An isolated quantum gas with a localized loss features nonmonotonic behavior of the particle rate as an incarnation Zeno effect, recently shown in experiments cold atomic gases. While this effect can be understood terms local, microscopic physics, we show that novel many-body effects emerge when nonlinear gapless fluctuations become important. To end, investigate local dissipative impurity on one-dimensional interacting fermions. We escape probability for modes close to Fermi energy vanishes...

Abstract Quantum spin liquids provide paradigmatic examples of highly entangled quantum states matter. Frustration is the key mechanism to favor over more conventional magnetically ordered states. Here we propose engineer frustration by exploiting coupling magnets quantized light an optical cavity. The interplay between fluctuations electro-magnetic field and strongly correlated electrons results in a tunable long-range interaction localized spins. This cavity-induced robustly stabilizes...

Extended quantum systems can be theoretically described in terms of the Schwinger-Keldysh functional integral formalism, whose action conveniently describes both dynamical and static properties. We show here that thermal equilibrium, defined by validity fluctuation-dissipation relations, a system is invariant under certain symmetry transformation, thus it distinguished from generic systems. In turn, relations derived as Ward-Takahashi identities associated with this symmetry. Accordingly,...

Renormalization-group methods provide a viable approach for investigating the emergent collective behavior of classical and quantum statistical systems in both equilibrium nonequilibrium conditions. Within this we investigate here dynamics an isolated system represented by scalar ${\ensuremath{\phi}}^{4}$ theory after global quench potential close to dynamical critical point. We demonstrate that, within prethermal regime, time dependence relevant correlations is characterized short-time...

The nonequilibrium dynamics of an isolated quantum system after a sudden quench to dynamical critical point is expected be characterized by scaling and universal exponents due the absence time scales. We explore these features for parameters Hamiltonian with O(N) symmetry, starting from ground state in disordered phase. In limit infinite N, forms relevant two-time correlation functions can calculated exactly. Our analytical predictions are confirmed numerical solution corresponding...

We study the prethermal dynamics of an interacting quantum field theory with N-component order parameter and O(N) symmetry, suddenly quenched in vicinity a dynamical critical point. Depending on initial conditions, evolution parameter, response correlation functions, can exhibit temporal crossover between universal scaling regimes governed, respectively, by classical fixed point, as well from Gaussian to non-Gaussian scaling. Together recent experiment, this suggests that quenches may be...

The effect of localized loss on a one-dimensional gas interacting fermions is investigated. Here, the interplay gapless quantum fluctuations and particle interactions strongly renormalizes dissipative impurity. As result, probability for modes close to Fermi energy vanishes arbitrary strength dissipation, as many-body incarnation Zeno effect. This reflected in shape momentum distribution, exhibiting peak momentum.

The physics of long-range interacting quantum systems is currently living through a renaissance driven by the fast progress in simulators. In these many paradigms statistical do not apply and also universal long-wavelength gets substantially modified presence long-ranged forces. Here we explore low-energy excitations several systems, including spin models Bose gases, ordered phase associated with spontaneous breaking U(1) SU(2) symmetries. Instead expected Goldstone modes, find three...

We develop a generic phenomenological model to describe the fluctuations on top of non-equilibrium Bose-Einstein condensate. Analytic expressions are obtained for momentum distribution non-condensed cloud and long-distance behavior spatial coherence in different dimensionalities. Comparison our predictions with available experimental data condensates exciton-polaritons surface-emitting planar laser devices is finally made.

We investigate the effects of fluctuations on dynamics an isolated quantum system represented by a $\phi^4$ field theory with $O(N)$ symmetry after quench in $d>2$ spatial dimensions. A perturbative renormalization-group approach involving dimensional expansion $\epsilon=4-d$ is employed order to study evolution within prethermal regime controlled elastic dephasing. In particular, we focus from disordered initial state critical point, which introduces effective temporal boundary evolution....

We develop a quantum model for non-equilibrium Bose-Einstein condensation of photons and polaritons in planar microcavity devices. The builds upon laser theory includes the spatial dynamics cavity field, saturation mechanism some frequency-dependence gain: Langevin equations are written field coupled to continuous distribution externally pumped two-level emitters with well-defined frequency. As an example application, method is used study linearised fluctuations around steady-state condensed...

We study the thermalization and Bose-Einstein condensation of a paraxial, spectrally narrow beam quantum light propagating in lossless bulk Kerr medium. The spatiotemporal evolution optical field is ruled by Heisenberg equation analogous to nonlinear Schr\"odinger dilute atomic Bose gases. Correspondingly, weak-nonlinearity regime, phase-space density evolves according Boltzmann equation. Expressions for time temperature chemical potential eventual distribution are found. After discussing...

We present a method to calculate short-time nonequilibrium universal exponents within the functional-renormalization-group scheme. As an example, we consider classical critical dynamics of relaxational model A after quench temperature system and initial-slip exponent which characterizes behavior both order parameter correlation functions. The value this is found be consistent with result perturbative dimensional expansion Monte Carlo simulations in three spatial dimensions.

We study the effects of spacial structure localized losses in weakly-interacting fermionic quantum wires. show that multiple dissipative impurities give rise to resonant visible transport properties and particles' momentum distribution. These resonances can enhance or suppress effective particle wire. Moreover, we investigate interplay between interactions impurity shape find that, differently from coherent scatterer case, modifies scaling scattering probabilities close Fermi momentum. while...

We investigate the finite-size origin of coherence time (or equivalently its inverse, emission linewidth) a spatially extended, one-dimensional nonequilibrium condensate. show that well-known Schawlow-Townes scaling laser theory, possibly including Henry broadening factor, only holds for small system sizes, while in larger systems linewidth displays novel determined by Kardar-Parisi-Zhang physics. This is shown to lead an opposite dependence on optical nonlinearity two cases. then study how...

In bosonic gases at thermal equilibrium, an external quadratic drive can induce a Bose-Einstein condensation described by the Ising transition, as consequence of explicitly broken U(1) phase rotation symmetry down to Z_{2}. However, in physical realizations such exciton polaritons and nonlinear photonic lattices, equilibrium is lost state rather determined balance between losses drive. A fundamental question then how nonequilibrium fluctuations affect this transition. Here, we show that...

The authors use optical excitation as a way to alter the magnetic free energy landscape and resulting phase diagram of frustrated honeycomb magnet $\ensuremath{\alpha}$-RuCl${}_{3}$. They time-track experimentally magneto-optical response from $\ensuremath{\alpha}$-RuCl${}_{3}$'s zigzag-ordered ground state after photoexcitation they reproduce observed dynamics within Ginzburg-Landau model. A quasistationary spin disordered is induced above critical density, suggesting new route reach...

We investigate the transport properties of a quantum wire weakly interacting fermions in presence local particle loss. calculate current and conductance this system due to applied external chemical potential bias that can be measured experimental realizations ultracold quasi one-dimensional traps. Using Keldysh field theory approach based on Lindblad equation, we establish perturbative scheme study effect imbalanced reservoirs. Logarithmically divergent terms are resummed using...

We investigate a pseudothermalization effect, where an open quantum system coupled to nonequilibrated environment consisting of several non-Markovian reservoirs presents emergent thermal behavior. This behavior is visible at both static and dynamical levels the satisfies fluctuation-dissipation theorem. Our analysis focused on exactly solvable model weakly interacting driven-dissipative Bose gas in presence frequency-dependent particle pumping losses, based Langevin theory, which we derive...

We investigate the nonequilibrium dynamics of a class isolated one-dimensional systems possessing two degenerate ground states, initialized in low-energy symmetric phase. report emergence timescale separation between fast (radiation) and slow (kink or domain wall) degrees freedom. find universal long-time dynamics, largely independent microscopic details system, which kinks control relaxation relevant observables correlations. The resulting late-time can be described by set phenomenological...

We investigate the impact of an Ohmic-class environment on conduction and correlation properties one-dimensional interacting systems. Interestingly, we reveal that inter-particle interactions can be engineered by environment's noise statistics. Introducing a backscattering impurity to system, address Kane-Fisher's metal-to-insulator quantum phase transition in this noisy realistic setting. Within perturbative renormalization group approach, show Ohmic environments keep intact, while sub-...

Excitons in two-dimensional semiconductors provide a novel platform for fundamental studies of many-body interactions. In particular, dipolar interactions between spatially indirect excitons may give rise to strongly correlated phases matter that so far have been out reach experiments. Here we show excitonic few-body systems atomically thin transition-metal dichalcogenides confined one-dimensional geometry undergo crossover from Tonks-Girardeau charge density wave regime. To this end, take...

After reviewing the interpretation of laser operation as a non-equilibrium Bose-Einstein condensation phase transition, we illustrate novel features arising from nature photon and polariton condensates recently observed in experiments. We then proposea quantitative criterion to experimentally assess equilibrium vs. specific process, based on fluctuation-dissipation relations. The power this is illustrated two models which shows very different behaviours.