34,915 research outputs found
Effective Action of Matter Fields in Four-Dimensional String Orientifolds
We study various aspects of the Kahler metric for matter fields in N=1,2
orientifold compactifications of type IIB string theory. The result has an
infrared-divergent part which reproduces the field- theoretical anomalous
dimensions, and a moduli-dependent part which comes from N=2 sectors of the
orientifold. For the N=2 orientifolds, we also compute the disk amplitude for
two matter fields on the boundary and a twisted closed string modulus in the
bulk. Our results are in agreement with supersymmetry: the singlet under the
SU(2)_R R-symmetry has vanishing coupling, while the coupling of the SU(2)_R
triplet does not vanish.Comment: 24 pages, JHEP LaTex, no figures, v2: references added, typos
correcte
Heat content with singular initial temperature and singular specific heat
Let (M,g) be a compact Riemannian manifold without boundary. Let D be a
compact subdomain of M with smooth boundary. We examine the heat content
asymptotics for the heat flow from D into M where both the initial temperature
and the specific heat are permitted to have controlled singularities on the
boundary of D. The operator driving the heat process is assumed to be an
operator of Laplace typ
Expected volume of intersection of Wiener sausages and heat kernel norms on compact Riemannian manifolds with boundary
Estimates are obtained for the expected volume of intersection of independent
Wiener sausages in Euclidean space in the small time limit. The asymptotic
behaviour of the weighted diagonal heat kernel norm on compact Riemannian
manifolds with smooth boundary is obtained in the small time limi
String Loop Corrections to Kahler Potentials in Orientifolds
We determine one-loop string corrections to Kahler potentials in type IIB
orientifold compactifications with either N=1 or N=2 supersymmetry, including
D-brane moduli, by evaluating string scattering amplitudes.Comment: 80 pages, 4 figure
The strength of countable saturation
We determine the proof-theoretic strength of the principle of countable
saturation in the context of the systems for nonstandard arithmetic introduced
in our earlier work.Comment: Corrected typos in Lemma 3.4 and the final paragraph of the
conclusio
An efficient, multiple range random walk algorithm to calculate the density of states
We present a new Monte Carlo algorithm that produces results of high accuracy
with reduced simulational effort. Independent random walks are performed
(concurrently or serially) in different, restricted ranges of energy, and the
resultant density of states is modified continuously to produce locally flat
histograms. This method permits us to directly access the free energy and
entropy, is independent of temperature, and is efficient for the study of both
1st order and 2nd order phase transitions. It should also be useful for the
study of complex systems with a rough energy landscape.Comment: 4 pages including 4 ps fig
Glauber dynamics of phase transitions: SU(3) lattice gauge theory
Motivated by questions about the QCD deconfining phase transition, we studied
in two previous papers Model A (Glauber) dynamics of 2D and 3D Potts models,
focusing on structure factor evolution under heating (heating in the gauge
theory notation, i.e., cooling of the spin systems). In the present paper we
set for 3D Potts models (Ising and 3-state) the scale of the dynamical effects
by comparing to equilibrium results at first and second order phase transition
temperatures, obtained by re-weighting from a multicanonical ensemble. Our
finding is that the dynamics entirely overwhelms the critical and non-critical
equilibrium effects.
In the second half of the paper we extend our results by investigating the
Glauber dynamics of pure SU(3) lattice gauge on
lattices directly under heating quenches from the confined into the deconfined
regime. The exponential growth factors of the initial response are calculated,
which give Debye screening mass estimates. The quench leads to competing vacuum
domains of distinct triality, which delay equilibration of pure gauge
theory forever, while their role in full QCD remains a subtle question. As in
spin systems we find for pure SU(3) gauge theory a dynamical growth of
structure factors, reaching maxima which scale approximately with the volume of
the system, before settling down to equilibrium. Their influence on various
observables is studied and different lattice sizes are simulated to illustrate
an approach to a finite volume continuum limit. Strong correlations are found
during the dynamical process, but not in the deconfined phase at equilibrium.Comment: 12 pages, 18 figure
- …