arXiv subjects

M. Barranco

Publications and source records attributed to M. Barranco.

40 records · Page 3Linked to original sources

arXiv1997

Far-infrared edge modes in quantum dots

We have investigated edge modes of different multipolarity sustained by quantum dots submitted to external magnetic fields. We present a microscopic description based on a variational solution of the equation of motion for any axially symmetric confining potential and multipole mode. Numerical results for dots with different number of electrons whose ground-state is described within a local Current Density Functional Theory are discussed. Two sum rules, which are exact within this theory, are derived. In the limit of a large neutral dot at B=0, we have shown that the classical hydrodynamic dispersion law for edge waves ω(q) \sim \sqrt{q \ln (q_0/q)} holds when quantum and finite size effects are taken into account.

cond-mat↗

arXiv1996

Stability of vortex lines in liquid 3He-4He mixtures at zero temperature

At low temperatures and 3He concentrations below 6.6 %, there is experimental evidence about the existence in liquid helium mixtures, of stable vortices with 3He-rich cores. When the system is either supersaturated or submitted to a tensile strength, vortices lose stability becoming metastable and eventually completely unstable, so that their cores freely expand. Within a density functional approach, we have determined the pressure-3He concentration curve along which this instability appears at zero temperature.

cond-mat↗

arXiv1996

Quantum cavitation in liquid helium

Using a functional-integral approach, we have determined the temperature below which cavitation in liquid helium is driven by thermally assisted quantum tunneling. For both helium isotopes, we have obtained the crossover temperature in the whole range of allowed negative p essures. Our results are compatible with recent experimental results on 4He.

cond-mat↗

arXiv1996

Thermally assisted quantum cavitation in solutions of 3He in 4He

We have investigated the quantum-to-thermal crossover temperature T* for cavitation in liquid helium mixtures up to 0.05 3He concentrations. With respect to the pure 4He case, T* is sizeably reduced, to a value below 50 mK for 3He concentrations above 0.02. As in pure 4He, the homogeneous cavitation pressure is systematically found close to the spinodal pressure.

cond-mat↗