15078379
Decay of massive scalar hair in the background of a black hole with a global monopole
The late-time tail behaviors of massive scalar fields are examined analytically in the background of a black hole with a global monopole. It is found that the presence of a solid deficit angle in the background metric makes the massive scalar fields decay faster in the intermediate times. However, the asymptotically late-time tail is not affected and it has the same decay rate of $t^{-5/6}$ as in the Schwarzschild and nearly extreme Reissner-Nordstr\"{o}m backgrounds.
119124346
Unruh effect and entanglement generation for accelerated atoms near a reflecting boundary
We study, in the framework of open systems, the entanglement generation of two independent uniformly accelerated atoms in interaction with the vacuum fluctuations of massless scalar fields subjected to a reflecting plane boundary. We demonstrate that, with the presence of the boundary, the accelerated atoms exhibit distinct features from static ones in a thermal bath at the corresponding Unruh temperature in terms of the entanglement creation at the neighborhood of the initial time. In this sense, accelerated atoms in vacuum do not necessarily have to behave as if they were static in a thermal bath at the Unruh temperature.
118525095
Lamb shift for static atoms outside a Schwarzschild black hole
We study, by separately calculating the contributions of vacuum fluctuations and radiation reaction to the atomic energy level shift, the Lamb shift of a static two-level atom interacting with real massless scalar fields in the Boulware, Unruh, and Hartle-Hawking vacuums outside a Schwarzschild black hole. We find that in the Boulware vacuum, the Lamb shift gets a correction arising as a result of the backscattering of vacuum field modes off the space-time curvature, which is reminiscent of the correction to the Lamb shift induced by the presence of cavities. However, when the Unruh and Hartle-Hawking vacua are concerned, our results show that the Lamb shift behaves as if the atom were irradiated by a thermal radiation or immersed in a thermal bath at the Hawking temperature, depending on whether the scalar field is in the Unruh or the Hartle-Hawking vacuum. Remarkably, the thermal radiation is always backscattered by the space-time geometry.
119090796
Fulling–Davies–Unruh effect and spontaneous excitation of an accelerated atom interacting with a quantum scalar field
Abstract We investigate, from the point of view of a coaccelerated frame, the spontaneous excitation of a uniformly accelerated two-level atom interacting with a scalar field in a thermal state at a finite temperature T and show that the same spontaneous excitation rate for the uniformly accelerated atom in the Minkowski vacuum obtained in the inertial frame can only be recovered in the coaccelerated frame assuming a thermal bath at the Fulling–Davies–Unruh temperature T FDU = a / 2 π for what appears to be the Minkowski vacuum to the inertial observer. Our discussion provides another example of a physical process different from those examined before in the literature to better understand the Fulling–Davies–Unruh effect.
115459673
LIGHTCONE FLUCTUATIONS AND EXTRA DIMENSIONS
120986058
Quantum thermal aspects of uniformly accelerating charged black holes
43002203
Black holes and Rindler superspace: Classical singularity and quantum unitarity
Canonical quantization of spherically symmetric initial data appropriate to classical interior black hole solutions in four dimensions is solved exactly without gauge fixing the remaining kinematic Gauss law constraint. The resultant mini-superspace manifold is two dimensional, of signature (+, -), nonsingular, and can be identified with the first Rindler wedge. The associated Wheeler-DeWitt equation with evolution in intrinsic superspace time is a free massive Klein-Gordon equation, and the Hamilton-Jacobi semiclassical limit of plane wave solutions can be matched to the interiors of Schwarzschild black holes. Classical black hole horizons and singularities correspond to the boundaries of the Rindler wedge. Exact wave functions of the Dirac equation in superspace are also considered. Precise correspondence between Schwarzschild black holes and free-particle mechanics in superspace is noted. Despite the presence of classical singularities, Hermiticity of the Dirac Hamiltonian operator, and thus unitarity of the quantum theory, is equivalent to an appropriate boundary condition which must be satisfied by the quantum states. This boundary condition holds for quite generic quantum wave packets of energy eigenstates, but fails for the usual Rindler fermion modes which are eigenstates with zero uncertainty in energy.
118352399
The Origin of the Immirzi Parameter in Loop Quantum Gravity
119198751
Minimal flavor violation in the lepton sector of the Randall–Sundrum model
Abstract We propose a realization of Minimal Flavor Violation in the lepton sector of the Randall–Sundrum model. With the MFV assumption, the only source of flavor violation are the 5 D Yukawa couplings, and the usual two independent sources of flavor violation are related. In the limit of massless neutrinos, the bulk mass matrices and 5 D Yukawa matrices are simultaneously diagonalized, and hence the absence of FCNCs. In the case of massive neutrinos, the contributions to FCNCs in the charged lepton sector are highly suppressed, due to the smallness of neutrino masses. In addition, the MFV assumption also allows suppressing one-loop charged current contributions to flavor changing processes by reducing the size of the Yukawa couplings, which is not possible in the generic anarchical case. We found that the first KK mass scale as low as ∼ 3 TeV can be allowed. In both cases, we present a set of numerical results that give rise to realistic lepton masses and mixing angles. Mild hierarchy in the 5 D Yukawa matrix of O ( 25 ) in our numerical example is required to be consistent with two large and one small mixing angles. This tuning could be improved by having a more thorough search of the parameter space.
16705538
PQCD study of the BSL and nc controversy in inclusive B decays
We calculate the semileptonic branching fraction and charm yield from inclusive $B$ decays using the formalism of perturbative QCD. For nonleptonic decays, we employ the modified factorization theorem, in which Wilson coefficients evolve with the characteristic scales of the decay modes. It is found that the decay rate of the single-charm mode $\stackrel{\ensuremath{\rightarrow}}{b}c\ifmmode \bar{u}\else \={u}\fi{}d$ is enhanced, and a lower ${B}_{\mathrm{SL}}$ is obtained without increasing ${n}_{c}.$ This conclusion differs from the usual one, where the $\stackrel{\ensuremath{\rightarrow}}{b}c\overline{c}s$ mode is increased. Our result for the $B$ meson lifetime is also consistent with the data.
18104286
MODIFICATION OF KAWAI MODEL ABOUT THE MIXING OF THE PSEUDOSCALAR MESONS
The Kawai model describing the glueball–quarkonia mixing is modified. The mixing of η, η′ and η(1410) is re-investigated based on the modified Kawai model. The glueball–quarkonia content of the three states is determined from a fit to the data of the electromagnetic decays involving η, η′. Some predictions about the electromagnetic decays involving η(1410) are presented.