Usually, as it is general wisdom, quantum fluctuations enhance the escape from a quantum dissipative metastable state. A critical issue is whether the dissipation and/or an external driving force can enhance the stability of quantum metastable states. We show here that dissipation can enhance the stability of a quantum metastable system strongly interacting with a thermal bath. We find that the escape time from the metastable region, with unstable initial condition, has a nonmonotonic behavior versus the system-bath coupling and the temperature, producing a stabilizing effect. Moreover, the combined effects of strong Ohmic dissipation and monochromatic driving affect the stability of a quantum system with a metastable state. 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 system investigated. Moreover, by investigating the resonantly activated escape from a quantum metastable state by tunneling in the spin-boson model at strong Ohmic dissipation in the presence of fluctuating driving fields, the stochastic resonant activation phenomenon is observed. These results shed new light on the role of the environmental fluctuations in stabilizing quantum metastable systems, to control the escape dynamics to engineer dissipative environments, and exploit dissipation induced steady states for quantum computation.

The work is supported by the Grant of the Government of the Russian Federation (contract No.074-02-2018-330 (2))

References

D. Valenti, A. Carollo, B. Spagnolo, “Stabilizing effect of driving and dissipation on quantum metastable states”, Physical Review A 97, 042109 (2018).