Bouncing universe in a heat bath

Abstract

We develop a thermal description to photon modes within the context of bouncing universe. To do so, we start with a Lorentz-breaking dispersion relation which accounts for modified Friedmann equations with a bounce solution. We calculate the spectral radiance, the entropy, the Helmholtz free energy, the heat capacity, and the mean energy. Nevertheless, the latter two ones turn out to contribute only in a trivial manner. More so, all the results are derived analytically and three different regimes of temperature of the universe are also considered, i.e., the inflationary era, the electroweak epoch and the cosmic microwave background.

Exploring antisymmetric tensor effects on black hole shadows and quasinormal frequencies

“…In these models, a vector field, termed the bumblebee field, acquires a non-zero vacuum expectation value (VEV). This aspect establishes a distinct direction, resulting in the local Lorentz invariance violation for particles, which in turn leads to remarkable consequences for instance to the thermodynamic properties [21][22][23][24][25][26][27][28][29][30][31].…”

An exact stationary axisymmetric vacuum solution within a metric-affine bumblebee gravity

“…The thermal properties within the context of LSB have been initially proposed in [33]. After that, recently many works have been made in various scenarios, such as linearized gravity [34], Pospelov and Myers-Pospelov [35,36] electrodynamics, CPT-even and CPT-odd LV terms [37][38][39][40], higher-dimensional operators [41,42], bouncing universe [43], rainbow gravity [44], and Einstein-aether theory [45].…”