The quantum boomerang effect
Seminars | Wednesday, July 05, 2023 | 11:00:00
Speaker:Recently, a novel manifestation of Anderson localization for wave packets launched with a finite velocity was proposed, the Quantum boomerang effect (QBE). This phenomenon predicts that the disorder-averaged center of mass of a particle initially moves ballistically, then makes a U-turn, and slowly returns to its initial position. Time-reversal (T) symmetry of the Hamiltonian was believed to be crucial for the existence of the QBE, which was numerically found in several models with such symmetry. In this talk I will show sufficient conditions that lead to the presence of the QBE in a wide class of disordered systems, including models without T symmetry. We numerically confirm our analytical predictions and show the QBE in lattice models breaking T symmetry through magnetic field. We also investigate several Hermitian and non-Hermitian models. Finally, we discuss about the first observation of the QBE, done in an experiment simulating the quantum kicked rotor model. The experiment, which used a BEC and a phase-shifted pair of optical lattices, not only verified the QBE but also confirmed the importance of symmetries and of localization in the system.
[1] F. Noronha and T. Macrì, Ubiquity of the quantum boomerang effect in Hermitian Anderson-localized systems, Phys. Rev. B 106, L060301 (2022).
[2] F. Noronha, J. A. S. Lourenço, and T. Macrì, Robust quantum boomerang effect in non-Hermitian systems, Phys. Rev. B 106, 104310 (2022).
[3] R. Sajjad, J. L. Tanlimco, H. Mas, A. Cao, E. Nolasco-Martinez, E. Q. Simmons, F. L. N. Santos, P. Vignolo, T. Macrì, and D. M. Weld, Observation of the Quantum Boomerang Effect, Phys. Rev. X 12, 011035 (2022).
