Geometric Phase for Fermionic Quasiparticles Scattering by Disgyration in Superfluids

We consider a Volovik's analog model for description of a topological defects in a superfluid and we investigate the scattering of quasiparticles in this background. The analog of the gravitational Aharonov-Bohm in this system is found. An analysis of this problem employing loop variables is considered and corroborates for the existence of the Aharonov-Bohm effect in this system. The results presented here may be used to study the Aharonov-Bohm effect in superconductors.Comment: 7 pages, to appear in Europhys. Let

Improved semiclassical density matrix: taming caustics

We present a simple method to deal with caustics in the semiclassical approximation to the thermal density matrix of a particle moving on the line. For simplicity, only its diagonal elements are considered. The only ingredient we require is the knowledge of the extrema of the Euclidean action. The procedure makes use of complex trajectories, and is applied to the quartic double-well potential.Comment: 20 pages, 7 figures. Revised version, accepted for publication in Phys. Rev.

Presença de cinco rainhas fisogástricas em colônia de abelha sem ferrão (Melipona scutellaris Latreille).

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