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 89 for “"dephasing"”.
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Decoherence and Dephasing of Vibronic Excitons /
… to be used. In this thesis, the significance of dephasing and decoherence of vibronic excitons in molecular systems is investigated and the signatures of electronic-vibrational interaction in the two-dimensional electronic spectra are analyzed with the focus on evolution of molecular excitation …
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Coherence, Dephasing, and Quantum Interference in Colloidal Perovskite Nanocrystals
As the development of photonic quantum technologies continues to be pushed forward, the need for a source of quantum light, the so-called quantum emitter, has been ever-growing. The requirements for a quantum emitter are onerous: indistinguishable photon or entangled photon pairs need to be …
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Low -Frequency 1/F Noise: Low Temperature Measurements and Effect on Superconducting Qubit Dephasing
… can lead to substantial, measurement-induced dephasing in superconducting qubits. The purpose of this work is to measure this noise as a function of temperature and to simulate its effect on the measurement dynamics associated with superconducting qubits. In Nb trilayer junctions we measure …
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Low-frequency 1/f noise : low temperature measurements and effect on superconducting qubit dephasing
… can lead to substantial, measurement-induced dephasing in superconducting qubits. The purpose of this work is to measure this noise as a function of temperature and to simulate its effect on the measurement dynamics associated with superconducting qubits. In Nb trilayer junctions we measure …
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Temperature and High Pressure Light Scattering Studies of Linear Triatomic Molecules in the Liquid State (Reorientation, Dephasing, Collision-Induced)
Light scattering lineshape analysis provides a powerful experimental probe of molecular dynamics in the liquid phase. This thesis consists of temperature and high pressure studies of collision-induced scattering in carbon disulfide and carbonyl sulfide, and reorientational motion and vibrational …
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Decoherence, Master Equation for Open Quantum Systems, and the Subordination Theory
… the environment produce also decoherence, named dephasing. Decoherence is interpreted as the entanglement of the coherent superposition of these two states with the environment. The joint action of inphasing and dephasing generates a Markov master equation statistically equivalent to a random …
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High Fidelity Universal Gates Performed on a Continuously-Decoupled Coherence Enhanced Transmon Qubit
… qubits and qubit networks; most chiefly, pure dephasing which limits the operational time any gate-sequence can produce a high-fidelity result. In this dissertation, I present the results of my experiment, performing fast, high fidelity, universal single-qubit gates, on a qubit which has been …
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Optimizing coherence and anharmonicity of superconducting qubit
… T1 for depolarization processes and T2 for dephasing. This thesis reviews and investigates the decoherence properties of superconducting qubits. The main goal of the thesis is to analyze the tradeoff between anharmonicity and dephasing in a qubit unimon. Recently developed unimon …
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Revisiting physics of quantum bits
… dissipative effects and the trivial resultant dephasing, can also cause pure dephasing. Furthermore, it is demonstrated that, in the current domain of interest for quantum computation purposes, the effective Hamiltonian of single molecule magnets in interaction with a spin bath differs from the …
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Exciton Dynamics and Optical Properties of Lead Halide Perovskite Nanocrystals: From Nanorods to Nanocubes
… problems with stability. Additionally, dephasing mechanisms and coupling to phonons are not yet well understood in these semiconductors. In the first part of the thesis, I investigate highly confined, anisotropic CsPbBr3 nanorods, elucidating the photophysics governing their broad …
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Towards qubit noise spectroscopy by quantum bang-bang control
… a simple random rotation model of single qubit dephasing, I demonstrate how quantum bang-bang control can distinguish between dephasing under different stochastic processes. I also show how quantum bang-bang control can determine noise coupling in a toy model where noise couples to the qubit via …
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Coherent two photon excitation within an extended cloud of Rubidium 85 for the purposes of atomic interferometry and cooling
… of non-radiative and partially non-stochastic dephasing mechanisms. Due to a high level of decoherence during the spin-echo experiments further investigation is required to determine the exact ratio of stochastic to non-stochastic dephasing.
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Quantum phenomena in disordered conductors
… that decays exponentially with the electron dephasing length. This model is shown to be in quantitative agreement with the experimental data on the organic conductor TTT2I3_8· We also show how the low-temperature positive magnetoresistance observed in TTT2 I3_ 8 and other quasi-lD conductors …
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Spin Dynamics in a Tunable Heisenberg Magnet Realized with Ultracold Atoms
… from ballistic to diffusive transport. Spin dephasing: A transverse spin-helix pattern is sensitive to additional decay mechanisms: Anisotropic spin couplings break spin-rotational symmetry. Transverse spin components are no longer conserved and can decay not only by transport, but also by …
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Non-Gaussian noise spectroscopy with superconducting qubits
… the higher-order spectrum of a non-Gaussian dephasing process using a superconducting qubit as a noise spectrometer. This experimental demonstration of non-Gaussian noise spectroscopy protocol represents a major step towards the goal of demonstrating a complete noise spectral characterization …
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Ultrafast Raman Scattering in Plasmonic Nanocavities
… of the vibrational population and vibrational dephasing for each nanocavity. The vibrational dephasing is found to strongly accelerate depending on the exciting laser intensity. Understanding these modified vibrational dynamics on plasmonically-active substrates is crucial for improving …
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The tin-vacancy centre in diamond: a coherent spin-photon interface for quantum network nodes
… The crystal strain suppresses phonon-induced dephasing processes, enabling coherence times of up to 223(10) μs at 4 K, a record-value for group IV colour centres. For a low-strain tin-vacancy centre in a diamond nanopillar device, we show polarisation of more than 65 % of a strongly coupled …
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Experimental demonstration of high-fidelity entanglement via Rydberg blockade
… achieved, T ≈ 10 μK, the ground-Rydberg dephasing times measured through Ramsey spectroscopy find coherence times around twice that of previously reported experiments, over an order of magnitude greater than the gate time.;Demonstration of Rydberg blockade between two atoms with a …
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Understanding and measuring flow in aortic stenosis with MRI
… determined that signal loss, due to intravoxel dephasing, decreased the reliability of the measured forward ow jet velocities. Extreme signal loss in the jet eventuated in salt and pepper noise, which, with a mean velocity of zero, resulted in the underestimation. Intravoxel dephasing signal …
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Femtosecond laser studies of molecular wavepacket dynamics in the cesium dimer
… 20 psec, and their decay is attributed to the dephasing of the vibrational wavefunctions that comprise the wavepacket.
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