Quantum Information Processing in Noisy Environments
November 6th, 2019 SREETAMA DAS HRI-Harish Chandra Research Institute, India

I will discuss various quantum informatic aspects when a system is interacting with an environment and the effects of disorder on the system induced by the environment. In another work, we identify a set of dynamical maps of open quantum system, and refer to them as “\epsilon-Markovian” maps. It is constituted of maps that possibly violate Markovianity but only a “little We characterize the “\epsilon- nonmarkovianity” of a general dynamical map by the minimum distance of that map from the set of \epsilon-Markovian maps. We analytically derive an inequality which gives a bound on the \epsilon-nonmarkovianity of the dynamical map, in terms of an entanglement-like resource generated between the system and its “immediate” environment. In the special case of a vanishing \epsilon, this inequality gives a relation between the non-Markovianity of the reduced dynamical map on the system and the entanglement generated between the system and its immediate environment. We show that one can construct a quantum absorption refrigerator that provides refrigeration only in the transient regime, by using three interacting qubits, each of which is also interacting with local heat-bath. The machine either does not provide cooling in the steady state, or the steady state is achieved after a long time. We propose a canonical form of qubit-bath interaction parameters that generates transient cooling without steady-state cooling, and claim that such a phenomenon is generic to small-scale quantum absorption refrigerators. We also show that it is generically possible to have fast cooling.

Seminar, November 6, 2019, 12:00. ICFO’s Seminar Room

Hosted by Prof. Maciej Lewenstein