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Showing 1 to 13 of 13 for “"path integral methods"”.
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Path integral methods for quantum dynamics in condensed phases
… 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 …
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Path integral methods for the large-N Kondo model
A path integral formulation of the SU(N) Kondo model is explored as a possible theoretical tool for studying generalizations of the model, such as the Kondo lattice, which are difficult to study by other means. Saddle point approximations to the path integral lead to an expansion in powers of 1/N. …
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Exciton-vibration dynamics using real-time path integral methods
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-12-04 without embargo terms
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Path integral methods for accurate simulation of condensed phase reactions
The student, Peter Walters, submitted this Dissertation for approval on 2016-04-19 at 16:01.
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Quantum-classical and semiclassical path integral methods for condensed phase dynamics
… system is often described by the density matrix. Path integral formulation of the density matrix provides a versatile tool for studying quantum dynamics in condensed phase. Unlike the Schro ̈dinger equation in which the wavefunction is central, Feynman’s path integral formulation is trajectory …
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On defect CFT and path integral methods for entanglement in quantum field theories
… chapters of the thesis, we will study defect CFT methods based on the replica trick for characterizing quantum information in quantum field theories. We calculate a coefficient that characterizes the strength of the two point function of the displacement operator in the replica twist defect placed …
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Path-integral studies of quantum statistical effects in vibrational spectroscopy
… components of the imaginary-time Feynman paths that are responsible for quantum coherence. Using a simple model of perturbed harmonic oscillators, it is shown that most of the intensity differences between quantum and classical non-fundamental (overtone, combination, and difference) bands …
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Approximations to Matsubara Dynamics for Vibrational Spectra
In this thesis, we investigate path-integral methods for the purpose of accurately and efficiently including nuclear quantum effects in vibrational spectra, with a particular focus on anharmonic dynamics and non-fundamental transitions. All the methods investigated are approximations to Matsubara …
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Bosonization in 1 + 1/2 dimensions
… conditions for Luttinger fermions. We use path-integral methods to calculate the bosonized fermionic currents on the half-line and derive their commutation relations for a system with a boundary. We compute the fermion determinant of the fermionic fluctuations for a system with a boundary …
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On the exact renormalization of states in quantum field theories
… quantum features of field theories. By using path integral methods, we can port our understanding of the renormalization of Euclidean field theories to states of the QFT Hilbert space. Such constructions require the use of manifolds with boundary in the path integral, presenting technical and …
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Quasicentroid Molecular Dynamics
… subject to thermally averaged Feynman path fluctuations (“the mean field”). This theory approximates the dynamics of systems at thermal equilibrium that follow quantum Boltzmann statistics and undergo rapid quantum decoherence. As it relies on purely classical mechanics, the theory …
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Quantum dynamics in the condensed phase: path integrals, master equations and purity
… here builds up on existing highly accurate methods developed in our group, namely the quasi-adiabatic propagator (QuAPI) and the quantum-classical path integral (QCPI). In particular, we present the incorporation of Langevin friction by eliminating classical trajectories, and a …
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Two-state systems with non-Markovian thermal and squeezed quantum noise inputs
… is amenable to solution by ordinary stochastic methods, of which numerical simulation plays the most significant role in our calculations. The dissipative double-well system is relevant to the search for macroscopic quantum coherence in superconducting quantum interference devices, and previous …