The quantum fluctuations of the stress tensor of a quantum field are discussed , as are the resulting spacetime metric fluctuations. Passive quantum gravity is an approximation in which gravity is not directly quantized, but fluctuations of the spacetime geometry are driven by stress tensor fluctuations. We discuss a decomposition of the stress tensor correlation function into three parts, and ...

A relativistic modified gravity (MOG) called Scalar-Tensor-Vector Gravity (STVG) desribes a self-consistent, stable gravity theory that contains Einstein’s general relativity in a well-defined limit. The theory has an extra degree of freedom, a vector field called a “phion” field whose curl is a skew symmetric field that couples to matter (“fifth force”). The spacetime geometry is described by ...

We construct an asymmetric bouncing scenario within the VCDM model - also known as type-II minimally modified gravity -, a theory with two local physical degrees of freedom. The is exempt any ghost or gradient instability, ad-hoc matching conditions anisotropic stress issue (BKL instability). It moreover succeeds in generating cosmological perturbations compatible observations. scalar spectral ...

We argue that gravity theories in AdS4 are holographically dual to either of two threedimensional CFT’s: the usual Dirichlet CFT1 where the fixed graviton acts as a source for the stress-energy tensor, and a dual CFT2 with a fixed dual graviton which acts as a source for a dual stress-energy tensor. The dual stress-energy tensor is shown to be the Cotton tensor of the Dirichlet CFT. The two CFT...

A theory of gravity with torsion is examined in which the torsion tensor is constructed from the exterior derivative of an antisymmetric rank two potential plus the dual of the gradient of a scalar field. Field equations for the theory are derived by demanding that the action be stationary under variations with respect to the metric, the antisymmetric potential, and the scalar field. A material...