IQIM Postdoctoral and Graduate Student Seminar

Abstract: The time evolution of a driven quantum system can be strongly affected by dissipation. Although this mainly implies that the system relaxes to a steady state, in some cases it can lead to the appearance of new phases and trigger emergent dynamics. In our experiment, we study a Bose-Einstein condensate dispersively coupled to a high finesse optical resonator. The cavity is populated by scattering photons from a transverse drive illuminating the atoms. The sum of the drive and the self-consistent intracavity field provides a topological band structure. When the dissipative and coherent timescales are comparable, we find a regime of persistent oscillations where the cavity field does not reach a steady state: The emergence of an exceptional point. In this regime the atoms experience a potential that periodically deforms itself, even in the absence of an external time-dependent drive. Consequently, the dynamic lattice triggers topological pumping [1]. We show complementary measurements of the light field and of the atomic transport, proving the connection between the non-stationarity and the topological pumping.
[1] Dreon D, Baumgärtner A, Li X, Hertlein S, Esslinger T & Donner T: Self-oscillating pump in a topological dissipative atom–cavity system. Nature 608, 494–498 (2022)

Lunch will be provided, following the talk, on the lawn north of the Bridge Arcade

Attendees joining in person must demonstrate that they comply with Caltech's vaccination requirements (present Caltech ID or AWS ID or vaccination and booster confirmation).