Semiclassical Universe from First Principles

Corrections to Hawking-like Radiation for a Friedmann- Robertson-Walker Universe

Recently, a Hamilton-Jacobi method beyond semiclassical approximation in black hole physics was developed by Banerjee and Majhi [29]. In this paper, we generalize their analysis of black holes to the case of Friedmann-Robertson-Walker (FRW) universe. It is shown that all the higher order quantum corrections in the single particle action are proportional to the usual semiclassical contribution. ...

First principles semiclassical calculations of vibrational eigenfunctions.

Vibrational eigenfunctions are calculated on-the-fly using semiclassical methods in conjunction with ab initio density functional theory classical trajectories. Various semiclassical approximations based on the time-dependent representation of the eigenfunctions are tested on an analytical potential describing the chemisorption of CO on Cu(100). Then, first principles semiclassical vibrational ...

Transition from AdS universe to DS universe in the BPP model

Myungseok Yoon Center for Quantum Spacetime, Sogang University, Seoul 121-742, Korea (Dated: March 6, 2007) Abstract It can be shown that in the BPP model the smooth phase transition from the asymptotically decelerated AdS universe to the asymptotically accelerated DS universe is possible by solving the modified semiclassical equations of motion. This transition comes from noncommutative Poisso...

First - Principles Semiclassical Initial Value Representation

Quantum Fluctuations and Particle Production of Coherently Oscillating Inflaton

We study a massive inflaton minimally coupled to FRW Universe using the semiclassical gravity derived from canonical quantum gravity. It is found that the semiclassical quantum gravity leads to the power-law expansion t2/3 in an oscillatory phase of the inflaton. The particle production of the inflaton in the expanding Universe restricts the duration of stable coherent oscillations and parametr...