Young-Jai Park

Black hole thermodynamics with generalized uncertainty principle

Abstract We apply the generalized uncertainty principle to the thermodynamics of a small black hole. Here we have a black hole system with the UV cutoff. It is shown that the minimal length induced by the GUP interrupts the Gross–Perry–Yaffe phase transition for a small black hole. In order to see whether the black hole remnant takes place a transition to a large black hole, we introduce a black hole in a cavity (IR system). However, we fail to show the phase transition of the remnant to the large black hole.

Entropy of the Schwarzschild black hole to all orders in the Planck length

Considering corrections to all orders in the Planck length on the quantum state density from a generalized uncertainty principle (GUP), we calculate the statistical entropy of the scalar field on the background of the Schwarzschild black hole without any cutoff. We obtain the entropy of the massive scalar field proportional to the horizon area.

Partial teleportation of entanglement in a noisy environment

Abstract Partial teleportation of entanglement is to teleport one particle of an entangled pair through a quantum channel. This is conceptually equivalent to quantum swapping. We consider the partial teleportation of entanglement in the noisy environment, employing the Werner-state representation of the noisy channel for the simplicity of calculation. To have the insight of the many-body teleportation, we introduce the measure of correlation information and study the transfer of the correlation information and entanglement. We find that the fidelity becomes smaller as the initial state is entangled more for a given entanglement of the quantum channel. The entangled channel transfers at least some of the entanglement to the final state.

Thermodynamics and evaporation of the noncommutative black hole

We investigate the thermodynamics of the noncommutative black hole whose static picture is similar to that of the nonsingular black hole known as the de Sitter-Schwarzschild black hole. It turns out that the final remnant of extremal black hole is a thermodynamically stable object. We describe the evaporation process of this black hole by using the noncommutativity-corrected Vaidya metric. It is found that there exists a close relationship between thermodynamic approach and evaporation process.

Entropy of the Randall-Sundrum brane world with the generalized uncertainty principle

By introducing the generalized uncertainty principle, we calculate the entropy of the bulk scalar field on the Randall-Sundrum brane background without any cutoff. We obtain the entropy of the massive scalar field proportional to the horizon area. Here, we observe that the mass contribution to the entropy exists in contrast to all previous results of the usual black hole cases with the generalized uncertainty principle.

Entropy of a charged black hole in two dimensions without cutoff

By introducing the generalized uncertainty principle (GUP) on quantum density states, we obtain a consistent entropy of a scalar field on the (1 + 1)-dimensional Maxwell-dilaton background without an artificial cutoff in contrast to the results of the brick wall model, which depends on the choice of the Hawking temperature for the extremal case.

Entropy in the Kerr - Newman black hole

The entropy of the Kerr - Newman black hole is calculated via the brick-wall method while paying careful attention to the contribution of superradiant scalar modes. It turns out that the nonsuperradiant and superradiant modes contribute simultaneously to the entropy with the same order in terms of the brick-wall cut-off . In particular, the contribution of the superradiant modes to the entropy is negative. To avoid divergence in this method when the angular velocity tends to zero, we propose to introduce a lower bound of angular velocity and to treat the case of the angular momentum per unit mass a = 0 separately. Moreover, from the lower bound of the angular velocity, we obtain the dependence structure of the brick-wall cut-off, which naturally requires an angular cut-off . Finally, if the cut-off values, and , satisfy a proper relation between them, the resulting entropy satisfies the area law.

Quantum key distribution with blind polarization bases.

We propose a new quantum key distribution scheme that uses the blind polarization basis. In our scheme the sender and the receiver share key information by exchanging qubits with arbitrary polarization angles without basis reconciliation. As only random polarizations are transmitted, our protocol is secure even when a key is embedded in a not-so-weak coherent-state pulse. We show its security against the photon-number splitting attack and the impersonation attack.

Entropy of the BTZ black hole in 2+1 dimensions

We semi-classically calculate the entropy of a scalar field in the background of the BTZ black hole, and derive the perimeter law of the entropy. The proper length from the horizon to the ultraviolet cutoff is independent of both the mass and the angular momentum of the black hole. It is shown that the superradiant scattering modes give the sub-leading order contribution to the entropy while the non-superradiant modes give the leading order one, and thus superradiant effect is minor.

Quantum cooling evaporation process in regular black holes

Abstract We investigate a universal behavior of thermodynamics and evaporation process for the regular black holes. We observe an important point where the temperature is maximum, the heat capacity is changed from negative infinity to positive infinity, and the free energy is minimum. Furthermore, this point separates the evaporation process into the early stage with negative heat capacity and the late stage with positive heat capacity. The latter represents the quantum cooling evaporation process. As a result, the whole evaporation process could be regarded as the inverse Hawking–Page phase transition.