# Unimodular quantum gravity and the cosmological constant

@article{Percacci2018UnimodularQG, title={Unimodular quantum gravity and the cosmological constant}, author={Roberto Percacci}, journal={Foundations of Physics}, year={2018}, volume={48}, pages={1364-1379} }

It is shown that the one-loop effective action of unimodular gravity is the same as that of ordinary gravity, restricted to unimodular metrics. The only difference is in the treatment of the global scale degree of freedom and of the cosmological term. A constant vacuum energy does not gravitate, addressing one aspect of the cosmological constant problem.

## 53 Citations

### Unimodular quantum gravity: steps beyond perturbation theory

- Physics
- 2020

The renormalization group flow of unimodular quantum gravity is computed by taking into account the graviton and Faddeev-Popov ghosts anomalous dimensions. In this setting, a ultraviolet attractive…

### Emergent gravity in superplastic crystals and cosmological constant problem

- Physics
- 2019

We discuss emergent gravity in the superplastic crystals. We restrict ourselves by the consideration of the gapped (massive) fermions coupled to gravity. In this approach the stress - energy tensor…

### Can quantum fluctuations differentiate between standard and unimodular gravity?

- MathematicsJournal of High Energy Physics
- 2021

Abstract
We formally prove the existence of a quantization procedure that makes the path integral of a general diffeomorphism-invariant theory of gravity, with fixed total spacetime volume,…

### Massive unimodular gravity

- Geology, PhysicsClassical and Quantum Gravity
- 2020

A ghost free massive deformation of unimodular gravity (UG), in the spirit of mimetic massive gravity, is shown to exist. This construction avoids the no-go theorem for a Fierz–Pauli type of mass…

### What do gravitons say about (unimodular) gravity?

- Physics, GeologyJournal of High Energy Physics
- 2018

A bstractWe revisit the problem of constraining the weak field limit of the gravitational lagrangian from S-matrix properties. From unitarity and Lorentz invariance of the S-matrix of massless…

### Gauge assisted quadratic gravity: A framework for UV complete quantum gravity

- PhysicsPhysical Review D
- 2018

We discuss a variation of quadratic gravity in which the gravitational interaction remains weakly coupled at all energies, but is assisted by a Yang-Mills gauge theory which becomes strong at the…

### Quantum Gravity: A Fluctuating Point of View

- PhysicsFrontiers in Physics
- 2020

In this contribution, we discuss the asymptotic safety scenario for quantum gravity with a functional renormalization group approach that disentangles dynamical metric fluctuations from the…

### Covariant BRST quantization of unimodular gravity: Formulation with antisymmetric tensor ghosts

- PhysicsPhysical Review D
- 2022

Unimodular gravity (UG) is an interesting theory that may explain why the cosmological constant is extremely small, in contrast to general relativity (GR). The theory has only the transverse…

### The cosmological constant as a boundary term

- PhysicsJournal of High Energy Physics
- 2022

Abstract
We compare the path integral for transition functions in unimodular gravity and in general relativity. In unimodular gravity the cosmological constant is a property of states that are…

### Emergent gravity in superplastic crystals and cosmological constant problem.

- Physics
- 2019

We discuss the scenario, in which quantum gravity emerges in the underlined theory, which is similar to the one describing various excitations in the superplastic crystals. We restrict ourselves by…

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