0302192v2

related topics
{classical, space, random}
{time, wave, function}
{equation, function, exp}
{time, decoherence, evolution}
{state, phys, rev}
{state, algorithm, problem}

Semiclassical evaluation of quantum fidelity

Jiri Vanicek, Eric J. Heller

abstract: We present a numerically feasible semiclassical (SC) method to evaluate quantum fidelity decay (Loschmidt echo, FD) in a classically chaotic system. It was thought that such evaluation would be intractable, but instead we show that a uniform SC expression not only is tractable but it gives remarkably accurate numerical results for the standard map in both the Fermi-golden-rule and Lyapunov regimes. Because it allows Monte Carlo evaluation, the uniform expression is accurate at times when there are 10^70 semiclassical contributions. Remarkably, it also explicitly contains the ``building blocks'' of analytical theories of recent literature, and thus permits a direct test of the approximations made by other authors in these regimes, rather than an a posteriori comparison with numerical results. We explain in more detail the extended validity of the classical perturbation approximation (CPA) and show that within this approximation, the so-called ``diagonal approximation'' is automatic and does not require ensemble averaging.

oai_identifier:
oai:arXiv.org:quant-ph/0302192
categories:
quant-ph nlin.CD
comments:
Added references, small textual improvements
doi:
10.1103/PhysRevE.68.056208
arxiv_id:
quant-ph/0302192
journal_ref:
Phys. Rev. E 68, 056208 (2003).
created:
2003-02-26
updated:
2003-09-17

Full article ▸

related documents
0609112v2
0401142v2
0509141v2
0108054v1
0309192v1
0102032v1
0112100v1
0406039v2
0602007v1
0109076v1
0407128v1
0311009v1
9706014v1
0607131v1
0508057v2
0302169v1
0308164v2
0511108v2
0410103v2
0206103v5
0401103v1
0703200v3
0003005v1
0307119v1
9902006v1