arXiv subjects

Hyeong-Chan Kim

Publications and source records attributed to Hyeong-Chan Kim.

96 records · Page 6Linked to original sources

arXiv1997

The origin of the area law of the entropy of a quantum field in a black hole

It is shown that that the area law for the entropy of a quantum field in the Schwarzschild black hole is due to the quantum statistics. The entropies for one particle, a Boltzmann gas, a quantum mechanical gas obeying Bose-Einstein or Fermi-Dirac statistics, and a quantum field in the Schwarzschild black hole are calculated using the microcanonical ensemble approach and the brick wall method. The area law holds only when the effect of quantum statistics is dominated.

gr-qc↗

arXiv1997

Radiation from a uniformly accelerating harmonic oscillator

We consider a radiation from a uniformly accelerating harmonic oscillator whose minimal coupling to the scalar field changes suddenly. The exact time evolutions of the quantum operators are given in terms of a classical solution of a forced harmonic oscillator. After the jumping of the coupling constant there occurs a fast absorption of energy into the oscillator, and then a slow emission follows. Here the absorbed energy is independent of the acceleration and proportional to the log of a high momentum cutoff of the field. The emitted energy depends on the acceleration and also proportional to the log of the cutoff. Especially, if the coupling is comparable to the natural frequency of the detector ($e^2/(4m) \sim ω_0$) enormous energies are radiated away from the oscillator.

gr-qc↗

arXiv1997

Exact wave functions and geometric phases of a generalized driven oscillator

The generalized invariant and its eigenstates of a general quadratic oscillator are found. The Schrödinger wave functions for the eigenstates are also found in analytically closed forms. The conditions for the existence of the cyclic initial state (CIS) are studied and the corresponding nonadiabatic Berry phase is calculated explicitly.

quant-ph↗

arXiv1996

On the Entropy of a Quantum Field in the 2 + 1 Dimensional Spinning Black Holes

We calculate the entropy of a scalar field in a rotating black hole in 2 + 1 dimension. In the Hartle-Hawking state the entropy is proportional to the horizon area, but diverges linearly in $\sqrt{h}$, where $h$ is the radial cut-off. In WKB approximation the superradiant modes do not contribute to the entropy.

hep-th↗

arXiv1995

Heisenberg-picture approach to the exact quantum motion of a time-dependent forced harmonic oscillator

In the Heisenberg picture, the generalized invariant and exact quantum motions are found for a time-dependent forced harmonic oscillator. We find the eigenstate and the coherent state of the invariant and show that the dispersions of these quantum states do not depend on the external force. Our formalism is applied to several interesting cases.

quant-ph↗

arXiv1993

Bose-Einstein condensation for a self-interacting theory in curved spacetime

The effective action is derived for a self-interacting theory with a finite fixed $O(2)$ charge at finite temperature in curved spacetime. We obtain the high temperature expansion of the effective action in the weak coupling limit. In the relativistic temperature, we discuss about the phase transition in a homogeneous spacetime.

hep-th↗