Dissipation of energy occurs naturally when a particle with finite momentum moves through a medium. Typically, the momentum of the particle is assumed to be decoupled from its spin degrees of freedom. However, this is not the case for many condensed matter systems with strong spin-orbit coupling (SOC). To understand equilibration processes in these systems and eventually exploit them in technological application of spintronics, studies of dissipative dynamics with SOC are needed.Cold-atom-based quantum simulators have increasingly stood out as a natural test bed for such studies.
In this talk, we are going to present a model, based on an extension of the Caldeira-Leggett framework for quantum Brownian motion, exploring the dynamical features of a spin-orbit coupled impurity [1]. By mainly focusing on a 1D setup, we first benchmark our model against available experimental [2], still lacking a convincing theoretical explanation. We actually show that our framework contains all ingredients to describe the observed breathing dynamics of the impurity assuming that the initial condition is the (only) tunable parameter. The calculations are analytical, thus simplifying the analysis and allowing us to gain insight into the system: relevant timescales,short- and long-time dynamics. Finally, we explore the dynamics of the system with SOC. Without magnetic fields, the 1D SOC can be gauged out so the system can be described using the Caldeira-Leggett equation with SOC-dependent initial conditions. We present observables that are sensitive to these initial conditions and can be used to study the effect of SOC on time dynamics, for example, formation of regions with steady spin polarization.
[1] A. Ghazaryan, A. Cappellaro, M. Lemeshko and A. G. Volosniev, Dissipative Dynamics of an impurity with spin-orbit coupling, Phys. Rev. Res. 5, 013029 (2023).
[2] J. Catani, G. Lamporesi, D. Naik, M. Gring, M. Inguscio, F. Minardi, A. Kantian, and T. Giamarchi, Quantum dynamics of impurities in a one-dimensional Bose gas, Phys. Rev. A 85, 023623 (2012).
Prof. Luca Salasnich
