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|Title:||Resonance width distribution in RMT: Weak-coupling regime beyond Porter-Thomas|
|Citation:||EPL, 110, (4), (2015)|
|Abstract:||We employ the random matrix theory (RMT) framework to revisit the distribution of resonance widths in quantum chaotic systems weakly coupled to the continuum via a finite number M of open channels. In contrast to the standard first-order perturbation theory treatment we do not a priori assume the resonance widths being small compared to the mean level spacing. We show that to the leading order in weak coupling the perturbative χ<inf>M</inf><sup>2</sup> distribution of the resonance widths (in particular, the Porter-Thomas distribution at M = 1) should be corrected by a factor related to a certain average of the ratio of square roots of the characteristic polynomial ("spectral determinant") of the underlying RMT Hamiltonian. A simple single-channel expression is obtained that properly approximates the width distribution also at large resonance overlap, where the Porter-Thomas result is no longer applicable.|
|Appears in Collections:||Dept of Mathematics Research Papers|
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