Comment on 'Quantum inversion of cold atoms in a microcavity: spatial dependence'

In a recent work, Abdel-Aty and Obada [2002 J. Phys. B 35 807-813] analyzed the quantum inversion of cold atoms in a microcavity, the motion of the atoms being described quantum mechanically. Two-level atoms were assumed to interact with a single mode of the cavity, and the off-resonance case was considered (namely the atomic transition frequency is detuned from the single mode cavity frequency). We demonstrate in this paper that this case is incorrectly treated by these authors and we question therefore their conclusions.Comment: 4 pages, no figure

Tsallis' deformation parameter q quantifies the classical-quantum transition

We investigate the classical limit of a type of semiclassical evolution, the pertinent system representing the interaction between matter and a given field. On using as a quantifier of the ensuing dynamics Tsallis q-entropy, we encounter that it not only appropriately describes the quantum-classical transition, but that the associated deformation-parameter q itself characterizes the different regimes involved in the process, detecting the most salient fine details of the changeover.Comment: 19 pages, 7 figure

Experimental constraints on the polarizabilities of the 6s^2 1S0 and 6s6p 3P0 states of Yb

We utilize accurate experimental data available in the literature to yield bounds on the polarizabilities of the ground and first excited states of atomic Yb. For the 6s^2 1S0 ground state, we find the polarizability alpha to be constrained to 134.4<alpha<144.2 in atomic units, while for the 6s6p 3P0 excited state we find 280.1<alpha<289.9. The uncertainty in each of these values is 1.0. These constraints provide a valuable check for ab initio and semi-empirical methods used to compute polarizabilities and other related properties in Yb.Comment: 7 pages, 1 figur

An electronic Mach-Zehnder interferometer in the Fractional Quantum Hall effect

We compute the interference pattern of a Mach-Zehnder interferometer operating in the fractional quantum Hall effect. Our theoretical proposal is inspired by a remarkable experiment on edge states in the Integer Quantum Hall effect (IQHE). The Luttinger liquid model is solved via two independent methods: refermionization at nu=1/2 and the Bethe Ansatz solution available for Laughlin fractions. The current differs strongly from that of single electrons in the strong backscattering regime. The Fano factor is periodic in the flux, and it exhibits a sharp transition from sub-Poissonian (charge e/2) to Poissonian (charge e) in the neighborhood of destructive interferences