Spin-other-orbit matrix elements for f sup 4 configurations

Data for spin orbit matrix elements for f to 4th power configuratio

Configuration interaction matrix elements for d sup n configurations

Configuration interaction matrix elements for weak interaction

Matrix elements of the spin-spin interactions for f sup 4 configurations

Matrix elements of spin-spin interactions for F4 electron configuration

Primordial torsion fields as an explanation of the anisotropy in cosmological electromagnetic propagation

In this note we provide a simple explanation of the recent finding of anisotropy in electromagnetic (EM) propagation claimed by Nodland and Ralston (astro-ph/9704196). We consider, as a possible origin of such effect, the effective coupling between EM fields and some tiny background torsion field. The coupling is obtained after integrating out charged fermions, it is gauge invariant and does not require the introduction of any new physics.Comment: 8 pages, LaTeX, one figure, enlarged version with minor correction

Matrix elements of atomic interaction operators for d sup n configurations

Tabulation of matrix elements of atomic interaction operators for various configuration

Does Inflation Provide Natural Initial Conditions for the Universe?

If our universe underwent inflation, its entropy during the inflationary phase was substantially lower than it is today. Because a low-entropy state is less likely to be chosen randomly than a high-entropy one, inflation is unlikely to arise through randomly-chosen initial conditions. To resolve this puzzle, we examine the notion of a natural state for the universe, and argue that it is a nearly-empty spacetime. If empty space has a small vacuum energy, however, inflation can begin spontaneously in this background. This scenario explains why a universe like ours is likely to have begun via a period of inflation, and also provides an origin for the cosmological arrow of time.Comment: Submitted to Gravity Research Foundation Essay Competition; based on hep-th/041027

Nonlocal Cosmology

We explore nonlocally modified models of gravity, inspired by quantum loop corrections, as a mechanism for explaining current cosmic acceleration. These theories enjoy two major advantages: they allow a delayed response to cosmic events, here the transition from radiation to matter dominance, and they avoid the usual level of fine tuning; instead, emulating Dirac's dictum, the required large numbers come from the large time scales involved. Their solar system effects are safely negligible, and they may even prove useful to the black hole information problem.Comment: Expanded(!) version, to appear in Phys. Rev. Letter

Cosmic Acceleration Data and Bulk-Brane Energy Exchange

We consider a braneworld model with bulk-brane energy exchange. This allows for crossing of the w=-1 phantom divide line without introducing phantom energy with quantum instabilities. We use the latest SnIa data included in the Gold06 dataset to provide an estimate of the preferred parameter values of this braneworld model. We use three fitting approaches which provide best fit parameter values and hint towards a bulk energy component that behaves like relativistic matter which is propagating in the bulk and is moving at a speed v along the fifth dimension, while the bulk-brane energy exchange component corresponds to negative pressure and signifies energy flowing from the bulk into the brane. We find that the best fit effective equation of state parameter $w_{eff}$ marginally crosses the phantom divide line w=-1. Thus, we have demonstrated both the ability of this class of braneworld models to provide crossing of the phantom divide and also that cosmological data hint towards natural values for the model parameters.Comment: 12 pages, 2 figures, added comments, references update

Observational signatures of f(R) dark energy models that satisfy cosmological and local gravity constraints

We discuss observational consequences of f(R) dark energy scenarios that satisfy local gravity constraints (LGC) as well as conditions of the cosmological viability. The model we study is given by m(r)=C(-r-1)^p (C>0, p>1) with m=Rf_{,RR}/f_{,R} and r=-Rf_{,R}/f, which cover viable f(R) models proposed so far in a high-curvature region designed to be compatible with LGC. The equation of state of dark energy exhibits a divergence at a redshift z_c that can be as close as a few while satisfying sound horizon constraints of Cosmic Microwave Background (CMB). We study the evolution of matter density perturbations in details and place constraints on model parameters from the difference of spectral indices of power spectra between CMB and galaxy clustering. The models with p>5 can be consistent with those observational constraints as well as LGC. We also discuss the evolution of perturbations in the Ricci scalar R and show that an oscillating mode (scalaron) can easily dominate over a matter-induced mode as we go back to the past. This violates the stability of cosmological solutions, thus posing a problem about how the over-production of scalarons should be avoided in the early universe.Comment: 13 pages, 7 figures, version to appear in Physical Review

Hawking radiation, Unruh radiation and the equivalence principle

We compare the response function of an Unruh-DeWitt detector for different space-times and different vacua and show that there is a {\it detailed} violation of the equivalence principle. In particular comparing the response of an accelerating detector to a detector at rest in a Schwarzschild space-time we find that both detectors register thermal radiation, but for a given, equivalent acceleration the fixed detector in the Schwarzschild space-time measures a higher temperature. This allows one to locally distinguish the two cases. As one approaches the horizon the two temperatures have the same limit so that the equivalence principle is restored at the horizon.Comment: 9 pages. Added references and added discussion. To be published in PR