873 research outputs found
Fundamental Structures of M(brane) Theory
A dynamical symmetry, as well as special diffeomorphism algebras generalizing
the Witt-Virasoro algebra, related to Poincar\'e-invariance and crucial with
regard to quantisation, questions of integrability, and M(atrix) theory, are
found to exist in the theory of relativistic extended objects of any dimension
Lattice-dynamical calculation of phonon scattering at a disordered interface
For an fcc crystal with central force interactions and separately for a
scalar model on a square lattice, we compute exactly the phonon transmission
coefficient through a disordered planar interface between two
identical semi - infinite leads. At high frequencies exhibits a
strong frequency dependence which is determined by the correlation length of
the disorder.Comment: to appear in Physica B, proceedings of the 9th international
conference on phonon scatterin
Dynamic method to distinguish between left- and right-handed chiral molecules
We study quantum systems with broken symmetry that can be modelled as cyclic
three-level atoms with coexisting one- and two-photon transitions. They can be
selectively optically excited to any state. As an example, we show that left-
and right-handed chiral molecules starting in the same initial states can
evolve into different final states by a purely dynamic transfer process. That
means, left- and right-handed molecules can be distinguished purely
dynamically.Comment: 4 pages, submitted to Phys. Rev.
On the absence of localized curvature in the weak-coupling phase of quantum gravity
In the weak field expansion of euclidean quantum gravity, an analysis of the
Wilson loops in terms of the gauge group, , shows that the correspondent
statistical system does not develope any configuration with localized curvature
at low temperature. Such a ``non-local'' behavior contrasts strongly with that
of usual gauge fields. We point out a possible relation between this result and
those of the numerical simulations of quantum Regge Calculus. We also give a
general quantum formula for the static potential energy of the gravitational
interaction of two masses, which is compatible with the mentioned vacuum
structure.Comment: 7 pages, LaTex, report CTP #2253, November 199
On the Symmetric Space Sigma-Model Kinematics
The solvable Lie algebra parametrization of the symmetric spaces is
discussed. Based on the solvable Lie algebra gauge two equivalent formulations
of the symmetric space sigma model are studied. Their correspondence is
established by inspecting the normalization conditions and deriving the field
transformation laws.Comment: 17 page
Unified description of 0+ states in a large class of nuclear collective models
A remarkably simple regularity in the energies of 0+ states in a broad class
of collective models is discussed. A single formula for all 0+ states in
flat-bottomed infinite potentials that depends only on the number of dimensions
and a simpler expression applicable to all three IBA symmetries in the large
boson number limit are presented. Finally, a connection between the energy
expression for 0+ states given by the X(5) model and the predictions of the IBA
near the critical point is explored.Comment: 4 pages, 3 postscript figures, uses revTe
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