منابع مشابه
Troubles for Unimodular Gravity
We compute the contribution of various gravitational instantons to the path integral in the standard formulation of unimodular gravity, an alternative theory of gravity where the determinant of the metric is not dynamical. Following similar computations in General Relativity, we derive the entropy/area ratio for cosmological and black hole horizons, finding in general disagreement with General ...
متن کاملNo conformal anomaly in unimodular gravity
The conformal invariance of unimodular gravity survives quantum corrections, even in the presence of conformal matter. Unimodular gravity can actually be understood as a certain truncation of the full Einstein-Hilbert theory, where in the Einstein frame the metric tensor has unit determinant. Our result is compatible with the idea that the corresponding restriction in the functional integral is...
متن کاملThe quantization of unimodular gravity and the cosmological constant problems
A quantization of unimodular gravity is described, which results in a quantum effective action which is also unimodular, ie a function of a metric with fixed determinant. A consequence is that contributions to the energy momentum tensor of the form of gabC , where C is a spacetime constant, whether classical or quantum, are not sources of curvature in the equations of motion derived from the qu...
متن کاملThe Renormalization Group flow of unimodular f(R) gravity
Unimodular gravity is classically equivalent to General Relativity. This equivalence extends to actions which are functions of the curvature scalar. At the quantum level, the dynamics could differ. Most importantly, the cosmological constant is not a coupling in the unimodular action, providing a new vantage point from which to address the cosmological constant fine-tuning problem. Here, a quan...
متن کاملUnimodular gravity and general relativity from graviton self-interactions
It is commonly accepted that general relativity is the only solution to the consistency problem that appears when trying to build a theory of interacting gravitons (massless spin-2 particles). Padmanabhan’s 2008 thought-provoking analysis raised some concerns that are having resonance in the community. In this paper we present the self-coupling problem in detail and explicitly solve the infinit...
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ژورنال
عنوان ژورنال: Journal of Cosmology and Astroparticle Physics
سال: 2013
ISSN: 1475-7516
DOI: 10.1088/1475-7516/2013/01/014