Ultracold Atoms Out of Equilibrium

Langen, Tim; Geiger, Rémi; Schmiedmayer, Jörg

doi:10.1146/annurev-conmatphys-031214-014548

Cited by 327 publications

(330 citation statements)

References 161 publications

(200 reference statements)

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“…This question is central to the dynamics of a wide variety of experimental and theoretical systems, from cold atoms and condensed matter to quantum chaos and black holes (see for example [1][2][3][4][5][6][7] and [8][9][10][11][12][13][14]). …”

Section: Introductionmentioning

confidence: 99%

Entanglement scrambling in 2d conformal field theory

Asplund

Bernamonti

Galli

et al. 2015

J. High Energ. Phys.

159

270

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Abstract:We investigate how entanglement spreads in time-dependent states of a 1+1 dimensional conformal field theory (CFT). The results depend qualitatively on the value of the central charge. In rational CFTs, which have central charge below a critical value, entanglement entropy behaves as if correlations were carried by free quasiparticles. This leads to long-term memory effects, such as spikes in the mutual information of widely separated regions at late times. When the central charge is above the critical value, the quasiparticle picture fails. Assuming no extended symmetry algebra, any theory with c > 1 has diminished memory effects compared to the rational models. In holographic CFTs, with c 1, these memory effects are eliminated altogether at strong coupling, but reappear after the scrambling time t β log c at weak coupling.

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Section: Introductionmentioning

confidence: 99%

Entanglement scrambling in 2d conformal field theory

Asplund

Bernamonti

Galli

et al. 2015

J. High Energ. Phys.

159

270

View full text Add to dashboard Cite

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“…Among all, the recent technological developments in atomic and condensed matter physics offer a very promising platform to investigate these important issues. Nowadays it is indeed possible to prepare a quantum system in a given non-equilibrium state and to study its evolution in real time, for instance by using cold atoms [11][12][13][14][15], trapped ions [16][17][18], or even quantum conductors in solid-state devices [19,20]. An intriguing possibility to drive a quantum system out of equilibrium is to perform a quantum quench, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…a sudden change in time of some of its parameters [21][22][23]. Such a procedure is available in state-of-the-art systems of cold atoms [11], in which transport and real-time control experiments have been recently reported [13][14][15][24][25][26]. The possibilities offered by the latter setups have given a significant boost to theoretical research, especially in the case of isolated one-dimensional (1D) integrable systems.…”

Section: Introductionmentioning

confidence: 99%

Quench-induced entanglement and relaxation dynamics in Luttinger liquids

et al. 2017

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We investigate the time evolution towards the asymptotic steady state of a one dimensional interacting system after a quantum quench. We show that at finite times the latter induces entanglement between right-and left-moving density excitations, encoded in their cross-correlators, which vanishes in the long-time limit. This behavior results in a universal time-decay ∝ t −2 of the system spectral properties, in addition to non-universal power-law contributions typical of Luttinger liquids. Importantly, we argue that the presence of quench-induced entanglement clearly emerges in transport properties, such as charge and energy currents injected in the system from a biased probe, and determines their long-time dynamics. In particular, the energy fractionalization phenomenon turns out to be a promising platform to observe the universal power-law decay ∝ t −2 induced by entanglement and represents a novel way to study the corresponding relaxation mechanism.

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“…In the second regime, α > 1, the contribution from C (2) converges to a non-zero value for N → ∞, yielding an additional α-dependent shift.…”

mentioning

confidence: 99%

Direct Observation of Dynamical Quantum Phase Transitions in an Interacting Many-Body System

et al. 2017

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Dynamical quantum phase transitions (DQPTs) extend the concept of phase transitions and thus universality to the non-equilibrium regime. In this letter, we investigate DQPTs in a string of ions simulating interacting transverse-field Ising models. We observe non-equilibrium dynamics induced by a quantum quench and show for strings of up to 10 ions the direct detection of DQPTs by measuring a quantity that becomes non-analytic in time in the thermodynamic limit. Moreover, we provide a link between DQPTs and the dynamics of other relevant quantities such as the magnetization, and we establish a connection between DQPTs and entanglement production.Today, the equilibrium properties of quantum matter are theoretically described with remarkable success. Yet, in recent years pioneering experiments have created novel quantum states beyond this equilibrium paradigm [1,2]. Thanks to this progress, it is now possible to experimentally study exotic phenomena such as many-body localization [3,4], prethermalization [5, 6], particle-antiparticle production in the lattice Schwinger model [7], and light-induced superconductivity [8]. Understanding general properties of such nonequilibrium quantum states provides a significant challenge, calling for new concepts that extend important principles such as universality to the non-equilibrium realm. A general approach towards this major goal is the theory of dynamical quantum phase transitions (DQPTs) [9], which extends the concept of phase transitions and thus universality to the nonequilibrium regime. In this letter, we directly observe the defining real-time non-analyticities at DQPTs in a trappedion quantum simulator for interacting transverse-field Ising models. Moreover, we provide a link between DQPTs and the dynamics of other relevant quantities such as the magnetization, and we establish a connection between DQPTs and entanglement production. Our work advances towards experimentally characterizing nonequilibrium quantum states and their dynamics, by offering general experimental tools that can be applied also to other inherently dynamical phenomena.Statistical mechanics and thermodynamics provide us with an excellent understanding of equilibrium quantum manybody systems. A key concept in this framework is the canonical partition function Z(T ) = Tr(e −H/k B T ), with T the temperature, k B the Boltzmann constant, and H the system Hamiltonian. The partition function encodes thermodynamics via the free-energy density f = −(k B T/N) log [Z(T )], where N de- * Present address:ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, University of Sydney, NSW, 2006, Australia notes the number of degrees of freedom. A phase transition, i.e., a sudden change of macroscopic behaviour, is associated with a non-analytical behaviour of f as a function of temperature or another control parameter g such as an external magnetic field. Quantum phase transitions (QPTs) [10] occur when T is kept at absolute zero, where the system's groundstate properties undergo a non-analyt...

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Ultracold Atoms Out of Equilibrium

Cited by 327 publications

References 161 publications

Entanglement scrambling in 2d conformal field theory

Entanglement scrambling in 2d conformal field theory

Quench-induced entanglement and relaxation dynamics in Luttinger liquids

Direct Observation of Dynamical Quantum Phase Transitions in an Interacting Many-Body System

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