Other Condensed Matter
We study the effects of magneto-elastic coupling on the degenerate ground state of the antiferromagnetic Heisenberg model on regular triangle and tetrahedron clusters of spin-1/2. Both give very similar results. Static distortion lifts the…
The two-component Fermi gas is the simplest fermion system displaying superfluidity, and as such finds applications ranging from the theory of superconductivity to QCD. Ultracold atomic gases provide an exceptionally clean realization of…
Spin-orbit coupling provides a versatile tool to generate and to manipulate the spin degree of freedom in low-dimensional semiconductor structures. The spin Hall effect, where an electrical current drives a transverse spin current and…
In nanocontacts between normal and ferromagnetic metals (N--F) abrupt changes of the order of 1% are detected in differential resistance, dV/dI(V), versus bias voltage, V, on achieving of high current densities, ~10^9 A/cm^2. These features…
Understanding charging mechanisms and charge retention dynamics of nanocrystal memory devices is important in optimization of device design. Capacitance spectroscopy on PECVD grown germanium nanocrystals embedded in a silicon oxide matrix…
We present time integrated and time resolved measurements on single In/As quantum dots (QD) emitting at 1300nm, at 10K, embedded in a planar microcavity. We clearly identify a standard spectroscopic signature from single QDs and compare the…
We report the phase coherent splitting of Bose-Einstein condensates by means of a phase grating produced near the surface of a micro-electronic chip. A lattice potential with a period of $4\mu$m is generated by the superposition of static…
We propose a new measurement scheme for the atom-molecule dark state by using electromagnetically induced transparency (EIT) technique. Based on a density-matrix formalism, we calculate the absorption coefficient numerically. The appearance…
We study the elementary excitations of a transversely confined Bose-Einstein condensate in presence of a weak axial random potential. We determine the localization length (i) in the hydrodynamical low energy regime, for a domain of linear…
We calculate the hydrodynamic solutions for a dilute Bose-Einstein condensate with long-range dipolar interactions in a rotating, elliptical harmonic trap, and analyse their dynamical stability. The static solutions and their regimes of…
We discuss the zero temperature phase diagram of a dilute gas with three fermionic species. We make use of solvable limits to conjecture the behavior of the system in the "unitary" regions. The physics of the Thomas-Efimov effect plays a…
Resonant activation and noise-enhanced stability were observed in an underdamped real physical system, i.e., Josephson tunnel junctions. With a weak sinusoidal driving force applied, the thermal activated escape from a potential well…
We develop a model for ferromagnetic resonance in systems with competing uniaxial and cubic anisotropies. This model applies to (i) magnetic materials with both uniaxial and cubic anisotropies, and (ii) magnetic nanoparticles with effective…
We model the off-resonant superradiant Raman scattering of light from a cigar-shaped atomic Bose-Einstein condensate. Absorption images of transmitted light serve as a direct probe of long range coherence in the condensate. Our multimode…
We describe a model-independent approach for the extraction of spin-wave dispersion curves from neutron total scattering data. The method utilises a statistical analysis of real-space spin configurations to calculate spin-dynamical…
We investigate a real scalar field whose dynamics is governed by a nonlinear wave equation. We show that classical description can be applied to a quantum system of many interacting bosons provided that some quantum ingredients are…
Dilute gas Bose-Einstein condensates (BEC's), currently used to cool fermionic atoms in atom traps, can also probe the superfluidity of these fermions. The damping rate of BEC-acoustic excitations (phonon modes), measured in the middle of…
We predict new generic types of vorticity-carrying soliton complexes in a class of physical systems including an attractive Bose-Einstein condensate in a square optical lattice (OL) and photonic lattices in photorefractive media. The…
We report on the observation of interference of a series of atom lasers. A comb-like array of coherent atomic beams is generated by outcoupling atoms from distinct Bose-Einstein condensates confined in the independent sites of a mesoscopic…
We discuss ultra-cold Fermi gases in two dimensions, which could be realized in a strongly confining one-dimensional optical lattice. We obtain the temperature versus effective interaction phase diagram for an s-wave superfluid and show…