The recently derived distributions for the scattering-matrix elements in quantum chaotic systems are not accessible in the majority of experiments, whereas the cross sections are. We analytically compute distributions for the off-diagonal cross sections in the Heidelberg approach, which is applicable to a wide range of quantum chaotic systems. Thus, eventually, we fully solve a problem that already arose more than half a century ago in compound-nucleus scattering. We compare our results with data from microwave and compound-nucleus experiments, particularly addressing the transition from isolated resonances towards the Ericson regime of strongly overlapping ones. © 2017 American Physical Society.

Santosh Kumar

Physics

(SoNS) School of Natural Sciences

Dietz B.

Guhr T.

Richter A.

Fulltext

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Shiv Nadar University

Physical Review Letters

We investigate the spectral fluctuations and electronic transport properties of chaotic mesoscopic cavities using Kwant, an open source Python programming language based package. Discretized chaotic billiard systems are used to model these mesoscopic cavities. For the spectral fluctuations, we study the ratio of consecutive eigenvalue spacings, and for the transport properties, we focus on Landauer conductance and shot noise power. We generate an ensemble of scattering matrices in Kwant, with desired number of open channels in the leads attached to the cavity. The results obtained from Kwant simulations, performed without or with magnetic field, are compared with the corresponding random matrix theory predictions for orthogonally and unitarily invariant ensembles. These two cases apply to the scenarios of preserved and broken time-reversal symmetry, respectively. In addition, we explore the orthogonal to unitary crossover statistics by varying the magnetic field and examine its relationship with the random matrix transition parameter. © 2020 Author(s).

Chaos

Electronic transport in chaotic mesoscopic cavities: A Kwant and random matrix theory based exploration

Physical Review E

Cross-section fluctuations in chaotic scattering systems

Physical Review C

Statistical Hauser-Feshbach theory with width-fluctuation correction including direct reaction channels for neutron-induced reactions at low energies

Random-matrix approach to the statistical compound nuclear reaction at low energies using the Monte Carlo technique

Chaos: An Interdisciplinary Journal of Nonlinear Science

Quantum and wave dynamical chaos in superconducting microwave billiards

Journal of Statistical Physics

On Random Matrix Averages Involving Half-Integer Powers of GOE Characteristic Polynomials

Distribution of Off-Diagonal Cross Sections in Quantum Chaotic Scattering: Exact Results and Data Comparison