantum computing." Thesis, University of Oxford, 2006. http://ora.ox.ac.uk/objects/uuid:c2901ae8-9386-4dbf-879d-e37bbc2692bd.
Full textWang, Qian. "Quantum tunneling, quantum computing, and high temperature superconductivity." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1638.
Full textMeyer, Carola. "Endohedral fullerenes for quantum computing." [S.l. : s.n.], 2003. http://www.diss.fu-berlin.de/2003/296/index.html.
Full textBresler, Yony. "Stochastic simulations of quantum computing." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106525.
Full textUne méthode pour simuler des circuits de calcul quantique par des processus stochastiques est décrite et analysée. Les circuits sont transformés en une action complexe par laquelle les observables sont calculés. Ces moyennes sont évaluées à l'aide de Monte Carlo et de méthodes complexes de Langevin. La transformation peut être appliquée sur n'importe quel circuit avec un état de produits d'entrée. Celle-ci résulte en équations qui sont polynomiales dans le stockage. Cette méthode est unique, car elle permet une simulation efficace et est à la fois généralisée. Trois circuits d'échantillonnage sont simulés. Les techniques de simulations courantes démontrent inadéquatement les estimations des observables. Une méthode améliorée est donc proposée par l'ajout d'un terme de couplage à l'action pour stabiliser le système. Les résultats démontrés via la méthode améliorée sont plus fiables. La faisabilité et les orientations futures sont discutées.
Metz, Jeremy. "Quantum Computing With Macroscopic Heralding." Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.484422.
Full textCampbell, Earl T. "Distrubuting entanglement for quantum computing." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504315.
Full textNickerson, Naomi. "Practical fault-tolerant quantum computing." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/31475.
Full textWardrop, Matthew Phillip. "Quantum Gates for Quantum Dots." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14938.
Full textXu, Huizhong. "Quantum computing with Josephson junction circuits." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1885.
Full textThesis research directed by: Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Evans, Julia. "The algebra of topological quantum computing." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107687.
Full textLe calcul quantique topologique est une approche au problème d'implementationde circuits quantique d'une façon robuste et precisé. L'idée s'agit d'exploiter certaines propriétés de quasiparticules, dites "anyons", pour obtenir une implémentation du calcul quantique qui est intrinsequement tolerante aux pannes. La structure mathématique qui décrit ces anyons est celle des catégories modulaires. Ces objets peuvent être construites à partir de représentations de certaines algèbres, appelées groupes quantiques. Dans ce mémoire, nous donnerons une exposition des catégories modulaires, des groupes quantiques et du lien qu'ils partagent avec le calcul quantique. Le mémoire ne devrait requérir qu'une connaissance de base en algèbre et en théorie des categories. L'espoir étant de donner un model concret pour les informaticiens de la théorie de catégories obtenus à partir de groupes quantiques. L'emphase sera sur le point de vu algèbrique et catégorique plutôt que celui physique.
Casson, Ian. "Linking polymetallic rings for quantum computing." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503018.
Full textIoannou, L. M. "Computing finite-dimensional bipartite quantum separability." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.604939.
Full textZhang, Jinying. "Fullerene Compounds for Quantum Computing Architectures." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531661.
Full textPérez, Salinas Adrián. "Algorithmic strategies for seizing quantum computing." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673255.
Full textLa computación cuántica es una tecnología emergente con potencial para resolver problemas hoy impracticables. Para ello son necesarios ordenadores capaces de mantener sistemas cuánticos y controlarlos con precisión. Sin embargo, construir estos ordenadores es complejo y a corto plazo solo habrá ordenadores pequeños afectados por el ruido y sujetos a ruido (NISQ). Para aprovechar los ordenadores NISQ se exploran algoritmos que requieran pocos recursos cuánticos mientras proporcionan soluciones aproximadas a los problemas que enfrentan. En esta tesis se estudian dos propuestas para algoritmos NISQ: re-uploading y unary. Cada estrategia busca tomar ventaja de diferentes características de la computación cuántica para superar diferentes obstáculos. Ambas estrategias son generales y aplicables en diversos escenarios. En primer lugar, re-uploading está diseñado como un puente entre la computación cuántica y el aprendizaje automático (Machine Learning). Aunque no es el primer intento de aplicar la cuántica al aprendizaje automático, re-uploading tiene ciertas características que lo distinguen de otros métodos. En concreto, re-uploading consiste en introducir datos en un algoritmo cuántico en diferentes puntos a lo largo del proceso. Junto a los datos se utilizan también parámetros optimizables clásicamente que permiten al circuito aprender cualquier comportamiento. Los resultados mejoran cuantas más veces se introducen los datos. El re-uploading cuenta con teoremas matemáticos que sustentan sus capacidades, y ha sido comprobado con éxito en diferentes situaciones tanto simuladas como experimentales. La segunda estrategia algorítmica es unary. Consiste en describir los problemas utilizando solo parte del espacio de computación disponible dentro del ordenador. Así, las capacidades computacionales del ordenador no son óptimas, pero a cambio las operaciones necesarias para una cierta tarea se simplifican. Los resultados obtenidos son resistentes al ruido, y mantienen su significado, y se produce una compensación entre eficiencia y resistencia a errores. Los ordenadores NISQ se ven beneficiados de esta situación para problemas pequeños. En esta tesis, unary se utiliza para resolver un problema tíıpico de finanzas, incluso obteniendo ventajas cuánticas en un problema aplicable al mundo real. Con esta tesis se espera contribuir al crecimiento de los algoritmos disponibles para ordenadores cuánticos NISQ y allanar el camino para las tecnologías venideras.
Gimeno-Segovia, Mercedes. "Towards practical linear optical quantum computing." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/43936.
Full textBrown, Katherine Louise. "Using the qubus for quantum computing." Thesis, University of Leeds, 2011. http://etheses.whiterose.ac.uk/1687/.
Full textKult, David. "Quantum Holonomies : Concepts and Applications to Quantum Computing and Interferometry." Doctoral thesis, Uppsala University, Quantum Chemistry, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8185.
Full textQuantum holonomies are investigated in different contexts.
A geometric phase is proposed for decomposition dependent evolution, where each component of a given decomposition of a mixed state evolves independently. It is shown that this geometric phase only depends on the path traversed in the space of decompositions.
A holonomy is associated to general paths of subspaces of a Hilbert space, both discrete and continuous. This opens up the possibility of constructing quantum holonomic gates in the open path setting. In the discrete case it is shown that it is possible to associate two distinct holonomies to a given path. Interferometric setups for measuring both holonomies are
provided. It is further shown that there are cases when the holonomy is only partially defined. This has no counterpart in the Abelian setting.
An operational interpretation of amplitudes of density operators is provided. This allows for a direct interferometric realization of Uhlmann's parallelity condition, and the possibility of measuring the Uhlmann holonomy for sequences of density operators.
Off-diagonal geometric phases are generalized to the non-Abelian case. These off-diagonal holonomies are undefined for cyclic evolution, but must contain members of non-zero rank if all standard holonomies are undefined. Experimental setups for measuring the off-diagonal holonomies are proposed.
The concept of nodal free geometric phases is introduced. These are constructed from gauge invariant quantities, but do not share the nodal point structure of geometric phases and off-diagonal geometric phases. An interferometric setup for measuring nodal free geometric phases is provided, and it is shown that these phases could be useful in geometric quantum computation.
A holonomy associated to a sequence of quantum maps is introduced. It is shown that this holonomy is related to the Uhlmann holonomy. Explicit examples are provided to illustrate the general idea.
Estarellas, Pascual. "Spin chain systems for quantum computing and quantum information applications." Thesis, University of York, 2018. http://etheses.whiterose.ac.uk/20556/.
Full textLovett, Neil Brian. "Application of quantum walks on graph structures to quantum computing." Thesis, University of Leeds, 2011. http://etheses.whiterose.ac.uk/1689/.
Full textDewaele, Nicholas. "Quantum Computing With Quantum Dots Using The Heisenberg Exchange Interaction." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/theses/1600.
Full textHolladay, Robert Tyler. "Steepest-Entropy-Ascent Quantum Thermodynamic Modeling of Quantum Information and Quantum Computing Systems." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/94630.
Full textDoctor of Philosophy
Quantum computers (QCs) have the potential to perform certain tasks much more efficiently than today0 s supercomputers. One primary challenge in realizing a practical QC is maintaining the stored information, the loss of which is known as decoherence. This work attributes decoherence to dissipation (a classical analogue being heat generated due to friction) occurring while an algorithm is run on the QC. Standard quantum modeling approaches assume that for any dissipation to occur, the QC must interact with its environment. However, in this work, steepest-entropy-ascent quantum thermodynamics (SEAQT) is used to model the evolution of the QC as it runs an algorithm. SEAQT, developed by Hatsopolous, Gyftopolous, Beretta, and others over the past 40 years, supplements the laws of quantum mechanics with those of thermodynamics and in contrast to the standard quantum approaches does not require the presence of an environment to account for the dissipation which occurs. This work first applies the SEAQT framework to modeling single qubits (quantum bits) to characterize the effect of dissipation on the information stored on the qubit. This is later extended to a nuclear-magnetic-resonance (NMR) QC of 7 qubits. Additionally, SEAQT is used to predict experimentally observed dissipation in a two-qubit NMR QC. Afterwards, several methods for constrained perturbations of a QC0 s state are presented. These methods are then used with SEAQT to analyze the effect of dissipation on the entanglement of two qubits. Finally, a model is derived within the SEAQT framework accounting for a qubit interacting with its environment, which is at a constant temperature. This model is then used to develop a method for limiting the decoherence and shown to significantly lowering the resulting error due to decoherence.
Pius, Einar. "Parallel quantum computing : from theory to practice." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/15857.
Full textNaydenov, Boris N. "Encapsulation of endohedral fullerenes for quantum computing." [S.l.] : [s.n.], 2006. http://www.diss.fu-berlin.de/2006/659/index.html.
Full textLi, Huidong, and 李輝東. "The reversibility and determinism in quantum computing." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31228306.
Full textRosenberg, Nathanial Owen. "Cryptology Management in a Quantum Computing Era." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/7407.
Full textLee, James. "Photon sources for linear optical quantum computing." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/287474.
Full textCao, Yameng. "Semiconductor light sources for photonic quantum computing." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/56619.
Full textSheldon, Sarah (Sarah Elizabeth). "Second order error correction in quantum computing." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44834.
Full textIncludes bibliographical references (leaf 23).
Error correction codes are necessary for the development of reliable quantum computers. Such codes can prevent the lost of information from decoherence caused by external perturbations. This thesis evaluates a five qubit code for correcting second order bit-flip errors. The code consists of encoding, decoherence, decoding, and error correction steps. This work analyzes the proposed code using geometric algebra methods and examines the state of the system after each step in the process.
by Sarah Sheldon.
S.B.
Kruger, Markus Gustav. "On evolutionary algorithms for effective quantum computing." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20095.
Full textENGLISH ABSTRACT: The goal of this thesis is to present evolutionary algorithms, and demonstrate their applicability in quantum computing. As an introduction to evolutionary algorithms, it is applied to the simple but still challenging (from a computational viewpoint) Travelling Salesman Problem (TSP). This example is used to illustrate the e ect of various parameters like selection method, and maximum population size on the accuracy and e ciency of the evolutionary algorithms. For the sample problem, the 48 continental state capitals of the USA, solutions are evolved and compared to the known optimal solution. From this investigation tournament selection was shown to be the most e ective selection method, and that a population of 200 individuals per generation gave the most e ective convergence rates. In the next part of the thesis, evolutionary algorithms are applied to the generation of optimal quantum circuits for the following cases: The identity transformation : Picked for its simplicity as a test of the correct implementation of the evolutionary algorithm. The results of this investigation showed that the solver program functions correctly and that evolutionary algorithms can indeed nd valid solutions for this kind of problem. The work by Ding et al. [16] on optimal circuits for the two-qubit entanglement gate, controlled-S gate as well as the three qubit entanglement gate are solved by means of EA and the results compared. In all cases similar circuits are produced in fewer generations than the application of Ding et al. [16]. The three qubit quantum Fourier transform gate was also attempted, but no convergence was attained. The quantum teleportation algorithm is also investigated. Firstly the nature of the transformation that leads to quantum teleportation is considered. Next an e ective circuit is sought using evolutionary algorithms. The best result is one gate longer than Brassard [11], and seven gates longer than Yabuki [61].
AFRIKAANSE OPSOMMING: Die doel van hierdie tesis is om evolusionêre algoritmes te ondersoek en hulle toepaslikheid op kwantumkomputasie te demonstreer. As 'n inleiding tot evolusionêre algoritmes is die eenvoudige, maar steeds komputasioneel uitdagende handelsreisigerprobleem ondersoek. Die invloed van die keuse van 'n seleksie metode, sowel as die invloed van die maksimum aantal individue in 'n generasie op die akkuraatheid en e ektiwiteit van die algoritmes is ondersoek. As voorbeeld is die 48 kontinentale hoofstede van die state van die VSA gekies. Die oplossings wat met evolusionêre algoritmes verkry is, is met die bekende beste oplossings vergelyk. Die resultate van hierdie ondersoek was dat toernooi seleksie die mees e ektiewe seleksie metode is, en dat 200 individue per generasie die mees e ektiewe konvergensie tempo lewer. Evolusionêre algoritmes word vervolgens toegepas om optimale oplossings vir die volgende kwantumalgoritmes te genereer: Die identiteitstransformasie: Hierdie geval is gekies as 'n eenvoudige toepassing met 'n bekende oplossing. Die resultaat van hierdie toepassing van die program was dat dit korrek funksioneer, en vinnig by die korrekte oplossings uitkom. Vervolgens is daar ondersoek ingestel na vier van die gevalle wat in Ding et al. [16] bespreek word. Die spesi eke transformasies waarna gekyk is, is 'n optimale stroombaan vir twee kwabis verstrengeling, 'n beheerde-S hek, 'n drie kwabis verstrengelings hek, en 'n drie kwabis kwantum Fourier transform hek. In die eerste drie gevalle stem die oplossings ooreen met die van Ding et al. [16], en is die konvergensie tempo vinniger. Daar is geen oplossing vir die kwantum Fourier transform verkry nie. Laastens is daar na die kwantumteleportasiealgoritme gekyk. Die eerste stap was om te kyk na die transformasie wat in hierdie geval benodig word, en daarna is gepoog om 'n e ektiewe stroombaan te evolueer. Die beste resultaat was een hek langer as Brassard [11], en sewe hekke langer as Yabuki [61].
Shojaei, Borzoyeh. "Antimonide-Based Compound Semiconductors for Quantum Computing." Thesis, University of California, Santa Barbara, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10195560.
Full textQuantum information science has made significant progress over the last several decades, but the eventual form a quantum computer will take has yet to be determined. Several physical systems have been shown to operate as quantum bits, or qubits, but each faces a central challenge: the qubit must be sufficiently isolated from its environment to maintain quantum coherence while simultaneously having sufficient coupling to the environment to allow quantum mechanical interactions for manipulation and measurement. An approach to achieve these conflicting requirements is to create qubits that are insensitive to small perturbing interactions within their environment by using topological properties of the physical system in which the qubits are formed. This dissertation presents studies on low-dimensional semiconductor heterostructures of InAs, GaSb and AlSb fabricated by molecular beam epitaxy with focus on relevant properties for their utilization in forming a topologically protected (TP) qubit.
The theoretical basis regarding the semiconductor characteristics suitable for realizing TP qubits stipulates the need for strong spin-orbit coupled semiconductors with high carrier mobility. A comparative study of InAs/AlSb heterostructures wherein structure parameters were systematically varied led to a greater understanding of the limits to mobility in InAs quantum wells. Magnetotransport measurements using a dual-gated device geometry and a comparison of experiment to models of carrier mobility as a function of carrier density were used to identify dominant scattering mechanisms in these heterostructures.
The development of dual-gated devices and high quality InAs channels with AlSb barriers led to a demonstration of the gate control of spin-orbit coupling in a high mobility InAs/AlSb quantum well in which the gate-tuned electron mobility exceeded 700,000 cm2/V·s. Analysis of low temperature magnetoresistance oscillations indicated the zero field spin-splitting could be tuned via the Rashba effect while keeping the two-dimensional electron gas charge density constant.
Findings from the work on InAs quantum wells were applied to investigations on InAs/GaSb bilayers, a system predicted to be a two-dimensional topological insulator (TI). The temperature and magnetic field dependence of the resistance in dual-gated InAs/GaSb heterostructures gate-tuned to the predicted TI regime were found consistent with conduction through a disordered two-fluid system. The impact of disorder on the formation of topologically protected edge states and an insulating bulk was considered. Potential fluctuations in the band structure for realistic levels of disorder in state-of-the-art heterostructures were calculated using a gated heterostructure model. Potential fluctuations were estimated to be sufficiently large such that conduction in the predicted TI regime was likely dominated by tunneling between localized electron and hole charge fluctuations, corresponding to a symplectic metallic phase rather than a topological insulator. The implications are that future efforts must address defects and disorder in this system if the TI regime is to be achieved.
Al-Latifi, Yasir. "Optimizing numerical modelling of quantum computing hardware." Thesis, Umeå universitet, Institutionen för fysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-182659.
Full textZORZI, Margherita. "Lambda calculi and logics for quantum computing." Doctoral thesis, Università degli Studi di Verona, 2009. http://hdl.handle.net/11562/337380.
Full textIn this thesis we propose several original results about lambda calculi and logics for quantum computing. The work is divided into three parts. The first one is devoted to recall the main notions about linear algebra, logics and quantum computing. The second and main part focalizes on quantum lambda calculi. We start with Q, a quantum lambda calculus with classical control. We study its classical properties, such as confluence and Subject Reduction. We go on with an important quantum property of Q, called standardization, and successively, we study the expressive power of the proposed calculus, by proving the equivalence with the computational model of quantum circuit families. From the calculus Q, subsequently a sublanguage of Q called SQ is defined and studied: SQ is inspired to the Soft Linear Logic and it is a quantum lambda calculus intrinsically poly-time. Since Q and SQ have not an explicit measurement operator in the syntax, an implicit measurement at the end of the computations is assumed. Measurement problems are explicitly studied in a third quantum lambda calculus called Q*, an extension of Q with a measurement operator. Starting from the observation that an explicit measurement operator breaks the deterministic evolution of the computation by importing a probabilistic behavior, new technical instruments, such as the probabilistic computations and the mixed states are defined. We prove a confluence result for the calculus, also for the relevant case of infinite computations. In the last part of the thesis, we propose two labeled modal deduction systems able to describe quantum computations from a qualitative point of view. The two systems, called respectively MSQS and MSpQS, represent a starting point toward a new model to deal (in a qualitative way) with computational quantum structures, seen as Kripke models. 1
Rohling, Niklas [Verfasser]. "Quantum Computing with Spin and Valley Qubits in Quantum Dots / Niklas Rohling." Konstanz : Bibliothek der Universität Konstanz, 2015. http://d-nb.info/1095134507/34.
Full textPooley, Matthew Anthony. "Components for quantum computing based on optical transitions in single quantum dots." Thesis, University of Cambridge, 2013. https://www.repository.cam.ac.uk/handle/1810/245335.
Full textVranckx, Stéphane. "Dynamical study of diatomics : applications to astrochemistry, quantum control and quantum computing." Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209261.
Full text1) HeH+, a species of great astrochemical importance which is thought to be the first molecular species to have formed in the universe;
2) CO2+, a metastable dication of particular interest in quantum control experiments due to its long-lived lowest vibrational level;
3) 41K87Rb, a polar molecule that can be formed at very low temperature and trapped, making it a good candidate for quantum computing schemes.
First, we use ab initio methods to compute accurate potential energy curves for the lowest singlet and triplet states of HeH+ as well as the potential energy curves, transition dipole moments and nonadiabatic radial couplings of the ground 3Π state of CO2+ and of its 11 lowest 3Σ- states.
In a second step, we use this ab initio data to compute the photodissociation and radiative association cross sections for the a and b 3Σ+ states of HeH+, as well as the values of the corresponding rate constants for astrophysical environments. The photodissociation cross sections from the lowest vibrational level of CO2+ is also determined.
Going one step further, we optimize laser control fields that drive the photodissociation dynamics of HeH+ and CO2+ towards specific channels. We compare two field optimization methods: a Møller operator-based Local Control approach and Optimal Control Theory. In both cases, we add a constraint that minimizes the area of the optimized fields.
Finally, we focus on one of the potential applications of high-fidelity laser control: the use of small molecular systems as quantum computers. We more specifically study the potential implementation of both intra- and intermolecular logic gates on data encoded in hyperfine states of trapped ultracold polar 41K87Rb molecules, opening interesting perspectives in terms of extensibility.
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Dans cette thèse, nous étudions théoriquement les propriétés de molécules diatomiques, leur dynamique de réaction ainsi que le contrôle de cette dynamique à l'aide de champs laser. Notre travail porte plus spécifiquement sur trois espèces :
1) HeH+, un composé-clé en astrochimie considéré comme la première espèce moléculaire qui s'est formée dans l'univers ;
2) CO2+, un dication métastable qui se prête bien à des expériences de contrôle quantique en raison du relativement long temps de vie de son état vibrationnel le plus bas ;
3) 41K87Rb, une molécule polaire qui présente la particularité de pouvoir être formée à très basse température et piégée, ce qui en fait un bon support physique potentiel pour la réalisation d'un ordinateur quantique moléculaire.
Nous utilisons tout d'abord des méthodes de calcul ab initio afin d'obtenir les courbes d'énergie potentielle des premiers états singulets et triplets de HeH+ avec un haut de degré de précision, ainsi que les courbes d'énergie potentielle, les moments dipolaires de transition et les couplages non-adiabatiques radiaux de l'état fondamental 3Π de CO2+ et de ses 11 premiers états 3Σ-.
Ensuite, nous utilisons ces données ab initio pour calculer les sections efficaces de photodissociation et d'association radiative des états a et b 3Σ+ de HeH+, ainsi que les constantes cinétiques associées à ces processus dans les conditions rencontrées dans des environnements astrophysiques. Les sections efficaces de photodissociation du niveau vibrationnel le plus bas de CO2+ sont également calculées.
Nous allons ensuite un cran plus loin en optimisant des champs laser qui guident la dynamique de photodissociation de HeH+ et CO2+ vers des canaux de dissociation spécifiques. Nous comparons deux méthodes d'optimisation de ces champs: une approche de contrôle local basée sur les opérateurs de Møller et la théorie du contrôle optimal. Dans le deux cas, nous incluons une contrainte qui minimise l'aire des champs.
Enfin, nous nous concentrons sur l'une des applications possibles du contrôle laser à haute fidélité :l'utilisation de petits systèmes moléculaires comme ordinateurs quantiques. Nous étudions plus spécifiquement l'implémentation possible d'opérations logiques intra- et intermoléculaires sur des données encodées dans des états hyperfins de molécules de 41K87Rb piégées, ce qui ouvre des perspectives intéressantes en terme d'extensibilité.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Xu, Guanglei. "Adiabatic processes, noise, and stochastic algorithms for quantum computing and quantum simulation." Thesis, University of Strathclyde, 2018. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=30919.
Full textHnatenko, O. S. "Quantum computing. Quantum information technologies as the basis for future learning platforms." Thesis, ISMA University of Applied Science, Riga, Latvia, 2021. https://openarchive.nure.ua/handle/document/16270.
Full textWanzambi, Ellinor, and Stina Andersson. "Quantum Computing: Implementing Hitting Time for Coined Quantum Walks on Regular Graphs." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-444818.
Full textO'Hara, John. "Quantum light with quantum dots in III-V photonic integrated circuits : towards scalable quantum computing architectures." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/20113/.
Full textSauer, Jacob A. "Cold Atom Manipulation for Quantum Computing and Control." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4809.
Full textAlfares, Fawzan S. "Novel optimisation algorithms based on quantum computing principles." Thesis, Brunel University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415136.
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