Non-equilibrium Dynamics and Information Spreading in Many-body Quantum Systems

Non-equilibrium Dynamics and Information Spreading in Many-body Quantum Systems PDF Author: Dominik Hahn
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Languages : en
Pages : 0

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Non-equilibrium Dynamics and Information Spreading in Many-body Quantum Systems

Non-equilibrium Dynamics and Information Spreading in Many-body Quantum Systems PDF Author: Dominik Hahn
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Category :
Languages : en
Pages : 0

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Non-equilibrium Dynamics of Interacting Many-body Quantum Systems in One Dimension

Non-equilibrium Dynamics of Interacting Many-body Quantum Systems in One Dimension PDF Author: Bruno Bertini
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Languages : en
Pages :

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Nonequilibrium Many-Body Theory of Quantum Systems

Nonequilibrium Many-Body Theory of Quantum Systems PDF Author: Gianluca Stefanucci
Publisher: Cambridge University Press
ISBN: 1107354579
Category : Science
Languages : en
Pages : 619

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Book Description
The Green's function method is one of the most powerful and versatile formalisms in physics, and its nonequilibrium version has proved invaluable in many research fields. This book provides a unique, self-contained introduction to nonequilibrium many-body theory. Starting with basic quantum mechanics, the authors introduce the equilibrium and nonequilibrium Green's function formalisms within a unified framework called the contour formalism. The physical content of the contour Green's functions and the diagrammatic expansions are explained with a focus on the time-dependent aspect. Every result is derived step-by-step, critically discussed and then applied to different physical systems, ranging from molecules and nanostructures to metals and insulators. With an abundance of illustrative examples, this accessible book is ideal for graduate students and researchers who are interested in excited state properties of matter and nonequilibrium physics.

Probing Non-Equilibrium Dynamics in Two-Dimensional Quantum Gases

Probing Non-Equilibrium Dynamics in Two-Dimensional Quantum Gases PDF Author: Cheng-An Chen
Publisher: Springer Nature
ISBN: 3031133552
Category : Science
Languages : en
Pages : 151

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This thesis explores the physics of non-equilibrium quantum dynamics in homogeneous two-dimensional (2D) quantum gases. Ultracold quantum gases driven out of equilibrium have been prominent platforms for studying quantum many-body physics. However, probing non-equilibrium dynamics in conventionally trapped, inhomogeneous atomic quantum gases has been a challenging task because coexisting mass transport and spreading of quantum correlations often complicate experimental analyses. In this work, the author solves this technical hurdle by producing ultracold cesium atoms in a quasi-2D optical box potential. The exquisite optical trap allows one to remove density inhomogeneity in a degenerate quantum gas and control its dimensionality. The author also details the development of a high-resolution, in situ imaging technique to monitor the evolution of collective excitations and quantum transport down to atomic shot-noise, and at the length scale of elementary collective excitations. Meanwhile, tunable Feshbach resonances in ultracold cesium atoms permit precise and dynamical control of interactions with high temporal and even spatial resolutions. By employing these state-of-the-art techniques, the author performed interaction quenches to control the generation and evolution of quasiparticles in quantum gases, presenting the first direct measurement of quantum entanglement between interaction quench generated quasiparticle pairs in an atomic superfluid. Quenching to attractive interactions, this work shows stimulated emission of quasiparticles, leading to amplified density waves and fragmentation, forming 2D matter-wave Townes solitons that were previously considered impossible to form in equilibrium due to their instability. This thesis unveils a set of scale-invariant and universal quench dynamics and provides unprecedented tools to explore quantum entanglement transport in a homogenous quantum gas.

Dynamics of Quantum Information in Many-body Systems with Nonlocal Interactions

Dynamics of Quantum Information in Many-body Systems with Nonlocal Interactions PDF Author: Darvin Wanisch
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Category :
Languages : de
Pages : 0

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The dynamics of quantum information lies at the heart of future technologies that aim to utilize the laws of quantum mechanics for practical purposes. Beyond that, it provides a unifying language that shines new light on longstanding problems home to historically separate fields of theoretical physics. Considering how quantum information propagates and spreads over the degrees of freedom of a quantum many-body system far from equilibrium has proven particularly helpful for various subjects, ranging from the emergence of statistical mechanics in isolated quantum systems to the black hole information paradox. Crucial for these developments are impressive experimental advances that nowadays allow us to explore the nonequilibrium physics of paradigmatic, simple, and (almost) isolated quantum many-body systems in the laboratory. In this thesis, we investigate the dynamics of quantum information in one-dimensional systems of interacting qubits, i.e., spin-chains, where we particularly consider systems that embody nonlocal interactions. The latter are ubiquitous in many experimental platforms for quantum simulation. Our results reveal an interesting connection between two complementary probes of quantum information dynamics, i.e., entanglement growth and operator spreading. This connection allows us to characterize different dynamical classes and underlines that nonlocal interactions induce rich behavior, such as slow thermalization accompanied by superballistic information propagation. In particular, we show that the famous slowdown of entanglement growth in systems with powerlaw interactions implies a slowdown of operator dynamics. The latter clearly distinguishes a system with powerlaw interactions from a system possessing fast scrambling, a characteristic property of black holes and holographic duals to theories of quantum gravity.

Non-equilibrium Dynamics

Non-equilibrium Dynamics PDF Author: Peter D. Keefe
Publisher:
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Category :
Languages : en
Pages :

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NON-EQUILIBRIUM DYNAMICS OF MANY-BODY QUANTUM SYSTEMS

NON-EQUILIBRIUM DYNAMICS OF MANY-BODY QUANTUM SYSTEMS PDF Author:
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Category :
Languages : en
Pages :

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Rapid progress in nanotechnology and naofabrication techniques has ushered in a new era of quantum transport experiments. This has in turn heightened the interest in theoretical understanding of nonequilibrium dynamics of strongly correlated quantum systems. This project has advanced the frontiers of understanding in this area along several fronts. For example, we showed that under certain conditions, quantum impurities out of equilibrium can be reformulated in terms of an effective equilibrium theory; this makes it possible to use the gamut of tools available for quantum systems in equilibrium. On a different front, we demonstrated that the elastic power of a transmitted microwave photon in circuit QED systems can exhibit a many-body Kondo resonance. We also showed that under many circumstances, bipartite fluctuations of particle number provide an effective tool for studying many-body physics--particularly the entanglement properties of a many-body system. This implies that it should be possible to measure many-body entanglement in relatively simple and tractable quantum systems. In addition, we studied charge relaxation in quantum RC circuits with a large number of conducting channels, and elucidated its relation to Kondo models in various regimes. We also extended our earlier work on the dynamics of driven and dissipative quantum spin-boson impurity systems, deriving a new formalism that makes it possible to compute the full spin density matrix and spin-spin correlation functions beyond the weak coupling limit. Finally, we provided a comprehensive analysis of the nonequilibrium transport near a quantum phase transition in the case of a spinless dissipative resonant-level model. This project supported the research of two Ph. D. students and two postdoctoral researchers, whose training will allow them to further advance the field in coming years.

Non-equilibrium Quantum Physics, Many Body Systems, and Foundations of Quantum Mechanics

Non-equilibrium Quantum Physics, Many Body Systems, and Foundations of Quantum Mechanics PDF Author: Peter D. Keefe
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Non-equilibrium Dynamics of Tunnel-Coupled Superfluids

Non-equilibrium Dynamics of Tunnel-Coupled Superfluids PDF Author: Marine Pigneur
Publisher: Springer Nature
ISBN: 3030528448
Category : Science
Languages : en
Pages : 204

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Book Description
The relaxation of isolated quantum many-body systems is a major unsolved problem of modern physics, which is connected to many fundamental questions. However, realizations of quantum many-body systems which are both well isolated from their environment and accessible to experimental study are scarce. In recent years, the field has experienced rapid progress, partly attributed to ultra-cold atoms. This book presents the experimental study of a relaxation phenomenon occurring in a one-dimensional bosonic Josephson junction. The system consists of two 1D quasi Bose-Einstein condensates of 87Rb, magnetically trapped on an atom chip. Using radio-frequency dressing, the author deforms a single harmonic trap, in which the atoms are initially condensed, into a double-well potential and realizes a splitting of the wave function. A large spatial separation and a tilt of the double-well enable the preparation of a broad variety of initial states by precisely adjusting the initial population and relative phase of the two wave packets, while preserving the phase coherence. By re-coupling the two wave packets, the author investigates tunneling regimes such as Josephson (plasma) oscillations and macroscopic quantum self-trapping. In both regimes, the tunneling dynamics exhibits a relaxation to a phase-locked equilibrium state contradicting theoretical predictions. The experimental results are supported with an empirical model that allows quantitative discussions according to various experimental parameters. These results illustrate how strongly the non-equilibrium dynamics differ from the equilibrium one, which is well described by thermodynamics and statistical physics.

Nonequilibrium Phenomena in Many-body Quantum Systems

Nonequilibrium Phenomena in Many-body Quantum Systems PDF Author: Markus Philip Ludwig Heyl
Publisher:
ISBN:
Category :
Languages : en
Pages : 164

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