Quantum Fluctuations in 1d Many-Body Transport: Hydrodynamics and Beyond

Stafano Scopa (King’s College London)

Transport in one-dimensional quantum many-body systems can display very different hydrodynamic regimes, ranging from ballistic propagation in integrable systems to diffusion in stochastic systems. While hydrodynamics provides an effective description of the large-scale evolution of conserved quantities, a natural next question concerns the fluctuations around this macroscopic dynamics, and in particular those retaining quantum-coherent features surviving at large scales.

I will discuss recent results in this direction. I will first focus on inhomogeneous one-dimensional Bose gases, where Generalized Hydrodynamics describes the evolving background state, while quantum fluctuations around it can be formulated in terms of an effective low-energy theory closely related to Luttinger-liquid and conformal-field-theory ideas. This framework gives access to quantities such as long-range correlations and entanglement throughout the nonequilibrium evolution.

I will then briefly discuss the complementary diffusive setting of stochastic quantum many-body systems, where macroscopic fluctuation theory provides the natural large-scale description and raises the question of how quantum-coherent fluctuations can be incorporated beyond its standard classical formulation.

Contact : Z. Ristivojevic