Non-Markovian decoherence of a two-level system weakly coupled to a bosonic bath
Artikel i vetenskaplig tidskrift, 2011

The Bloch-Redfield equation is a common tool for studying the evolution of qubit systems weakly coupled to the environment. We investigate the accuracy of the Born approximation underlying this equation. We find that the high-order terms in the perturbative expansion contain accumulating divergences that make straightforward Born approximation inappropriate. We develop a diagrammatic technique to formulate, and solve the improved self-consistent Born approximation. This more accurate treatment reveals an exponential timedependent prefactor in the non-Markovian contribution dominating the qubit long-time relaxation found in Di Vincenzo D. P. and Loss D., Phys. Rev. B, 71 (2005) 035318. At the same time, the associated dephasing is not affected and is described by the Born-Markov approximation.

Författare

A.A. Slutskin

B Verkin Institute for Low Temperature Physics and Engineering Nasu

K.N. Bratus'

B Verkin Institute for Low Temperature Physics and Engineering Nasu

Anders Bergvall

Chalmers, Mikroteknologi och nanovetenskap (MC2), Tillämpad kvantfysik

Vitaly Shumeiko

Chalmers, Mikroteknologi och nanovetenskap (MC2), Tillämpad kvantfysik

Europhysics Letters

0295-5075 (ISSN) 1286-4854 (eISSN)

Vol. 96 4003-

Styrkeområden

Nanovetenskap och nanoteknik

Ämneskategorier

Annan fysik

Den kondenserade materiens fysik

DOI

10.1209/0295-5075/96/40003