Acceleration of material waves in Fermi accelerator.
Anomalously slow cross symmetry phase relaxation, thermalized non-equilibrated matter and quantum computing beyond the quantum chaos border.
Can drag force suppress Fermi acceleration in a bouncer model?
Counting problems and semisimple groups.
Dynamical entropy of a non-commutative version of the phase doubling
A quantum dynamical system, mimicking the classical phase doubling map on the unit circle, is formulated and its ergodic properties are studied. We prove that the quantum dynamical entropy equals the classical value log2 by using compact perturbations of the identity as operational partitions of unity.
Eigenfunctions of the laplacian, quantum chaos, and computation
Entropy and localization of eigenfunctions
Equidistribution of cusp forms on
We prove a microlocal version of the equidistribution theorem for Wigner distributions associated to cusp forms on . This generalizes a recent result of W. Luo and P. Sarnak who prove equidistribution on .
Half-delocalization of eigenfunctions for the Laplacian on an Anosov manifold
We study the high-energy eigenfunctions of the Laplacian on a compact Riemannian manifold with Anosov geodesic flow. The localization of a semiclassical measure associated with a sequence of eigenfunctions is characterized by the Kolmogorov-Sinai entropy of this measure. We show that this entropy is necessarily bounded from below by a constant which, in the case of constant negative curvature, equals half the maximal entropy. In this sense, high-energy eigenfunctions are at least half-delocalized....
Localisation for the spin J-boson hamiltonian
Mécanique quantique sur le tore et dégénérescences dans le spectre
On nodal sets and nodal domains on and
We discuss possible topological configurations of nodal sets, in particular the number of their components, for spherical harmonics on . We also construct a solution of the equation in that has only two nodal domains. This equation arises in the study of high energy eigenfunctions.
On quantum twist maps and spectral properties of Floquet operators
On the dynamical meaning of spectral dimensions
Quantum dynamical entropy and an algorithm by Gene Golub.
Recurrent versus diffusive dynamics for a kicked quantum oscillator
Semi-classical formula beyond the Ehrenfest time in quantum chaos. (I) Trace formula
We consider a nonlinear area preserving Anosov map on the torus phase space, which is the simplest example of a fully chaotic dynamics. We are interested in the quantum dynamics for long time, generated by the unitary quantum propagator . The usual semi-classical Trace formula expresses for finite time , in the limit , in terms of periodic orbits of of period . Recent work reach time where is the Ehrenfest time, and is the Lyapounov coefficient. Using a semi-classical normal form...
Some details of proofs of theorems related to the quantum dynamical Yang-Baxter equation.
Spectra of elements in the group ring of SU(2)
We present a new method for establishing the ‘‘gap” property for finitely generated subgroups of , providing an elementary solution of Ruziewicz problem on as well as giving many new examples of finitely generated subgroups of with an explicit gap. The distribution of the eigenvalues of the elements of the group ring in the -th irreducible representation of is also studied. Numerical experiments indicate that for a generic (in measure) element of , the “unfolded” consecutive spacings...
Spectral statistics.