16,110 research outputs found
High-harmonic generation from arbitrarily oriented diatomic molecules including nuclear motion and field-free alignment
We present a theoretical model of high-harmonic generation from diatomic
molecules. The theory includes effects of alignment as well as nuclear motion
and is used to predict results for N, O, H and D. The results
show that the alignment dependence of high-harmonics is governed by the
symmetry of the highest occupied molecular orbital and that the inclusion of
the nuclear motion in the theoretical description generally reduces the
intensity of the harmonic radiation. We compare our model with experimental
results on N and O, and obtain very good agreement.Comment: 12 pages, 8 figures, 2 tables; legends revised on Figs. 1,3,4,6 and
Spin squeezing and precision probing with light and samples of atoms in the gaussian approximation
We consider an ensemble of trapped atoms interacting with a continuous wave
laser field. For sufficiently polarized atoms and for a polarized light field,
we may approximate the non-classical components of the collective spin angular
momentum operator for the atoms and the Stokes vectors of the field by
effective position and momentum variables for which we assume a gaussian state.
Within this approximation, we present a theory for the squeezing of the atomic
spin by polarization rotation measurements on the probe light. We derive
analytical expressions for the squeezing with and without inclusion of the
noise effects introduced by atomic decay and by photon absorption. The theory
is readily adapted to the case of inhomogeneous light-atom coupling [A. Kuzmich
and T.A.B. Kennedy, Phys. Rev. Lett. Vol. 92, 030407 (2004)]. As a special
case, we show how to formulate the theory for an optically thick sample by
slicing the gas into pieces each having only small photon absorption
probability. Our analysis of a realistic probing and measurement scheme shows
that it is the maximally squeezed component of the atomic gas that determines
the accuracy of the measurement.Comment: 12 pages, 5 figure
Chemical Evolution of Strongly Magnetized Quark Core in a Newborn Neutron Star
The chemical evolution of nascent quark matter core in a newborn compact
neutron star is studied in presence of a strong magnetic field. The effective
rate of strange quark production in degenerate quark matter core in presence of
strong magnetic fields is obtained. The investigations show that in presence of
strong magnetic fields a quark matter core becomes energetically unstable and
hence a deconfinement transition to quark matter at the centre of a compact
neutron star under such circumstances is not possible. The critical strength of
magnetic field at the central core to make the system energetically unstable
with respect to dense nuclear matter is found to be G.
This is the typical strength at which the Landau levels for electrons are
populated. The other possible phase transitions at such high density and ultra
strong magnetic field environment are discussed.Comment: 18 pages, latex, eight EPS figures not included, available under
request, REVTEX forma
Charge and critical density of strange quark matter
The electric charge of strange quark matter is of vital importance to
experiments. A recent investigation shows that strangelets are most likely
highly negatively charged, rather than slightly positively charged as
previously believed. Our present study indicates that negative charges can
indeed lower the critical density, and thus be favorable to the experimental
searches in heavy ion collisions. However, too much negative charges can make
it impossible to maintain flavor equilibrium.Comment: 4 pages, LATeX with REVTeX style, one PS figure. To be published in
Phys. Rev. C 59(6), 199
High Q Cavity Induced Fluxon Bunching in Inductively Coupled Josephson Junctions
We consider fluxon dynamics in a stack of inductively coupled long Josephson
junctions connected capacitively to a common resonant cavity at one of the
boundaries. We study, through theoretical and numerical analysis, the
possibility for the cavity to induce a transition from the energetically
favored state of spatially separated shuttling fluxons in the different
junctions to a high velocity, high energy state of identical fluxon modes.Comment: 8 pages, 5 figure
- …