Harnessing currents of particles for spectroscopy in small-ring lattices with binary mixtures

Instituto de Física, Facultad de Física, Pontificia Universidad Católica de Chile - Casilla 306, Santiago, Chile

Received: 6 February 2020
Accepted: 6 July 2020

Abstract

We propose a method to probe ground states with distinct properties in binary mixtures trapped in small-ring lattices. The technique exploits the nonequilibrium particle current behavior generated by a nonadiabatic change of the interaction between the species of the binary mixture. The analysis of the current fluctuations in the Fourier space reveals a correspondence between the frequency peaks and specific particle-hole excitations, thereby performing a many-body spectroscopy of the ground state of the system. We show, for a small system, that the read out of the frequency spectrum can be used to detect essential features of a pair superfluid quantum phase. Remarkably, large frequency shifts of the spectral peaks provide an indication of relevant differences between ground states located very near in the parameter space. This spectral behavior allows establishing a criterium to determine in experiments changes in the properties of the ground state in small systems.