Probing Slow Relaxation and Many-Body Localization in Two-Dimensional Quasiperiodic Systems

Bordia, Pranjal; Lüschen, Henrik P.; Scherg, Sebastian; Gopalakrishnan, Sarang; Knap, Michael; Schneider, Ulrich; Bloch, Immanuel

doi:10.1103/physrevx.7.041047

Cited by 286 publications

(318 citation statements)

References 58 publications

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“…While this offers unique perspectives for studying paradigmatic models in condensed matter physics, the scope of cold atom research has extended well beyond such initial ideas. Exciting new research directions include the dynamical emergence of thermal equilibrium in isolated quantum systems [1], and the observation of many-body localization [3], linked to the breakdown of ergodicity [4,5]. Another example is the polaron quasiparticle, which was originally introduced by Landau [6] to describe the interaction of electrons with the atomic crystal of a solid, and has since been employed to understand a broad range of problems in condensed matter physics [7].…”

Section: Introductionmentioning

confidence: 99%

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Critical slowdown of non-equilibrium polaron dynamics

et al. 2019

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We study the quantum dynamics of a single impurity following its sudden immersion into a Bose-Einstein condensate. The ensuing formation of the Bose polaron in this general setting can be seen as impurity decoherence driven by the condensate, which we describe within a master equation approach. We derive rigorous analytical results for this decoherence dynamics, and thereby reveal distinct stages of its evolution from a universal stretched exponential initial relaxation to the final approach to equilibrium. The associated polaron formation time exhibits a strong dependence on the impurity speed and is found to undergo a critical slowdown around the speed of sound of the condensate. This rich non-equilibrium behavior of quantum impurities is of direct relevance to recent cold atom experiments, in which Bose polarons are created by a sudden quench of the impurity-bath interaction.

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Section: Introductionmentioning

confidence: 99%

“…Repeating this procedure successively gives a systematic asymptotic expansion in powers oft 1 . It turns out that we have to go to order t 1 3 to get a non-zero contribution In the second equality we use that at lowk the functions asymptotically behave like q n  -…”

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confidence: 99%

Critical slowdown of non-equilibrium polaron dynamics

et al. 2019

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“…This has led to the discovery of novel topological or symmetry-broken phases [4,[7][8][9][10][11], which cannot exist in thermalizing systems, with the particularly prominent example of time crystals breaking not only spatial but also temporal symmetries [12][13][14][15][16]. Although many signatures of MBL have been accessed experimentally [17][18][19][20][21][22][23][24], dissipation induced by a remaining coupling to an environment, even if weak, has turned out to have a crucial impact onto the long-time dynamics [24][25][26][27][28][29][30][31][32][33]. Specifically, external baths with large bandwidths and delocalized excitations are expected to force MBL systems towards thermalization, which destabilizes the nonergodic properties central for the anticipated new phase structures.…”

Section: Introductionmentioning

confidence: 99%

Describing many-body localized systems in thermal environments

Schnell

Tomasi

et al. 2019

New J. Phys.

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In this work we formulate an efficient method for the description of fully many-body localized systems in weak contact with thermal environments at temperature T. The key idea is to exploit the representation of the system in terms of quasi-local integrals of motion (l-bits) to efficiently derive the generator for the quantum master equation in Born-Markov approximation. We, moreover, show how to compute the steady state of this equation efficiently by using quantum-jump Monte-Carlo techniques as well as by deriving approximate kinetic equations of motion. As an example, we consider a one-dimensional disordered extended Hubbard model for spinless fermions, for which we derive the l-bit representation approximately by employing a recently proposed method valid in the limit of strong disorder and weak interactions. Coupling the system to a global thermal bath, we study the transport between two leads with different chemical potentials at both of its ends. We find that the temperature-dependent current is captured by an interaction-dependent version of Mott's law for variable range hopping, where transport is enhanced/lowered depending on whether the interactions are attractive or repulsive, respectively. We interpret these results in terms of spatio-energetic correlations between the l-bits.

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“…Experimental quantum systems that fail to thermalize thus command a great deal of interest. A small number of highly engineered examples focussed on the dynamics of ultracold atoms have confirmed the principle of MBL [19][20][21][22][23][24][25][26][27]. These results invite an intriguing question: in systems with stronger interactions and stronger disorder, could a state of many-body localization (MBL) arise naturally?…”

Section: Introductionmentioning

confidence: 99%

Many-body physics with ultracold plasmas: quenched randomness and localization

Sous

Grant

2019

New J. Phys.

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The exploration of large-scale many-body phenomena in quantum materials has produced many important experimental discoveries, including novel states of entanglement, topology and quantum order as found for example in quantum spin ices, topological insulators and semimetals, complex magnets, and high-T c superconductors. Yet, the sheer scale of solid-state systems and the difficulty of exercising exacting control of their quantum mechanical degrees of freedom limit the pace of rational progress in advancing the properties of these and other materials. With extraordinary effort to counteract natural processes of dissipation, precisely engineered ultracold quantum simulators could point the way to exotic new materials. Here, we look instead to the quantum mechanical character of the arrested state formed by a quenched ultracold molecular plasma. This novel class of system arises spontaneously, without a deliberate engineering of interactions, and evolves naturally from statespecified initial conditions, to a long-lived final state of canonical density, in a process that conflicts with classical notions of plasma dissipation and neutral dissociation. We take information from experimental observations to develop a conceptual argument that attempts to explain this state of arrested relaxation in terms of a minimal phenomenological model of randomly interacting dipoles of random energies. This model of the plasma forms a starting point to describe its observed absence of relaxation in terms of many-body localization (MBL). The large number of accessible Rydberg and excitonic states gives rise to an unconventional web of many-body interactions that vastly exceeds the complexity of MBL in a conventional few-level scheme. This experimental platform thus opens an avenue for the coupling of dipoles in disordered environments that will demand the development of new theoretical tools.

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Probing Slow Relaxation and Many-Body Localization in Two-Dimensional Quasiperiodic Systems

Cited by 286 publications

References 58 publications

Critical slowdown of non-equilibrium polaron dynamics

Critical slowdown of non-equilibrium polaron dynamics

Describing many-body localized systems in thermal environments

Many-body physics with ultracold plasmas: quenched randomness and localization

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