Adiabatic Control of the Electron Phase in a Quantum Dot

A Berry phase can be added to the wavefunction of an isolated quantum dot by adiabatically modulating a nonuniform electric field along a time-cycle. The dot is tuned close to a three-level degeneracy, which provides a wide range of possibilities of control. We propose to detect the accumulated phase by capacitively coupling the dot to a double-path inteferometer. The effective Hamiltonian for the phase-sensitive coupling is discussed in detail.Comment: 14 pages, 2 .eps figure

A dual 2D model for the Quantum Hall Fluid

We present a dual two dimensional model for the Quantum Hall Fluid depending on two parameters and show that this model has topologically non-trivial vacua which are infrared stable fixed points of the Renormalization Group. The model has a discrete (modular) symmetry which reproduces the fenomenological law of corresponding states and allows for an unified description of the critical points corresponding to Hall plateaus in terms of a 2 dimensional Conformal Field Theory.Comment: 10 pages, Revtex, no figure

Edge insulating topological phases in a two-dimensional long-range superconductor

We study the zero-temperature phase diagram of a two dimensional square lattice loaded by spinless fermions, with nearest neighbor hopping and algebraically decaying pairing. We find that for sufficiently long-range pairing, new phases, not continuously connected with any short-range phase, occur, signaled by the violation of the area law for the Von Neumann entropy, by semi-integer Chern numbers, and by edge modes with nonzero mass. The latter feature results in the absence of single-fermion edge conductivity, present instead in the short- range limit. The definition of a topology in the bulk and the presence of a bulk-boundary correspondence is still suggested for the long-range phases. Recent experimental proposals and advances open the stimulating possibility to probe the described long-range effects in next-future realistic set-ups

Quantum interference of electrons in a ring: tuning of the geometrical phase

We calculate the oscillations of the DC conductance across a mesoscopic ring, simultaneously tuned by applied magnetic and electric fields orthogonal to the ring. The oscillations depend on the Aharonov-Bohm flux and of the spin-orbit coupling. They result from mixing of the dynamical phase, including the Zeeman spin splitting, and of geometric phases. By changing the applied fields, the geometric phase contribution to the conductance oscillations can be tuned from the adiabatic (Berry) to the nonadiabatic (Ahronov-Anandan) regime. To model a realistic device, we also include nonzero backscattering at the connection between ring and contacts, and a random phase for electron wavefunction, accounting for dephasing due to disorder.Comment: 4 pages, 3 figures, minor change

Investigation of the potentialities of photochemical laser systems. Part I - Survey and analysis Final report, 1 Feb. 1966 - 31 Jan. 1967

Photodissociative laser systems used to convert solar radiation to monochromatic coherent emission - excitation mechanisms, spectroscopy of gases absorbing light, and chemical processe