# The Modern Physics of Compact Stars and Relativistic Gravity 2019

17-21 September 2019
Yerevan, Armenia
Etc/GMT+4 timezone

## Quantum effects for a spherical shell in the Milne universe

20 Sep 2019, 16:30
30m
Yerevan, Armenia

#### Yerevan, Armenia

Department of Physics, Alex Manoogian str. 1, Yerevan, Armenia

### Speaker

Mr Tigran Petrosyan (Yerevan State University)

### Description

The influence of a spherical boundary on the vacuum fluctuations of a massive scalar field is investigated in background of $\left( D+1\right)$-dimensional Milne universe, assuming that the field obeys Robin boundary condition on the sphere. The normalized mode functions are derived for the regions inside and outside the sphere. For the interior region, the boundary-induced contribution is explicitly extracted in the Wightman function with the help of the generalized Abel-Plana summation formula. The vacuum expectation values (VEVs) of the field squared and of the energy-momentum tensor are investigated for the conformal vacuum. They are decomposed into the boundary-free and boundary-induced contributions. For the latter, rapidly convergent integral representations are provided. In addition to the diagonal components, the vacuum energy-momentum tensor has an off-diagonal component that describes energy flux along the radial direction.

### Primary authors

Prof. Aram Saharian (Yerevan State University ) Mr Tigran Petrosyan (Yerevan State University)