Universality is a powerful concept, which enables making qualitative and quantitative
predictions in systems with extensively many degrees of freedom. It finds realizations in …

Turbulent phenomena are among the most striking effects that both classical and quantum
fluids can exhibit. Although classical turbulence is ubiquitous in nature, the observation of …

The statistics of the fluctuations of quantum many-body systems are highly revealing of their
nature. In driven-dissipative systems displaying macroscopic quantum coherence, as …

We consider a one-dimensional driven-dissipative exciton-polariton condensate under
incoherent pump, described by the stochastic generalized Gross-Pitaevskii equation. It was …

The emergence of macroscopic coherence in a many-body quantum system is a ubiquitous
phenomenon across different physical systems and scales. This Chapter reviews key …

Numerical simulations of the full quantum properties of interacting many-body systems by
means of field-theoretic Monte Carlo techniques are often limited due to a sign problem …

Phase fluctuations determine the low-energy properties of quantum condensates. However,
at the condensation threshold, both density and phase fluctuations are relevant. While …

We experimentally explore the rich variety of nonlinear coherent structures arising in a
turbulent flow of superfluid light past an obstacle in an all-optical configuration. The different …

We report first-order spatial and temporal correlations in strongly coupled plasmonic Bose-
Einstein condensates. The condensate is large, more than 20 times the spatial coherence …

We study a four-component polariton system in the optical parametric oscillator regime
consisting of exciton, photon, signal, and idler modes across the Berezinskii-Kosterlitz …