2020-03-06 11:00  P7F

Entropy generation and decay of the cosmological constant in de Sitter space

Hiroyuki Kitamoto

We investigated quantum infrared dynamics in Einstein gravity with a positive cosmological constant. At the one-loop level, the gravitational fluctuation at the superhorizon scale dynamically screens the cosmological constant, and the Gibbons-Hawking entropy increases simultaneously. That is to say, quantum gravity on de Sitter background gives rise to an inflation picture associated with entropy generation. Furthermore, we found that the Gibbons-Hawking entropy can be identified with the von Neumann entropy of the conformal zero mode. We derived the one-loop beta function from the von Neumann entropy. Solving the renormalization group equation exactly, we found that at a late time, the Hubble parameter decays logarithmically with the cosmic time.