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arXiv · 1808.01287

Population inversion and dynamical phase transitions in a driven superconductor

H. P. Ojeda Collado·José Lorenzana·Gonzalo Usaj·C. A. Balseiro
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Abstract

We consider a superconductor in which the density of states at the Fermi level or the pairing interaction is driven periodically with a frequency larger than the superconducting gap in the collisionless regime. We show by numerical and analytical computations that a subset of quasiparticle excitations enter into resonance and perform synchronous Rabi oscillations leading to cyclic population inversion with a frequency that depends on the amplitude of the drive. As a consequence a new "Rabi-Higgs" mode emerges. Turning off the drive at different times and modulating the strength allows access to all known dynamical phases of the order parameter: persistent oscillations, oscillations with damping and overdamped dynamics. We discuss physical realizations of the drive and methods to detect the dynamics.

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H. P. Ojeda Collado, José Lorenzana, Gonzalo Usaj, C. A. Balseiro. 2018-08-03. Population inversion and dynamical phase transitions in a driven superconductor. https://doi.org/10.1103/physrevb.98.214519

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