Isentropes of spin-1 bosons in an optical lattice

TL;DR

This paper investigates how adiabatic loading affects the temperature of spin-1 bosons in optical lattices, providing isentropes that guide experimental temperature control during phase transitions.

Contribution

It introduces mean-field isentropes for spin-1 bosons in optical lattices across different spin couplings, linking temperature changes to phase boundaries during adiabatic processes.

Findings

Cooling occurs in the superfluid phase during adiabatic loading.

Heating occurs in the Mott insulator phase.

The phase boundary acts as a heating-cooling separatrix.

Abstract

We analyze the effects of adiabatic ramping of optical lattices on the temperature of spin-1 bosons in a homogeneous lattice. Using mean-field theory, we present the isentropes in the temperature-interaction strength ($T,U_0$) plane for ferromagnetic, antiferromagnetic, and zero spin couplings. Following the isentropic lines, temperature changes can be determined during adiabatic loading of current experiments. We show that the heating-cooling separatrix lies on the superfluid-Mott phase boundary with cooling occuring within the superfluid and heating in the Mott insulator, and quantify the effects of spin coupling on the heating rate. We find that the mean-field isentropes for low initial entropy terminate at the superfluid-Mott insulator phase boundary.