Self-Trapping in a Spin-Orbit Coupled Bose-Einstein Condensate
In this talk, I will present work done measuring macroscopic quantum self-trapping and observing a dynamical phase transition in a momentum space Bose-Einstein condensate (BEC). Self-trapping is a hallmark phenomenon of nonlinear systems, and emerges when the interparticle interaction strength dominates the dynamics. It manifests as self-maintaining population imbalance between quantum states where tunneling would otherwise occur given an absence in the nonlinearity. Self-trapping has significant applications in modern physics, including band structure engineering, phase transition dynamics, quantum metrology, and more. To observe macroscopic quantum self-trapping, I employ a Raman induced spin-orbit coupled BEC with a complementary optical lattice to enhance coupling between momentum eigenstates of the system. By ramping the Raman detuning, I investigate the spin dynamics of the system and measure two distinct regimes: a delocalized mixed state regime and a self-trapping regime. I then perform Raman detuning quenches on the system, inducing excited dynamical behavior resulting in oscillations of the system’s spin polarization. Depending on which dynamical regime the system is in, the oscillations are either enhanced or damped, signalling a dynamical phase transition in the system.
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