English

Dissipation and Decoherence in a Quantum Register

Quantum Physics 2011-07-19 v2

Abstract

A model for a quantum register R\cal R made of NN replicas of a dd-dimensional quantum system (cell) coupled with the environment, is studied by means of a Born-Markov Master Equation (ME). Dissipation and decoherence are discussed in various cases in which a sub-decoherent enconding can be rigorously found. For the qubit case (d=2d=2) we have solved, for small N,N, the ME by numerical direct integration and studied, as a function of the coherence length ξc\xi_c of the bath, fidelity and decoherence rates of states of the register. For large enough ξc\xi_c the singlet states of the global su(2)su(2) pseudo-spin algebra of the register (noiseless at ξc=\xi_c=\infty) are shown to have a much smaller decoherence rates than the rest of the Hilbert space.

Keywords

Cite

@article{arxiv.quant-ph/9705045,
  title  = {Dissipation and Decoherence in a Quantum Register},
  author = {Paolo Zanardi},
  journal= {arXiv preprint arXiv:quant-ph/9705045},
  year   = {2011}
}

Comments

minor corrections, references added, to appear in PRA (10 pages + 5 figures LaTeX)