scholarly journals Entanglement spreading and quasiparticle picture beyond the pair structure

2020 ◽  
Vol 8 (3) ◽  
Author(s):  
Alvise Bastianello ◽  
Mario Collura
Keyword(s):  
Quantum Systems ◽  
One Dimension ◽  
Many Body ◽  
Initial State ◽  
Perfect Agreement ◽  
Quasi Particle ◽  
Simple Assumption ◽  
The Common ◽  
Quasiparticle Picture ◽  
Number Of Particles

The quasi-particle picture is a powerful tool to understand the entanglement spreading in many-body quantum systems after a quench. As an input, the structure of the excitations' pattern of the initial state must be provided, the common choice being pairwise-created excitations. However, several cases exile this simple assumption. In this work we investigate weakly-interacting to free quenches in one dimension. This results in a far richer excitations' pattern where multiplets with a larger number of particles are excited. We generalize the quasi-particle ansatz to such a wide class of initial states, providing a small-coupling expansion of the Rényi entropies. Our results are in perfect agreement with iTEBD numerical simulations.

scholarly journals Probing the edge between integrability and quantum chaos in interacting few-atom systems

Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 486
Author(s):  
Thomás Fogarty ◽  
Miguel Ángel García-March ◽  
Lea F. Santos ◽  
Nathan L. Harshman
Keyword(s):  
Quantum Chaos ◽  
Cold Atoms ◽  
Quantum Systems ◽  
Particle Interactions ◽  
Body System ◽  
Many Body ◽  
One Dimensional ◽  
The Core ◽  
Emergence Of Chaos ◽  
Number Of Particles

Interacting quantum systems in the chaotic domain are at the core of various ongoing studies of many-body physics, ranging from the scrambling of quantum information to the onset of thermalization. We propose a minimum model for chaos that can be experimentally realized with cold atoms trapped in one-dimensional multi-well potentials. We explore the emergence of chaos as the number of particles is increased, starting with as few as two, and as the number of wells is increased, ranging from a double well to a multi-well Kronig-Penney-like system. In this way, we illuminate the narrow boundary between integrability and chaos in a highly tunable few-body system. We show that the competition between the particle interactions and the periodic structure of the confining potential reveals subtle indications of quantum chaos for 3 particles, while for 4 particles stronger signatures are seen. The analysis is performed for bosonic particles and could also be extended to distinguishable fermions.

scholarly journals Hubbard-Stratonovich-like Transformations for Few-Body Interactions

2018 ◽  
Vol 175 ◽  
pp. 11012
Author(s):  
Christopher Körber ◽  
Evan Berkowitz ◽  
Thomas Luu
Keyword(s):  
Perturbation Theory ◽  
Great Accuracy ◽  
Quantum Systems ◽  
Collective Phenomena ◽  
Many Body ◽  
Chiral Perturbation ◽  
Body Level ◽  
The Many ◽  
Three Body ◽  
Number Of Particles

Through the development of many-body methodology and algorithms, it has become possible to describe quantum systems composed of a large number of particles with great accuracy. Essential to all these methods is the application of auxiliary fields via the Hubbard-Stratonovich transformation. This transformation effectively reduces two-body interactions to interactions of one particle with the auxiliary field, thereby improving the computational scaling of the respective algorithms. The relevance of collective phenomena and interactions grows with the number of particles. For many theories, e.g. Chiral Perturbation Theory, the inclusion of three-body forces has become essential in order to further increase the accuracy on the many-body level. In this proceeding, the an-alytical framework for establishing a Hubbard-Stratonovich-like transformation, which allows for the systematic and controlled inclusion of contact three-and more-body inter-actions, is presented.

scholarly journals Predicting Imperfect Echo Dynamics in Many-Body Quantum Systems

2020 ◽  
Vol 75 (5) ◽  
pp. 403-411 ◽  
Author(s):  
Lennart Dabelow ◽  
Peter Reimann
Keyword(s):  
Nonequilibrium State ◽  
Quantum Systems ◽  
Many Body ◽  
Echo Signal ◽  
Initial State ◽  
Time Period ◽  
Nonequilibrium States ◽  
The Many ◽  
Backward Propagation ◽  
Analytic Prediction

AbstractEcho protocols provide a means to investigate the arrow of time in macroscopic processes. Starting from a nonequilibrium state, the many-body quantum system under study is evolved for a certain period of time τ. Thereafter, an (effective) time reversal is performed that would – if implemented perfectly – take the system back to the initial state after another time period τ. Typical examples are nuclear magnetic resonance imaging and polarisation echo experiments. The presence of small, uncontrolled inaccuracies during the backward propagation results in deviations of the “echo signal” from the original evolution and can be exploited to quantify the instability of nonequilibrium states and the irreversibility of the dynamics. We derive an analytic prediction for the typical dependence of this echo signal for macroscopic observables on the magnitude of the inaccuracies and on the duration τ of the process, and verify it in numerical examples.

scholarly journals Quarkonia dynamics in the QGP with open quantum systems

2022 ◽  
Vol 258 ◽  
pp. 05009
Author(s):  
Stéphane Delorme ◽  
Thierry Gousset ◽  
Roland Katz ◽  
Pol-Bernard Gossiaux
Keyword(s):  
Real Time ◽  
Quark Gluon Plasma ◽  
Open Quantum Systems ◽  
Gluon Plasma ◽  
Quantum Systems ◽  
Master Equations ◽  
Temperature Evolution ◽  
One Dimension ◽  
Initial State ◽  
Time Dynamics

We investigate the real-time dynamics of a correlated heavy quarkantiquark pair inside the Quark-Gluon Plasma using new quantum master equations derived from first QCD principles and based on the work of Blaizot & Escobedo [4]. The full equations are directly numerically solved in one-dimension to reduce computing costs and is used to gain insight on the dynamics in both a static and evolving medium following a Björken-like temperature evolution. The effect of the initial state on the dynamics is also studied.

scholarly journals Many-body localization: stability and instability

2017 ◽  
Vol 375 (2108) ◽  
pp. 20160422 ◽  
Author(s):  
Wojciech De Roeck ◽  
John Z. Imbrie
Keyword(s):  
Higher Dimensions ◽  
Quantum Systems ◽  
One Dimension ◽  
Reasonable Assumption ◽  
Level Spacing ◽  
Weak Disorder ◽  
Many Body ◽  
Integrals Of Motion ◽  
Stability And Instability ◽  
Rare Regions

Rare regions with weak disorder (Griffiths regions) have the potential to spoil localization. We describe a non-perturbative construction of local integrals of motion (LIOMs) for a weakly interacting spin chain in one dimension, under a physically reasonable assumption on the statistics of eigenvalues. We discuss ideas about the situation in higher dimensions, where one can no longer ensure that interactions involving the Griffiths regions are much smaller than the typical energy-level spacing for such regions. We argue that ergodicity is restored in dimension d >1, although equilibration should be extremely slow, similar to the dynamics of glasses. This article is part of the themed issue ‘Breakdown of ergodicity in quantum systems: from solids to synthetic matter’.

scholarly journals Randomness of Eigenstates of Many-Body Quantum Systems

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 227 ◽  
Author(s):  
Li-Zhen Sun ◽  
Qingmiao Nie ◽  
Haibin Li
Keyword(s):  
Hard Core ◽  
Underlying Mechanism ◽  
Quantum Systems ◽  
One Dimension ◽  
Many Body ◽  
Random Vectors ◽  
Boson System ◽  
Many Body Systems

The emergence of random eigenstates of quantum many-body systems in integrable-chaos transitions is the underlying mechanism of thermalization for these quantum systems. We use fidelity and modulus fidelity to measure the randomness of eigenstates in quantum many-body systems. Analytic results of modulus fidelity between random vectors are obtained to be a judge for the degree of randomness. Unlike fidelity, which just refers to a kind of criterion of necessity, modulus fidelity can measure the degree of randomness in eigenstates of a one-dimension (1D) hard-core boson system and identifies the integrable-chaos transition in this system.

scholarly journals Generalized-hydrodynamic approach to inhomogeneous quenches: correlations, entanglement and quantum effects

2021 ◽  
Vol 2021 (11) ◽  
pp. 114004
Author(s):  
Vincenzo Alba ◽  
Bruno Bertini ◽  
Maurizio Fagotti ◽  
Lorenzo Piroli ◽  
Paola Ruggiero
Keyword(s):  
Quantum Systems ◽  
Translational Symmetry ◽  
Many Body ◽  
Initial State ◽  
Future Directions ◽  
Entanglement Evolution ◽  
Hydrodynamic Approach ◽  
Open Questions ◽  
Dependent Correlation ◽  
Generic Time

Abstract We give a pedagogical introduction to the generalized hydrodynamic approach to inhomogeneous quenches in integrable many-body quantum systems. We review recent applications of the theory, focusing in particular on two classes of problems: bipartitioning protocols and trap quenches, which represent two prototypical examples of broken translational symmetry in either the system initial state or post-quench Hamiltonian. We report on exact results that have been obtained for generic time-dependent correlation functions and entanglement evolution, and discuss in detail the range of applicability of the theory. Finally, we present some open questions and suggest perspectives on possible future directions.

scholarly journals Dynamical manifestations of quantum chaos: correlation hole and bulge

2017 ◽  
Vol 375 (2108) ◽  
pp. 20160434 ◽  
Author(s):  
E. J. Torres-Herrera ◽  
Lea F. Santos
Keyword(s):  
Quantum Chaos ◽  
Entanglement Entropy ◽  
Quantum Systems ◽  
Direct Access ◽  
Many Body ◽  
Initial State ◽  
Von Neumann ◽  
Interacting Systems ◽  
Correlation Hole ◽  
The Many

A main feature of a chaotic quantum system is a rigid spectrum where the levels do not cross. We discuss how the presence of level repulsion in lattice many-body quantum systems can be detected from the analysis of their time evolution instead of their energy spectra. This approach is advantageous to experiments that deal with dynamics, but have limited or no direct access to spectroscopy. Dynamical manifestations of avoided crossings occur at long times. They correspond to a drop, referred to as correlation hole, below the asymptotic value of the survival probability and to a bulge above the saturation point of the von Neumann entanglement entropy and the Shannon information entropy. By contrast, the evolution of these quantities at shorter times reflects the level of delocalization of the initial state, but not necessarily a rigid spectrum. The correlation hole is a general indicator of the integrable–chaos transition in disordered and clean models and as such can be used to detect the transition to the many-body localized phase in disordered interacting systems. This article is part of the themed issue ‘Breakdown of ergodicity in quantum systems: from solids to synthetic matter’.

scholarly journals Multiparticle quantum plasmonics

Nanophotonics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1243-1269 ◽  
Author(s):  
Chenglong You ◽  
Apurv Chaitanya Nellikka ◽  
Israel De Leon ◽  
Omar S. Magaña-Loaiza
Keyword(s):  
Quantum Dynamics ◽  
Degrees Of Freedom ◽  
Single Photon ◽  
Quantum Systems ◽  
Many Body ◽  
Statistical Fluctuations ◽  
Quantum Plasmonics ◽  
Control Of Quantum Systems ◽  
Multiparticle Systems ◽  
Quantum Photonics

AbstractA single photon can be coupled to collective charge oscillations at the interfaces between metals and dielectrics forming a single surface plasmon. The electromagnetic near-fields induced by single surface plasmons offer new degrees of freedom to perform an exquisite control of complex quantum dynamics. Remarkably, the control of quantum systems represents one of the most significant challenges in the field of quantum photonics. Recently, there has been an enormous interest in using plasmonic systems to control multiphoton dynamics in complex photonic circuits. In this review, we discuss recent advances that unveil novel routes to control multiparticle quantum systems composed of multiple photons and plasmons. We describe important properties that characterize optical multiparticle systems such as their statistical quantum fluctuations and correlations. In this regard, we discuss the role that photon-plasmon interactions play in the manipulation of these fundamental properties for multiparticle systems. We also review recent works that show novel platforms to manipulate many-body light-matter interactions. In this spirit, the foundations that will allow nonexperts to understand new perspectives in multiparticle quantum plasmonics are described. First, we discuss the quantum statistical fluctuations of the electromagnetic field as well as the fundamentals of plasmonics and its quantum properties. This discussion is followed by a brief treatment of the dynamics that characterize complex multiparticle interactions. We apply these ideas to describe quantum interactions in photonic-plasmonic multiparticle quantum systems. We summarize the state-of-the-art in quantum devices that rely on plasmonic interactions. The review is concluded with our perspective on the future applications and challenges in this burgeoning field.

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