Stochastic Resonance Phenomena in Quantum Many-Body Systems
  We discuss stochastic resonance (SR) effects in driven coupled quantum systems. We construct dynamical and information theoretic measures of the system's response that exhibit a non-monotonic behaviour as a function of the noise strength. We analyze the relation between lack of monotonicity in the response and the presence of quantum correlations and identify parameter regimes where the breakdown of a linear response can be linked to the presence of entanglement. We also show that a chain of coupled spin systems can exhibit an array-enhanced response, where the sensitivity of a single resonator is enhanced as a result of nearest-neighbour coupling. These results enlarge the domain where SR effects exist and should be observable in arrays of superconducting qubits. 
Susana Huelga (UH) and Martin Plenio (Imperial College London)