A particle in an Anderson-localized system, if launched in any direction, should on average return to its starting point and stay there. Despite the central role played by Anderson localization in the modern understanding of condensed matter, this "quantum boomerang" effect, an essential feature of the localized state, was only recently theoretically predicted and has not previously been observed. We report the experimental observation of the quantum boomerang effect. Using a degenerate gas and a phase-shifted pair of optical lattices, we probe the role of time reversal symmetry breaking, Floquet gauge, and initial state symmetry in supporting or disrupting the boomerang effect. Highlighting the key role of localization, we observe that as stochastic kicking destroys dynamical localization, the quantum boomerang effect also disappears. Measured dynamics are in agreement with analytical and numerical predictions. These results showcase a unique experimental probe of the underlying quantum nature of Anderson localized matter.
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Publication: Sajjad et al., Observation of the quantum boomerang effect (2021), arXiv:2109.00696 [cond-mat.quant-gas]
Presenters
Roshan Sajjad
University of California, Santa Barbara
Authors
Roshan Sajjad
University of California, Santa Barbara
Jeremy Tanlimco
University of California, Santa Barbara
Hector Mas
University of California, Santa Barbara
Alec J Cao
University of Cambridge, University of California, Santa Barbara
Eber Nolasco-Martinez
University of California, Santa Barbara
Ethan Q Simmons
University of California, Santa Barbara
Flavio Santos
Universidade Federal do Rio Grande do Norte
Patrizia Vignolo
Universit´e Cˆote d'Azur, CNRS, Institut de Physique de Nice
