arXiv subjects

Matteo Soriente

Publications and source records attributed to Matteo Soriente.

4 recordsLinked to original sources

arXiv2026

Dissipation-induced superradiance in matter coupled to a self-interacting cavity

Light-matter interactions are often modeled via the Dicke model, namely, by two-level systems coupled to a cavity mode. Alas, the threshold for superradiance is often experimentally inaccessible or hindered by light's diamagnetic term. Here, within the Dicke setting, we consider self-interacting light in a cavity, modeled by a photonic Kerr nonlinearity. We show that negative Kerr nonlinearity gives rise to a low-threshold superradiant phase with spin inversion. While unstable in a closed system, cavity dissipation stabilizes this lit phase, opening avenues for lasing and bath-engineered phases.

quant-ph↗

arXiv2021

Emerging dissipative phases in a superradiant quantum gas with tunable decay

Exposing a many-body system to external drives and losses can transform the nature of its phases and opens perspectives for engineering new properties of matter. How such characteristics are related to the underlying microscopic processes of the driven and dissipative system is a fundamental question. Here we address this point in a quantum gas that is strongly coupled to a lossy optical cavity mode using two independent Raman drives, which act on the spin and motional degrees of freedom of the atoms. This setting allows us to control the competition between coherent dynamics and dissipation by adjusting the imbalance between the drives. For strong enough coupling, the transition to a superradiant phase occurs, as is the case for a closed system. Yet, by imbalancing the drives we can enter a dissipation-stabilized normal phase and a region of multistability. Measuring the properties of excitations on top of the out-of-equilibrium phases reveals the microscopic elementary processes in the open system. Our findings provide prospects for studying squeezing in non-Hermitian systems, quantum jumps in superradiance, and dynamical spin-orbit coupling in a dissipative setting.

cond-mat.quant-gas↗

arXiv2021

Distinctive class of dissipation-induced phase transitions and their universal characteristics

Coupling a system to a nonthermal environment can profoundly affect the phase diagram of the closed system, giving rise to a special class of dissipation-induced phase transitions. Such transitions take the system out of its ground state and stabilize a higher-energy stationary state, rendering it the sole attractor of the dissipative dynamics. In this work, we present a unifying methodology, which we use to characterize this ubiquitous phenomenology and its implications for the open system dynamics. Specifically, we analyze the closed system's phase diagram, including symmetry-broken phases, and explore their corresponding excitations' spectra. Opening the system, the environment can overwhelm the system's symmetry-breaking tendencies, and changes its order parameter. As a result, isolated distinct phases of similar order become connected, and new phase-costability regions appear. Interestingly, the excitations differ in the newly-connected regions through a change in their symplectic norm, which is robust to the introduction of dissipation. As a result, by tuning the system from one phase to the other across the dissipation-stabilized region, the open system fluctuations exhibit an exceptional point-like scenario, where the fluctuations become overdamped, only to reappear with an opposite sign in the dynamical response function of the system. The overdamped region is also associated with squeezing of the fluctuations. We demonstrate the pervasive nature of such dissipation-induced phenomena in two prominent examples, namely in parametric resonators and in light-matter systems. Our work draws a crucial distinction between quantum phase transitions and their zero-temperature open system counterparts.

quant-ph↗

arXiv2017

Dissipation-induced anomalous multicritical phenomena

We explore the influence of dissipation on a paradigmatic driven-dissipative model where a collection of two level atoms interact with both quadratures of a quantum cavity mode. The closed system exhibits multiple phase transitions involving discrete and continuous symmetries breaking and all phases culminate in a multicritical point. In the open system, we show that infinitesimal dissipation erases the phase with broken continuous symmetry and radically alters the model's phase diagram. The multicritical point now becomes brittle and splits into two tricritical points where first- and second-order symmetry-breaking transitions meet. A quantum fluctuations analysis shows that, surprisingly, the tricritical points exhibit anomalous finite fluctuations, as opposed to standard tricritical points arising in $^3He-\text{}^4He$ mixtures. Our work has direct implications for a variety of fields, including cold atoms and ions in optical cavities, circuit-quantum electrodynamics as well as optomechanical systems.

cond-mat.quant-gas↗