19,878 research outputs found
Non-equilibrium phonon dynamics in trapped ion systems
We propose a concrete experiment to probe the non-equilibrium local dynamics
of the one-dimensional Bose-Hubbard model using a trapped ion system consisting
of a linear chain of few Ba^+ ions prepared in a state of transverse motional
mode which corresponds to a fixed number of phonons per ion. These phonons are
well-known to be described by an effective Bose-Hubbard model. We propose a
protocol which leads to a sudden local sign reversal of the on-site interaction
strength of this Hubbard model at one of the sites and demonstrate that the
subsequent non-equilibrium dynamics of the model can be experimentally probed
by measuring the time-dependent phonon number in a specific motional state of
the Ba+ ions. We back our experimental proposal with exact numerical
calculation of the dynamics of a Bose-Hubbard model subsequent to a local
quench.Comment: The submission contains 5 pages and 4 figure
Parity Nonconservation in Odd-isotopes of Single Trapped Atomic Ions
We have estimated the size of the light-shifts due to parity nonconservation
(PNC) interactions in different isotopes of Ba+ and Ra+ ions based on the work
of Fortson [Phys. Rev. Lett. 70, 2383 (1993)]. We have used the nuclear spin
independent (NSI) amplitudes calculated earlier by us [Phys. Rev. Lett. 96,
163003 (2006); Phys. Rev. A 78, 050501(R) (2008)] and we have employed the
third order many-body perturbation theory (MBPT(3)) in this work to estimate
the nuclear spin dependent (NSD) amplitudes in these ions. Ra+ is found to be
more favourable than Ba+ for measuring both the NSI and NSD PNC observables.Comment: 5 pages, 1 tabl
Classical linear chain behavior from dipolar droplets to supersolids
We investigate the classicality of linear dipolar droplet arrays through a
normal mode analysis of the dynamical properties in comparison to the
supersolid regime. The vibrational patterns of isolated-droplet crystals that
time-evolve after a small initial kick closely follow the properties of a
linear droplet chain. For larger kick velocities, however, droplets may
coalesce and separate again, showing distinct deviations from classicality. In
the supersolid regime the normal modes are eliminated by a counter-flow of mass
between the droplets, signaled by a reduction of the center-of-mass motion
A Note on the Picard-Fuchs Equations for N=2 Seiberg-Witten Theories
A concise presentation of the PF equations for N=2 Seiberg-Witten theories
for the classical groups of rank r with N_f massless hypermultiplets in the
fundamental representation is provided. For N_f=0, all r PF equations can be
given in a generic form. For certain cases with N_f\neq zero, not all equations
are generic. However, in all cases there are at least r-2 generic PF equations.
For these cases the classical part of the equations is generic, while the
quantum part can be formulated using a method described in a previous paper by
the authors, which is well suited to symbolic computer calculations.Comment: 25 pages, Latex; some new references adde
Fidelity susceptibility and general quench near an anisotropic quantum critical point
We study the scaling behavior of fidelity susceptibility density at or close to an anisotropic quantum critical point characterized by two
different correlation length exponents and along
parallel and perpendicular spatial directions, respectively. Our studies show
that the response of the system due to a small change in the Hamiltonian near
an anisotropic quantum critical point is different from that seen near an
isotropic quantum critical point. In particular, for a finite system with
linear dimension () in the parallel (perpendicular)
directions, the maximum value of is found to increases in a
power-law fashion with for small , with an exponent depending
on both and and eventually crosses over to a scaling
with for . We
also propose scaling relations of heat density and defect density generated
following a quench starting from an anisotropic quantum critical point and
connect them to a generalized fidelity susceptibility. These predictions are
verified exactly both analytically and numerically taking the example of a
Hamiltonian showing a semi-Dirac band-crossing point.Comment: 6 pages, 6 pigure
Accessing the Longitudinally Polarized Photon Content of the Proton
We investigate the QED Compton process (QEDCS) in longitudinally polarized
lepton-proton scattering both in the elastic and inelastic channels and show
that the cross section can be expressed in terms of the polarized equivalent
photon distribution of the proton. We provide the necessary kinematical
constraints to extract the polarized photon content of the proton using this
process at HERMES, COMPASS and eRHIC. We also discuss the suppression of the
major background process coming from virtual Compton scattering. We point out
that such an experiment can give valuable information on in the
small , broad region at the future polarized collider eRHIC and
especially in the lower , medium region in fixed target experiments.Comment: Version to appear in PR
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