195,197 research outputs found
Consistent boundary conditions for supergravity
We derive the complete orbit of boundary conditions for supergravity models
which is closed under the action of all local symmetries of these models, and
which eliminates spurious field equations on the boundary. We show that the
Gibbons-Hawking boundary conditions break local supersymmetry if one imposes
local boundary conditions on all fields. Nonlocal boundary conditions are not
ruled out. We extend our analysis to BRST symmetry and to the Hamiltonian
formulation of these models.Comment: 37 pages, v2: references added, v3: misprint correcte
Boundary Terms in Supergravity and Supersymmetry
We begin with the simplest possible introduction to supergravity. Then we
discuss its spin 3/2 stress tensor; these results are new. Next, we discuss
boundary conditions on fields and boundary actions for N=1 supergravity.
Finally, we discuss new boundary contributions to the mass and central charge
of monopoles in N=4 super Yang-Mills theory. All models are in 3+1 dimensions.Comment: 15 pages. Talk given by P. van Nieuwenhuizen at the
Einstein-celebration gravitational conference at Puri (India) in December
200
Charges and fields in a current-carrying wire
Charges and fields in a straight, infinite, cylindrical wire carrying a
steady current are determined in the rest frames of ions and electrons,
starting from the standard assumption that the net charge per unit length is
zero in the lattice frame and taking into account a self-induced pinch effect.
The analysis presented illustrates the mutual consistency of classical
electromagnetism and Special Relativity. Some consequences of the assumption
that the net charge per unit length is zero in the electrons frame are also
briefly discussed
The Search for a Realistic String Model at LHC
We survey the low-energy supersymmetry phenomenology of a three-family
Pati-Salam model constructed from intersecting D6-branes in Type IIA string
theory on the T^6/(Z_2 x Z_2) orientifold which possesses many of the
phenomenological properties desired in string model-building. In the model,
there is no exotic matter in the low-energy spectrum, the correct mass
hierarchies for quarks and leptons may be obtained, and the gauge couplings are
automatically unified at the string scale. We calculate the supersymmetry
breaking soft terms and the corresponding low-energy supersymmetry particle
spectra for the model. We find the WMAP constrained dark matter density can be
generated in this model in the stau-neutralino and chargino-neutralino
coannihilation regions, with expected final states at LHC consisting of low
energy leptons and O(GeV) neutrinos. Moreover, we expect final states in the
supercritical string cosmology (SSC) scenario to comprise high energy leptons
and O(GeV) neutrinos.Comment: 35 pages, 4 figures, accepted for publication in PR
Distribution of averages in a correlated Gaussian medium as a tool for the estimation of the cluster distribution on size
Calculation of the distribution of the average value of a Gaussian random
field in a finite domain is carried out for different cases. The results of the
calculation demonstrate a strong dependence of the width of the distribution on
the spatial correlations of the field. Comparison with the simulation results
for the distribution of the size of the cluster indicates that the distribution
of an average field could serve as a useful tool for the estimation of the
asymptotic behavior of the distribution of the size of the clusters for "deep"
clusters where value of the field on each site is much greater than the rms
disorder.Comment: 15 pages, 6 figures, RevTe
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