Quantum Institute: Visitor Schedule

The Quantum Lunch is regularly held on Thursdays in the Theoretical Division Conference Room, TA-3, Building 123, Room 121.
For more information, contact Diego Dalvit.

Thursday, June 12, 2008
12:30 PM to 2 PM

Speaker: Marco Merkli, Memorial University

Technical Host: Gennady Berman

TOPIC: Resonance method and decoherence

Abstract
I will explain how one can find the dynamics of the reduced density matrix of an open quantum system subject to energy conserving and energy exchange interactions with a heat bath. The proposed resonance method does not involve any markovian approximation, and is applicable to models which are not explicitly solvable. It is based on a (rigorous) expansion in the coupling strength between the system and the reservoir and holds for all times.

The resonance method allows to calculate the decoherence and relaxation times of matrix elements. I will present explicit results for an N-qubit quantum register. I will also describe how the resonance method applies to systems with time-dependent dynamics ("forced systems"). In particular, I will present formulas for transition probabilities from the ground state to the excited state of a single qubit coupled to the thermal environment, and where the level spacing of the isolated qubit is quite arbitrary (allowing arbitrary level crossings).