Glassy dynamics due to a trajectory phase transition in dissipative Rydberg gases

Abstract

The physics of highly excited Rydberg atoms is governed by blockade or exclusion interactions that hinder the excitation of atoms in the proximity of a previously excited one. This leads to cooperative effects and a relaxation dynamics displaying space-time heterogeneity similar to what is observed in the relaxation of glass-forming systems. Here we establish theoretically the existence of a glassy dynamical regime in an open Rydberg gas, associated with phase coexistence at a first-order transition in dynamical large deviation functions. This transition occurs between an active phase of low density in which dynamical processes take place on short timescales, and an inactive phase in which excited atoms are dense and the dynamics is highly arrested. We perform a numerically exact study and develop a mean-field approach that allows us to understand the mechanics of this phase transition. We show that radiative decay -which becomes experimentally relevant for long times -moves the system away from dynamical phase coexistence. Nevertheless, the dynamical phase transition persists and causes strong fluctuations in the observed dynamics. arXiv:1804.03070v2 [cond-mat.stat-mech]

Physical swap dynamics, shortcuts to relaxation, and entropy production in dissipative Rydberg gases

“…This effect is attenuated when the dynamical arrest is reduced, as in the curve for R = 1.5, which is only moderately larger than R c . By inspecting these and many other persistence curves with different sets of parameters, we conclude that the accelerating role of swaps for a given swap strength U is dramatic when the interaction parameters, R and R c , are sufficiently large so the dynamics is glassy [29], and one is considerably larger than the other. In fact, if the intra-level parameter R and the inter-level parameter R c are very similar, an excitation swap is not more effective than a swap of particles with very similar diameters in a supercooled liquid: the swap would not make the local relaxation significantly easier, as the initial and final configuration would be similarly constrained.…”

“…[21], we also define an intra-level interaction parameter R s = a −1 [2C s α /γ] 1/α (for interactions between atoms in the same excited level s), and an interlevel interaction parameter R ss = a −1 [2C ss α /γ] 1/α (for interactions between atoms in different levels, s and s ). These are microscopic (reduced) lengthscales (normalized by the lattice constant) that parametrize the effective range of intra-level and inter-level interactions, respectively, and they determine the dynamical regime of the system [29]. Moreover, we focus on van der Waals interactions, so the exponents in (14,15) satisfy α = β = 6.…”

Dynamical phase transition to localized states in the two-dimensional random walk conditioned on partial currents

“…In fact, our G min. (J ) is an upper bound of the actual macroscopic functional restricted to a quite limited subset of density and current fields {ρ(r), j(r)} (though qualitatively representative of some of the main features that are observed in the microscopic analysis), as is frequently the case is the analysis of mean-field solutions of dynamical large deviations of manybody systems [35]. Yet, despite its simplicity, our study does provide a sound qualitative understanding of the dynamical regimes under consideration-if not of the nature of the phase transition, which is actually continuous, as explained in the main text.…”

“…The study of DPTs is frequently accomplished in onedimensional systems [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38], where the computation of large deviations for large systems is analytically tractable. Analyses of higher dimensional settings are challenging, since they rely on variational procedures and diagonalization problems whose complexity increases with the spatial dimension.…”

Numerical linked-cluster expansion for the dissipative XYZ model on a triangular lattice

“…In contrast to the equilibrium case, the properties of the dissipative system are featured by the evolved steady state rather than the ground state of the Hamiltonian. Recently, a large body of work has be devoted to investigate the properties of the dissipative quantum many-body systems including the dynamics [2][3][4][5][6], transport properties [7][8][9][10][11], steady-state phases [12][13][14][15]16] and phase transitions [17][18][19][20][21], quantum states engineering [22][23][24], as well as the possible applications in quantum sensing [25,26]. Thanks to the experiment progress, dissipative phase transitions have been observed in circuit QED arrays [27] and ensembles of Rydberg atoms [28,29].…”