Measurement induced dynamics and defect stabilization in spinor condensates

Publication Date


Document Type



Physics and Astronomy

Publication Title

American Physical Society March Meeting 2019

Conference Location

Boston, MA


Weakly measuring many-body systems and allowing for feedback in real time can simultaneously create and measure new phenomena in quantum systems. We study weak measurement and classical feedback in spinor Bose-Einstein condensates, focusing on the trade-off between usable information obtained from measurement and quantum backaction. As a prototype example, we consider the dynamics of a domain wall in a two-component BEC and 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. Finally, we discuss extensions of this idea to higher spin systems.