Double-weak-link interferometer of hard-core bosons in one dimension

TL;DR

This paper investigates quantum interference effects in a one-dimensional hard-core boson gas with two weak links, revealing deviations from hydrodynamic predictions through exact fermionic analysis.

Contribution

It provides an exact analytic expression for the density profile during expansion, highlighting interference effects beyond hydrodynamic models.

Findings

Interference fringes arise from repeated reflections at the defects.

Density profiles deviate from hydrodynamic predictions due to quantum interference.

Exact fermionic propagators reveal coherent patterns beyond classical descriptions.

Abstract

We study the dynamics of a lattice hard-core boson gas released from a domain wall initial state in the presence of two weak links (defects). When the two defects are separated by a finite distance, the resulting density profile exhibits clear deviations from the standard Euler-scale hydrodynamic description of the gas, due to genuine quantum interference effects between the two defects. By analyzing the exact fermionic propagators, we show that repeated reflections at the defects give rise to interference fringes and coherent patterns that are beyond the reach of the (generalized) hydrodynamic description. We derive a closed analytic expression for the density profile during the expansion, explicitly highlighting the role played by these interference processes.