Emil Mottola

Dynamics of the Conformal Mode and Simplicial Gravity

Was) Cosmologywithdecayingvacuumenergy*

Motivated by recent attempts to solve the cosmological constant problem, we examine the observational consequences of a vacuum energy which decays in time. In both radiation and matter dominated eras, the ratio of the vacuum to the total energy density of the universe must be small. Although the vacuum cannot provide the “missing mass” required to close the universe today, -

Gravitationally Induced Neutrino - Oscillation Phases " Tanmoy Bhattacharya

We critically examine the recent claim of a \new eeect" of gravitationally induced quantum mechanical phases in neutrino oscillations. A straightforward exercise in the Schwarzschild coordinates appropriate to a spherically symmetric non-rotating star shows that, although there is a general relativis-tic eeect of the star's gravity on neutrino oscillations, it is not of the form claimed, and is...

Functional Integration over Geometries

The geometric construction of the functional integral over coset spaces M/G is reviewed. The inner product on the cotangent space of infinitesimal deformations of M defines an invariant distance and volume form, or functional integration measure on the full configuration space. Then, by a simple change of coordinates parameterizing the gauge fiber G, the functional measure on the coset space M/...

The Conformal Mode in 2D Simplicial Gravity

We verify that summing 2D DT geometries correctly reproduces the Polyakov action for the conformal mode, including all ghost contributions, at large volumes. The Gaussian action is reproduced even for cm = 10, well into the branched polymer phase, which confirms the expectation that the DT measure is indeed correct in this regime as well Introduction. In the last decade there has been considera...