2,297 research outputs found

### Renormalization group equations and integrability in Hamiltonian systems

We investigate Hamiltonian systems with two degrees of freedom by using
renormalization group method. We show that the original Hamiltonian systems and
the renormalization group equations are integrable if the renormalization group
equations are Hamiltonian systems up to the second leading order of a small
parameter.Comment: 7 pages, No figures, LaTeX (19 kb

### Black Objects in the Gauge Theory of P-Branes

Within the context of the recently formulated classical gauge theory of
relativistic p-branes minimally coupled to general relativity in D-dimensional
spacetimes, we obtain solutions of the field equations which describe black
objects. Explicit solutions are found for two cases: D > p+1 (true p-branes)
and D = p+1 (p-bags).Comment: 9 pages, REVTEX 3.

### Postmodern String Theory: Stochastic Formulation

In this paper we study the dynamics of a statistical ensemble of strings,
building on a recently proposed gauge theory of the string geodesic field. We
show that this stochastic approach is equivalent to the Carath\'eodory
formulation of the Nambu-Goto action, supplemented by an averaging procedure
over the family of classical string world-sheets which are solutions of the
equation of motion. In this new framework, the string geodesic field is
reinterpreted as the Gibbs current density associated with the string
statistical ensemble. Next, we show that the classical field equations derived
from the string gauge action, can be obtained as the semi-classical limit of
the string functional wave equation. For closed strings, the wave equation
itself is completely analogous to the Wheeler-DeWitt equation used in quantum
cosmology. Thus, in the string case, the wave function has support on the space
of all possible spatial loop configurations. Finally, we show that the string
distribution induces a multi-phase, or {\it cellular} structure on the
spacetime manifold characterized by domains with a purely Riemannian geometry
separated by domain walls over which there exists a predominantly Weyl
geometry.Comment: 24pages, ReVTe

### The back reaction and the effective Einstein's equation for the Universe with ideal fluid cosmological perturbations

We investigate the back reaction of cosmological perturbations on the
evolution of the Universe using the renormalization group method. Starting from
the second order perturbed Einstein's equation, we renormalize a scale factor
of the Universe and derive the evolution equation for the effective scale
factor which includes back reaction due to inhomogeneities of the Universe. The
resulting equation has the same form as the standard Friedman-Robertson-Walker
equation with the effective energy density and pressure which represent the
back reaction effect.Comment: 16 pages, to appear in Phys. Rev.

### The Planck Scale from Top Condensation

We propose a scenario in which the Planck scale is dynamically linked to the
electroweak scale induced by top condensation. The standard model field
content, without the Higgs, is promoted to a 5D warped background. There is
also an additional 5D fermion with the quantum numbers of the right-handed top.
Localization of the zero-modes leads, at low energies, to a Nambu-Jona-Lasinio
model that also stabilizes the radion field dynamically thus explaining the
hierarchy between the Planck scale and v_EW = 174 GeV. The top mass arises
dynamically from the electroweak breaking condensate. The other standard model
fermion masses arise naturally from higher-dimension operators, and the fermion
mass hierarchies and flavor structure can be explained from the localization of
the zero-modes in the extra dimension. If any other contributions to the radion
potential except those directly related with electroweak symmetry breaking are
engineered to be suppressed, the KK scale is predicted to be about two orders
of magnitude above the electroweak scale rendering the model easily consistent
with electroweak precision data. The model predicts a heavy (composite) Higgs
with a mass of about 500 GeV and standard-model-like properties, and a
vector-like quark with non-negligible mixing with the top quark and mass in the
1.6 - 2.9 TeV range. Both can be within the reach of the LHC. It also predicts
a radion with a mass of a few GeV that is very weakly coupled to standard model
matter.Comment: 41 pages, 7 figures; added references, minor changes in the
electroweak precision constraints section; final version in PR

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