18,236 research outputs found
Atomic Josephson vortex
We show that Josephson vortices in a quasi-1D atomic Bose Josephson junction
can be controllably manipulated by imposing a difference of chemical potentials
on the atomic BEC waveguides forming the junction. This effect, which has its
origin in the Berry phase structure of a vortex, turns out to be very robust in
the whole range of the parameters where such vortices can exist. We also
propose that a Josephson vortex can be created by the phase imprinting
technique and can be identified by a specific tangential feature in the
interference picture produced by expanding clouds released from the waveguides.Comment: 7 pages, 3 figures, revtex4, submitted to Phys. Rev. A, title and
abstract changed, old sections revised, new sections added, references adde
Macroscopic Quantum Tunneling and the "cosmic" Josephson effect
We discuss the possible influence of a cosmic magnetic field on the
macroscopic quantum tunneling process associated, in a cosmological context, to
the decay of the "false vacuum." We find a close analogy with the effects of an
external magnetic field applied to a Josephson junction in the context of
low-temperature/high-temperature superconducting devices.Comment: 4 pages, 1 pdf figure. Added references and an inset in Fig. 1,
results unchanged. To appear in Phys. Rev. D (Brief Report
Path Integral and the Induction Law
We show how the induction law is correctly used in the path integral
computation of the free particle propagator. The way this primary path integral
example is treated in most textbooks is a little bit missleading.Comment: 5 latex pages, no figure
Observation of a New Fluxon Resonant Mechanism in Annular Josephson Tunnel Structures
A novel dynamical state has been observed in the dynamics of a perdurbed
sine-Gordon system. This resonant state, has been experimentally observed as a
singularity in the dc current voltage characteristic of an annular Josephson
tunnel junction, excited in the presence of a magnetic field. With this
respect, it can be assimilated to self-resonances known as Fiske steps.
Differently from these, however, we demonstrate, on the basis of numerical
simulations, that its detailed dynamics involves rotating fluxon pairs, a
mechanism associated, so far, to self-resonances known as zero-field steps.Comment: 4 pages, 2 figures, submitted to Physical Review Letter
Non-Standard Time Reversal for Particle Multiplets and the Spin-Flavor Structure of Hadrons
We show that a system of quarks interacting with chiral fields provides a
physical representation of a ``non-standard'' time reversal for particle
multiplets proposed by Weinberg. As an application, we argue that, if the
internal structure of hadrons is described by a chiral lagrangian, the
so-called time-reversal-odd quark distribution functions might not be forbidden
by time-reversal invariance.Comment: 2 pages, proceedings of "The Spin Structure of the Proton", ECT -
Trento, July 2001. Eds. S Bass, A De Roeck and A Deshpand
Double transverse-spin asymmetries in Drell--Yan and production from proton--antiproton collisions
We perform a NLO numerical study of the double transverse-spin asymmetries in
the resonance region for proton--antiproton collisions. We analyze the
large kinematic region, relevant for the proposed PAX experiment at GSI,
and discuss the implication of the results for the extraction of the
transversity densities.Comment: 8 pages, 6 figures, Talk given at "Transversity 2005" Como, Italy
7-10 Sep. 2005; eds. World Scientific in pres
- …