Metastable states in strongly coupled quantum systems with continuous spectra

Mark Makela, Samantha Parmley, Roger Yu

Sharareh Sayyad, Martin Eckstein

Using a nonequilibrium dynamical mean-field theory the authors study relaxation of a hot-electron distribution coupled to optical phonons. Their main interest is in the adiabatic regime of phonon frequencies smaller than the electronic bandwidth and in an extended analysis of photoemission spectra. In this limit initial coherent phonon oscillations become strongly damped, leaving the system in a mixture of excited polaron states and metastable delocalized states.

Davide Valenti, Luca Magazzù, Pasquale Caldara +1 more

Normally, quantum fluctuations enhance the escape from metastable states in the presence of dissipation. Here we show that dissipation can enhance the stability of a quantum metastable system, consisting of a particle moving in a strongly asymmetric double well potential, interacting with a thermal bath. We find that the escape time from the metastable region has a nonmonotonic behavior versus the system-bath coupling and the temperature, producing a stabilizing effect.

Bala Sundaram

Davide Valenti, Angelo C. M. Carollo, Bernardo Spagnolo

We investigate how the combined effects of strong Ohmic dissipation and monochromatic driving affect the stability of a quantum system with a metastable state. We find that, by increasing the coupling with the environment, the escape time makes a transition from a regime in which it is substantially controlled by the driving, displaying resonant peaks and dips, to a regime of frequency-independent escape time with a peak followed by a steep falloff. The escape time from the metastable state has a nonmonotonic behavior as a function of the thermal-bath coupling, the temperature, and the frequency of the driving. The quantum noise-enhanced stability phenomenon is observed in the investigated system.

Roberto Cristiano, Luigi Frunzio, Yurii N. Ovchinnikov +1 more