Population inversion and dynamical phase transitions in a driven superconductor

HECTOR PABLO OJEDA COLLADO; JOSÉ LORENZANA; GONZALO USAJ; CARLOS A. BALSEIRO

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2018 vol. 98 p. 214519 - 214519

1098-0121

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 showby 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 onthe 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.