Aydin Deger

University of Oxford | OX · Department of Physics

We study the stability of localization under periodic driving in Stark many-body systems. We find that localization is stable except near special resonant frequencies, where resonances cause delocalization. We provide approximate analytical arguments and numerical evidence in support of these results. This shows that disorder-free broken ergodicity...

Experiments in Rydberg atoms have recently found unusually slow decay from a small number of special initial states. We investigate the robustness of such long-lived states (LLS) by studying an ensemble of locally constrained random systems with tunable range μ . Upon varying μ , we find a transition between thermal and weakly nonergodic (supportin...

In the curved spacetime of a black hole, quantum physics gives rise to distinctive effects such as Hawking radiation. Here, we present a scheme for an analogue quantum simulation of (1 + 1)-dimensional black holes using ultracold atoms in a locally Floquet-driven 1D optical lattice. We show how the effective dynamics of the driven system can genera...

Gaussian correlations emerge in a large class of many-body quantum systems quenched out of equilibrium, as demonstrated in recent experiments on coupled one-dimensional superfluids [Schweigler et al., Nat. Phys. 17, 559 (2021)]. Here we present a mechanism by which an initial state of a Rydberg atom array can retain persistent non-Gaussian correlat...

Experiments in Rydberg atoms have recently found unusually slow decay from a small number of special initial states. We investigate the robustness of such long-lived states (LLS) by studying an ensemble of locally constrained random systems with tunable range µ. Upon varying µ, we find a transition between a thermal and a weakly non-ergodic (suppor...

One of the key applications of AdS/CFT correspondence is the duality it dictates between the entanglement entropy of anti–de Sitter (AdS) black holes and lower-dimensional conformal field theories (CFTs). Here we employ a square lattice of fermions with inhomogeneous tunneling couplings that simulate the effect rotationally symmetric three-dimensio...

Gaussian correlations emerge in a large class of many-body quantum systems quenched out of equilibrium, as demonstrated in recent experiments on coupled one-dimensional superfluids [Schweigler et al., Nature Physics 17, 559 (2021)]. Here, we present a mechanism by which an initial state of a Rydberg atom array can retain persistent non-Gaussian cor...

The AdS/CFT correspondence has been insightful for high-energy and condensed matter physics alike. An application of this correspondence is the duality between the entanglement entropy of Anti-de Sitter (AdS) black holes and lower-dimensional conformal field theories (CFT). To explicitly demonstrate this correspondence we simulate the effect a 3D b...

The AdS/CFT correspondence has been insightful for high-energy and condensed matter physics alike. An application of this correspondence is the duality between the entanglement entropy of Anti-de Sitter (AdS) black holes and lower-dimensional conformal field theories (CFT). To explicitly demonstrate this correspondence we simulate the effect a 3D b...

In a recent work [A. Deger et al., Phys. Rev. Lett. 129, 160601 (2022).] we have shown that kinetic constraints can completely arrest many-body chaos in the dynamics of a classical, deterministic, translationally invariant spin system with the strength of the constraint driving a dynamical phase transition. Using extensive numerical simulations and...

We investigate the effect of kinetic constraints on classical many-body chaos in a translationally invariant Heisenberg spin chain using a classical counterpart of the out-of-time-ordered correlator (OTOC). The strength of the constraint drives a “dynamical phase transition” separating a delocalized phase, where the classical OTOC propagates ballis...

In a recent work [A. Deger et al., Phys. Rev. Lett. 129, 160601 (2022)] we have shown that kinetic constraints can completely arrest many-body chaos in the dynamics of a classical, deterministic, translationally-invariant spin system with the strength of the constraint driving a dynamical phase transition. Using extensive numerical simulations and...

Phase transitions occur in a wide range of physical systems and are characterized by the abrupt change of a physical observable in response to the variation of an external control parameter. Phase transitions are not restricted to equilibrium situations but can also be found in nonequilibrium settings, both for classical and quantum mechanical syst...

We investigate the effect of kinetic constraints on classical many-body chaos in a translationally-invariant Heisenberg spin chain using a classical counterpart of the out-of-time-ordered correlator (OTOC). The strength of the constraint drives a 'dynamical phase transition' separating a delocalised phase, where the classical OTOC propagates ballis...

Phase transitions occur in a wide range of physical systems and are characterized by the abrupt change of a physical observable in response to the variation of an external control parameter. Phase transitions are not restricted to equilibrium situations but can also be found in non-equilibrium settings, both for classical and quantum mechanical sys...

Systems of interacting fermions can give rise to ground states whose correlations become effectively free-fermion-like in the thermodynamic limit, as shown by Baxter for a class of integrable models that include the one-dimensional XYZ spin-12 chain. Here, we quantitatively analyze this behavior by establishing the relation between system size and...

Dynamical phase transitions extend the notion of criticality to nonstationary settings and are characterized by sudden changes in the macroscopic properties of time-evolving quantum systems. Investigations of dynamical phase transitions combine aspects of symmetry, topology, and nonequilibrium physics; however, progress has been hindered by the not...

Systems of interacting fermions can give rise to ground states whose correlations become effectively free-fermion-like in the thermodynamic limit, as shown by Baxter for a class of integrable models that include the one-dimensional XYZ spin-$\frac{1}{2}$ chain. Here, we quantitatively analyse this behaviour by establishing the relation between syst...

Dynamical phase transitions extend the notion of criticality to non-stationary settings and are characterized by sudden changes in the macroscopic properties of time-evolving quantum systems. Investigations of dynamical phase transitions combine aspects of symmetry, topology, and non-equilibrium physics, however, progress has been hindered by the n...

We investigate the Ising model in one, two, and three dimensions using a cumulant method that allows us to determine the Lee-Yang zeros from the magnetization fluctuations in small lattices. By doing so with increasing system size, we are able to determine the convergence point of the Lee-Yang zeros in the thermodynamic limit and thereby predict th...

Phase transitions are typically accompanied by nonanalytic behaviors of the free energy, which can be explained by considering the zeros of the partition function in the complex plane of the control parameter and their approach to the critical value on the real axis as the system size is increased. Recent experiments have shown that partition funct...

We investigate the Ising model in one, two, and three dimensions using a cumulant method that allows us to determine the Lee-Yang zeros from the magnetization fluctuations in small lattices. By doing so with increasing system size, we are able to determine the convergence point of the Lee-Yang zeros in the thermodynamic limit and thereby predict th...

Phase transitions are typically accompanied by non-analytic behaviors of the free energy, which can be explained by considering how the zeros of the partition sum for complex values of the control parameter approach the critical value in the thermodynamic limit. Recent experiments have shown that partition function zeros are not just a theoretical...

In this work, we investigate quantum phase transition (QPT) in a generic family of spin chains using the geometric measure of entanglement (GE). In many of prior works, GE per site was used. Here, we also consider GE per block with each block size being two. This can be regarded as a coarse grain of GE per site. We introduce a useful parameterizati...

Lee-Yang zeros are points in the complex plane of an external control parameter at which the partition function vanishes for a many-body system of finite size. In the thermodynamic limit, the Lee-Yang zeros approach the critical value on the real axis, where a phase transition occurs. Partition function zeros have for many years been considered a p...

Lee-Yang zeros are complex values of an external control parameter at which the partition function vanishes for a many-body system of finite size. In the thermodynamic limit, the Lee-Yang zeros approach the critical value on the real-axis where a phase transition occurs. Partition function zeros have for many years been considered a purely theoreti...

The complex zeros of partition functions were originally investigated by Lee and Yang to explain the behavior of condensing gases. Since then, Lee-Yang zeros have become a powerful tool to describe phase transitions in interacting systems. Today, Lee-Yang zeros are no longer just a theoretical concept; they have been determined in recent experiment...