Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 29 for “"Open Quantum System"”.
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Open quantum system theory from an information perspective
Theoretical investigations of open quantum systems have uncovered a wide variety of unique dynamical phenomena. For instance, current research in quantum information technology aims to control and utilize time-delayed system-reservoir interactions and phonon-induced dynamical dissipative processes …
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Open quantum system dynamics for describing state transfer
<p>In principle a quantum system could be used to simulate another quantum system. The purpose of such a simulation would be to obtain information about problems which are difficult to simulate on a classical computer due to the exponential increase of the Hilbert space with the size of the system, …
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Scalable approaches to the characterization of open quantum system dynamics
… challenges in the physical realization of quantum information processing (QIP) is the precise control of the system. In order to achieve this, we characterize the gates, errors, and noise occurring in experimental setups. In this thesis we develop and further study characterization methods, …
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Optimal control in an open quantum system : selecting DNP pathways in an electron-nuclear system
There is much interest in improving quantum control techniques for the purposes of quantum information processing. High fidelity control is necessary for the future of quantum computing. Optimal control theory has been used successfully to numerically optimize control sequences for spin-based …
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A study on complexity
This thesis explores quantum complexity for various quantum systems. Quantum complexity is a well defined quantity in quantum information theory that measures the difficulty of constructing a quantum state from a given reference state and so far, various methods within high energy physics …
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Numerical Case Study of an Atom-Photon Interaction in a Cavity Exploring Quantum Control
… cavity mode (Jaynes-Cumming model) in a closed quantum system in resonance or near resonance for a time-dependent coupling coefficient g(t) in both the interaction and rotating picture by implementing a novel numerical method called MG4 and compare out results to the Runge-Kutta 4th (RK4) order …
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G-CONSISTENT SUBSETS AND REDUCED DYNAMICAL QUANTUM MAPS
A quantum system which evolves in time while interacting with an external environ- ment is said to be an open quantum system (OQS), and the influence of the environment on the unperturbed unitary evolution of the system generally leads to non-unitary dynamics. This kind of open system dynamical …
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Quantum information and thermodynamics of general relativity
We treat an Unruh-DeWitt detector as an open quantum system, with a quantum field playing the role of the environment, and evaluate the response of a uniformly accelerated detector for different types of interaction between the detector and the field. We derive the evolution equations for the …
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Generation and application of squeezed light
… squeezed light and its effects in two different quantum optical systems is presented. Firstly a more technology-oriented application of squeezed states is discussed, namely a four-wave mixing optical rotation sensor. In an optical rotation sensor or “laser gyroscope” an external rotation is …
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Tensor network states simulations of exciton-phonon quantum dynamics for applications in artifcial light-harvesting
… models of noise assisted transport at the quantum level is challenging due to the intractable size of the environmental wave function. I developed a powerful tree tensor network states (TTNS) method that finds an optimally compressed explicit representation of the combined electronic and …
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Sterile neutrinos in cold climates
… discussion of neutrino coherence properties. The open-quantum-system picture of neutrino beams, which allows a rigorous prediction of coherence distances for accelerator neutrinos, is presented. Validity of the standard treatment of active and sterile neutrino oscillations at short baselines is …
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Noncommutative Sobolev type inequalities
… Sobolev type inequalities in the noncommutative (quantum) settings. We establish the abstract Bakry-\'Emery criterion for the operator-valued $f$-Sobolev inequalities on the derivation triple. We recapture the celebrated Bakry-\'Emery theorem for operator-valued functions on Riemannian manifolds. …
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Mixed-state topology and response
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-12-01
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Non-Markovian Dynamics of Open Quantum Systems
An open quantum system is a quantum system that interacts with some environment whose degrees of freedom have been coarse grained away. This model describes non-equilibrium processes more general than scattering-matrix formulations. Furthermore, the microscopically-derived environment provides a …
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Dynamical approach in quantum information theory
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-08-01
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Operator algebra perspectives on interacting quantum systems
… mathematical physics is to study interacting systems beyond the reach of perturbation theory. This thesis studies interacting quantum systems using the mathematical theory of operator algebras. In the first part of this thesis, we consider how to construct quantum many-body systems from …
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The multi Davydov-Ansatz
… functions, to illuminate several aspects of open quantum system dynamics and quantum many-body theory. By two artifices alongside the time-dependent variational principle we extract from this Ansatz, commonly considered ill-behaved and not converging, a highly stable and converging method. …
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Charge and excitation-energy transfer in time-dependent density functional theory
… for standard TDDFT ranging from chain-like systems over excitonic excitations in semiconductor nanoclusters to short- and long-range charge-transfer excitations. At the same time, it does not spoil the reasonable accuracy that already (semi)local functionals exhibit for local excitations. …
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Aspects of Quantum Coherence
… our aim is to study several aspects related to quantum coherence as understood to correspond with the non-classical behaviour that can be observed for certain particular states of a physical system. In particular we are interested in the possible mechanisms that result in dynamically induced …
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Robustness of Fixed Points of Quantum Processes
… of fixed points (or invariant states) of quantum processes. In the first part of the thesis, we address the following question: Given a quantum channel and a quantum state which is almost a fixed point of the channel, can we find a new channel and a new state, which are respectively close …
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