Measurement induced dynamics and stabilization of spinor condensate domain walls

TL;DR

This paper investigates how continuous measurement and feedback influence the dynamics and stabilization of domain walls in a two-component Bose-Einstein condensate, revealing measurement-induced effects like diffusion and heating, and demonstrating feedback-based stabilization.

Contribution

It introduces a feedback protocol to create and stabilize domain walls in regimes where they are normally unstable, showcasing Hamiltonian engineering through measurement and feedback.

Findings

Measurement causes domain wall diffusion and heating.

System dynamics depend on measurement observable.

Feedback protocol stabilizes domain walls in unstable regimes.

Abstract

Weakly measuring many-body systems and allowing for feedback in real-time can simultaneously create and measure new phenomena in strongly correlated quantum systems. We study the dynamics of a continuously measured two-component Bose-Einstein condensate (BEC) potentially containing a domain wall, and focus on the trade-off between usable information obtained from measurement and quantum backaction. Each weakly measured system yields a measurement record from which we extract real-time dynamics of the domain wall. We show that quantum backaction due to measurement causes two primary effects: domain wall diffusion and overall heating. The system dynamics and signal-to-noise ratio depend on the choice of measurement observable. We describe a feedback protocol to create and stabilize a domain wall in the regime where domain walls are unstable, giving a prototype example of Hamiltonian engineering using measurement and feedback.