G. Lozano

Extended superconformal Galilean symmetry in Chern-Simons matter systems

Abstract We study the nonrelativistic limit of the N = 2 supersymmetric Chern-Simons matter system. We show that in addition to Galilean invariance the model admits a set of symmetries generated by fermionic charges, which can be interpreted as an extended Galilean supersymmetry. The system also possesses a hidden conformal invariance and then the full group of symmetries is the extended superconformal Galilean group. We also show that imposing extended superconformal Galilean symmetry determines the values of the coupling constants in such a way that their values in the bosonic sector agree with the values of Jackiw and Pi for which self-dual equation exist. We finally analyze the second quantized version of the model and the two-particle sector.

Aharonov-Bohm scattering, contact interactions and scale invariance

Abstract We perform a perturbative analysis of the Aharonov-Bohm problem to one loop in a field-theoretic formulation and show that contact interactions are necessary for renormalizability. In general, the classical scale invariance of this problem is broken quantum mechanically. There exists, however, a critical point for which this anomaly disappears.

Self-dual Chern-Simons solitons in noncommutative space

We construct exact soliton solutions to the Chern-Simons-Higgs system in non-commutative space, for non-relativistic and relativistic models. In both cases we find regular vortex-like solutions to the BPS equations which approach the ordinary selfdual non-topological and topological solitons when he non-commutative parameter θ goes to zero.

REAL-TIME NONEQUILIBRIUM DYNAMICS OF QUANTUM GLASSY SYSTEMS

We develop a systematic analytic approach to aging effects in quantum disordered systems in contact with an environment. Within the closed-time path-integral formalism we include dissipation by coupling the system to a set of independent harmonic oscillators that mimic a quantum thermal bath. After integrating over the bath variables and averaging over disorder we obtain an effective action that determines the real-time dynamics of the system. The classical limit yields the Martin-Siggia-Rose generating functional associated to a colored noise. We apply this general formalism to a prototype model related to the p spin glass. We show that the model has a dynamic phase transition separating the paramagnetic from the spin-glass phase and that quantum fluctuations depress the transition temperature until a quantum critical point is reached. We show that the dynamics in the paramagnetic phase is stationary but presents an interesting crossover from a region controlled by the classical critical point to another one controlled by the quantum critical point. The most characteristic property of the dynamics in a glassy phase, namely, aging, survives the quantum fluctuations. In the subcritical region the quantum fluctuation-dissipation theorem is modified in a way that is consistent with the notion of effective temperatures introduced for the classical case. We discuss these results in connection with recent experiments in dipolar quantum spin glasses and the relevance of the effective temperatures with respect to the understanding of the low-temperature dynamics.

On symmetry non-restoration at high temperature

Abstract We study the effect of next-to-leading order contributions on the phenomenon of symmetry non-restoration at high temperature in an O ( N 1 ) × O ( N 2 ) model.We study the effect of next-to-leading order contributions on the phenomenon of symmetry non-restoration at high temperature in an

Quantum Aging in Mean-Field Models

O(N_1)\times O(N_2)

Magnetization dynamics: path-integral formalism for the stochastic Landau–Lifshitz–Gilbert equation

model.

Dissipative effects on quantum glassy systems

We study the real-time dynamics of quantum models with long-range interactions coupled to a heat-bath within the closed-time path-integral formalism. We show that quantum fluctuations depress the transition temperature. In the subcritical region there are two asymptotic time-regimes with (i) stationary, and (ii) slow aging dynamics. We extend the quantum fluctuation-dissipation theorem to the nonequilibrium case in a consistent way with the notion of an effective temperature that drives the system in the aging regime. The classical results are recovered for

Current-induced switching in transport through anisotropic magnetic molecules

\hbar\to 0

Ordered, disordered, and coexistent stable vortex lattices in NbSe2 single crystals.

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