Persistent Dark States & Non-Ergodic Chaos in Anisotropic Central Spin Models

Speaker: Tamiro Villazon Scholer, Boston University, Physics Department

When: June 12, 2020 (Fri), 04:00PM to 05:00PM (add to my calendar)

This event is part of the Departmental Seminars.

Dark states, in which a qubit is effectively decoupled from its environment, are pervasive in solid-state systems such as quantum dots and defect centers in diamond. In this seminar, I will present recent work which establishes that dark states are ubiquitous in a large class of inhomogeneous anisotropic central spin models. These models have integrable limits with exact dark eigenstates in which the central qubit is fully polarized. Remarkably, dark states persist as eigenstates in the presence of strong integrability-breaking perturbations, and the qubit retains memory of its initial polarization. Although the eigenstates of the system are chaotic, exhibiting exponential sensitivity to small perturbations, they do not satisfy the eigenstate thermalization hypothesis. This chaotic but non-ergodic regime is found to be stable at numerically accessible system sizes, predicting long relaxation times that increase exponentially with system size. I shall further discuss the implications of these results in mesoscopic applications to dynamic nuclear polarization and quantum memory.

Topic: Departmental Seminar - Tamiro Villazon Time: Jun 12, 2020 03:45 PM Eastern Time (US and Canada)

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