Title: Exact master equation for a spin interacting with a spin bath : Non-Markovianity and entropy production
Event Date:
Friday, 5 May 2017 - 3:00pm
Abstract : An exact canonical master equation of the Lindblad form is
derived for a central spin interacting uniformly with a sea of completely
unpolarized spins. The Kraus operators for the dynamical map are also
derived. The non-Markovianity of the dynamics in terms of the divisibility
breaking of the dynamical map and increase of the trace distance fidelity
between quantum states is shown. Moreover, it is observed that the
irreversible entropy production rate is always negative (for a fixed
initial state) whenever the dynamics exhibits non-Markovian behavior. In
continuation with the study of witnessing non-Markovianity, it is shown
that the positive rate of change of the purity of the central qubit is a
faithful indicator of the non-Markovian information back flow. Given the
experimental feasibility of measuring the purity of a quantum state, a
possibility of experimental demonstration of non-Markovianity and the
negative irreversible entropy production rate is addressed. This gives the
present work considerable practical importance for detecting the
non-Markovianity and the negative irreversible entropy production rate.
Venue:
Room 202 (Seminar room), Physics Department
IIT Bombay, Powai, Mumbai