15,768 research outputs found
Feasibility of a storage ring for polar molecules in strong-field-seeking states
We show, through modeling and simulation, that it is feasible to construct a
storage ring that will store dense bunches of strong-field-seeking polar
molecules at 30 m/s (kinetic energy of 2K) and hold them, for several minutes,
against losses due to defocusing, oscillations, and diffusion. The ring, 3 m in
diameter, has straight sections that afford access to the stored molecules and
a lattice structure that may be adapted for evaporative cooling. Simulation is
done using a newly-developed code that tracks the particles, in time, through
400 turns; it accounts for longitudinal velocity changes as a function of
external electric field, focusing and deflection nonlinearities, and the
effects of gravity. An injector, decelerator, and source are included and
intensities are calculated.Comment: 6 pages 5 figures, 3 table
Dynamical generation of gauge groups in the massive Yang-Mills-Chern-Simons matrix model
It has been known for some time that the dynamics of k coincident D-branes in
string theory is described effectively by U(k) Yang-Mills theory at low energy.
While these configurations appear as classical solutions in matrix models, it
was not clear whether it is possible to realize the k =/= 1 case as the true
vacuum. The massive Yang-Mills-Chern-Simons matrix model has classical
solutions corresponding to all the representations of the SU(2) algebra, and
provides an opportunity to address the above issue on a firm ground. We
investigate the phase structure of the model, and find in particular that there
exists a parameter region where O(N) copies of the spin-1/2 representation
appear as the true vacuum, thus realizing a nontrivial gauge group dynamically.
Such configurations are analogous to the ones that are interpreted in the BMN
matrix model as coinciding transverse 5-branes in M-theory.Comment: 4 pages, 3 figures, (v3) some typos correcte
Systematic study of the SO(10) symmetry breaking vacua in the matrix model for type IIB superstrings
We study the properties of the space-time that emerges dynamically from the
matrix model for type IIB superstrings in ten dimensions. We calculate the free
energy and the extent of space-time using the Gaussian expansion method up to
the third order. Unlike previous works, we study the SO(d) symmetric vacua with
all possible values of d within the range , and observe clear
indication of plateaus in the parameter space of the Gaussian action, which is
crucial for the results to be reliable. The obtained results indeed exhibit
systematic dependence on d, which turns out to be surprisingly similar to what
was observed recently in an analogous work on the six-dimensional version of
the model. In particular, we find the following properties: i) the extent in
the shrunken directions is given by a constant, which does not depend on d; ii)
the ten-dimensional volume of the Euclidean space-time is given by a constant,
which does not depend on d except for d = 2; iii) The free energy takes the
minimum value at d = 3. Intuitive understanding of these results is given by
using the low-energy effective theory and some Monte Carlo results.Comment: 33 pages, 10 figures; minor corrections, reference added. arXiv admin
note: substantial text overlap with arXiv:1007.088
Convergence of the Gaussian Expansion Method in Dimensionally Reduced Yang-Mills Integrals
We advocate a method to improve systematically the self-consistent harmonic
approximation (or the Gaussian approximation), which has been employed
extensively in condensed matter physics and statistical mechanics. We
demonstrate the {\em convergence} of the method in a model obtained from
dimensional reduction of SU() Yang-Mills theory in dimensions. Explicit
calculations have been carried out up to the 7th order in the large-N limit,
and we do observe a clear convergence to Monte Carlo results. For the convergence is already achieved at the 3rd order, which suggests that
the method is particularly useful for studying the IIB matrix model, a
conjectured nonperturbative definition of type IIB superstring theory.Comment: LaTeX, 4 pages, 5 figures; title slightly changed, explanations added
(16 pages, 14 figures), final version published in JHE
Numerical Study of TAP Metastable States in 3-body Ising Spin Glasses
The distribution of solutions of the Thouless-Anderson-Palmer equation is
studied by extensive numerical experiments for fully connected 3-body
interaction Ising spin glass models in a level of annealed calculation. A
recent study predicted that when the equilibrium state of the system is
characterized by one-step replica symmetry breaking, the distribution is
described by a Becchi-Rouet-Stora-Tyutin (BRST) supersymmetric solution in the
relatively low free energy region, whereas the BRST supersymmetry is broken for
higher values of free energy (Crisanti et al., Phys. Rev. B 71 (2005) 094202).
Our experiments qualitatively reproduce the discriminative behavior of
macroscopic variables predicted by the theoretical assessment.Comment: 13 pages, 4 figure
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