Periodic driving control of Raman-induced spin-orbit coupling in Bose-Einstein condensates: the heating mechanisms

TL;DR

This paper investigates heating mechanisms in periodically driven Raman-induced spin-orbit coupling in Bose-Einstein condensates, identifying key sources of heating and suggesting strategies to mitigate them for improved control.

Contribution

It provides a detailed analysis of heating processes in Floquet-engineered SOC systems, highlighting population transfer to excited states and non-adiabatic effects as main issues.

Findings

Main heating due to population transfer to excited states

Additional heating from non-adiabatic parameter variation

Analytical insights for reducing heating effects

Abstract

We focus on a technique recently implemented for controlling the magnitude of synthetic spin-orbit coupling (SOC) in ultra-cold atoms in the Raman-coupling scenario. This technique uses a periodic modulation of the Raman-coupling amplitude to tune the SOC. Specifically, it has been shown that the effect of a high-frequency sinusoidal modulation of the Raman-laser intensity can be incorporated into the undriven Hamiltonian via effective parameters, whose adiabatic variation can then be used to steer the SOC. Here, we characterize the heating mechanisms that can be relevant to this method. We identify the main mechanism responsible for the heating observed in the experiments as basically rooted in driving-induced transfer of population to excited states. Characteristics of that process determined by the harmonic trapping, the decay of the excited states, and the technique used for preparing the system are discussed. Additional heating, rooted in departures from adiabaticity in the variation of the effective parameters, is also described. Our analytical study provides some clues that may be useful in the design of strategies for curbing the effects of heating on the efficiency of the control methods.