We consider a class of grand unified theories (GUT's) based on the Georgi-Glashow model in curved spacetime. are particularly concerned with coupling constants involving curvature. These include cosmological and gravitational constants, as well appearing terms quadratic curvature which link Higgs bosons to scalar For asymptotically free theories, we use renormalization group obtain expressions for these effective at high (between GUT Planck scales). discuss role field equations. results may...

Scalar-field theory with a $\ensuremath{\lambda}{\ensuremath{\varphi}}^{4}$ self-interaction is studied in space-times non-Minkowskian topology. An application of the effective potential to symmetry breaking discussed. In addition, expressions for vacuum energy density and topological mass order $\ensuremath{\lambda}$ are obtained which massless at tree-graph level. One cases considered scalar-field version Casimir effect. this case we also obtain one-loop massive scalar field discuss its...

The analogy between field theory at a finite temperature and in periodically identified flat space-time is discussed used to deduce the Casimir effect. renormalization of twisted scalar with $\ensuremath{\lambda}{\ensuremath{\varphi}}^{4}$ self-interaction also discussed.

The renormalization of interacting scalar field theories in general curved space-times is discussed. background-field method used to calculate the effective action. Divergences are analyzed using heat-kernel techniques and dimensional regularization. Renormalization a theory with cubic quartic self-interactions shown at two-loop level four-dimensional space-time. Counterterms, including gravitational ones, computed this order. one-loop action examined for self-interaction six-dimensional As...

We present a model which predicts the temperature of Bose-Einstein condensation in atomic alkali gases and find excellent agreement with recent experimental observations. A system bosons confined by harmonic oscillator potential is not characterized critical same way as an identical confined. discuss problem isotropic analytically numerically for range parameters relevance to study low metals.

We conjecture that the coincidence limit of heat kernel (or Feynman propagator) in curved spacetime can be written a new form which coefficients proper-time series have no terms containing scalar curvature R. This effectively sums all prove our to third order proper time. permits one obtain certain nonlocal effects general through one-loop calculation.

We study the question of gauge dependence quantum gravity contribution to running coupling constant for electromagnetism. The calculations are performed using dimensional regularization in a manifestly gauge-invariant and gauge-condition-independent formulation effective action. It is shown that there no charge, hence alteration asymptotic freedom at high energies as predicted by Robinson Wilczek.

Dynamical symmetry breaking in massless $\ensuremath{\lambda}{\ensuremath{\varphi}}^{4}$ theory curved spacetime with non-conformal coupling to the curvature is investigated. It shown that general one-loop self-energy for such a field will involve term of form $R\mathrm{ln}|R{\ensuremath{\mu}}^{\ensuremath{-}2}|$, where $R$ scalar curvature, and $\ensuremath{\mu}$ mass. This can give rise breaking. Two models, Einstein universe spatially flat Robertson-Walker power-law expansion, are...

We consider a renormalizable quantum field theory, such as grand unified in general curved spacetime. use new partially summed form of the proper-time or heat-kernel expansion propagator to obtain curvature-dependent logarithmic terms effective action. demonstrate connection between these and renormalization group. The explicit curvature dependence permits us modified gravitational equations. are importance for dynamical models early universe, including inflationary models. These also...

The quantum gravitational contribution to the renormalization group behavior of electric charge in Einstein-Maxwell theory with a cosmological constant is considered. Quantum gravity shown lead running not present when vanishes. This reopens possibility, suggested by Robinson and Wilczek, altering scaling gauge theories at high energies although our result differs. We show possibility an ultraviolet fixed point that linked directly constant.

The lowest order quantum corrections to the effective action arising from quantized massive fermion fields in Randall-Sundrum background spacetime are computed. boundary conditions and their relation with gauge invariance examined detail. possibility of Wilson loop symmetry breaking brane models is also analyzed. self-consistency requirements, previously considered case a bulk scalar field, extended include contribution fermions. It shown that this it possible stabilize radius extra...

The problem of gauge and parametrization dependence in self-consistent dimensional reduction five-dimensional quantum gravity is discussed. It shown how the modification background-field method suggested by Vilkovisky crucial for obtaining correct result. We find that there are no physically acceptable solutions form ${\mathrm{R}}^{4}$\ifmmode\times\else\texttimes\fi{}${\mathrm{S}}^{1}$ at one-loop level.

The gauge-invariant background-field approach is used to discuss a non-Abelian gauge theory containing fermions in curved space-time. Renormalization of the at one-loop level presented using dimensional regularization, heat-kernel techniques, and curved---space-time momentum-space method.

Renormalization-group methods are used to study interacting quantum field theory in curved spacetime. Details presented explicitly showing how the short-distance behavior of is linked existence nonlocal terms effective action. We show usual value for running electric charge QED flat spacetime may be obtained this way by using background-field method. A similar technique then find action arising from a real scalar on weakly gravitational background. It shown results coupling constants...

The calculation of quadratic divergences in Einstein-Maxwell theory with a possible cosmological constant is considered. We describe method calculation, using the background-field method, that sensitive to divergences, respectful gauge invariance, and independent conditions. A standard renormalization group analysis applied result where it shown do lead asymptotic freedom as found original paper Robinson Wilczek. role nature these critically evaluated light recent criticism. Within context...

A bstract We consider the one-loop renormalization of a real scalar field interacting with Dirac spinor in curved spacetime. general Yukawa interaction is considered which includes both and pseudoscalar coupling. The assumed to be non-minimally coupled gravitational have quartic self-interaction potential. All group functions are evaluated special case where there no mass scale present classical theory (apart from fields) we evaluate effective action up including order R 2 curvature. In...

We calculate the vacuum expectation value of stress-energy tensor for a quantized bulk scalar field in Randall-Sundrum model and discuss consequences its local behavior self-consistency model. find that, general, diverges vicinity branes. Our main conclusion is that sufficiently complicated it has implications effective potential, or radion stabilization, methods have so far been used.