118559190
Casimir-Polder-like force on an atom outside a Schwarzschild black hole
Abstract We calculate, in the framework of open quantum systems, the ground state energy-level shift for a static two-level atom outside a spherically symmetric black hole in interaction with fluctuating massless scalar fields in the Boulware and Unruh vacuums. We find that the energy-level shift is position dependent and thus gives rise to a force on the atom besides the classical gravitational force. For the case of the Boulware vacuum that represents a star which has not collapsed through its event horizon, this force is attractive near the horizon and is repulsive far away from the black hole with a behavior of r−3. For the case of the Unruh vacuum which represents a radiating black hole, we find that the contribution to the Casimir-Polder-like force due to the presence of Hawking radiation is always attractive and, remarkably, this attractive force diverges at the event horizon.
115459673
LIGHTCONE FLUCTUATIONS AND EXTRA DIMENSIONS
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.
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.
119913697
BLACK-HOLE ENTROPY AND HORIZON AREA
120986058
Quantum thermal aspects of uniformly accelerating charged black holes
40534119
Synchrotron radiation monitoring system at BEPC
The synchrotron radiation by the relativistic particles is a useful and important diagnostic tool to obtain various beam parameters. The visible light of the synchrotron radiation emitted in a bending magnet of the BEPC storage ring is reflected through the window by a water-cooled mirror in the vacuum chamber and then directed by a remote controlled mirror onto the optical bench supporting the diagnostic instruments in the dark room. These instruments include a CCD camera providing the image of the beam transverse profile on a TV monitor, a lens system focusing the synchrotron light onto a solid state scanned photodiode arrays to obtain the beam height or width, a streak camera to measure the bunch length for a single pass, and a two-dimensional position sensing photo-detector to monitoring the drift of the beam position. This paper gives the detailed description of the synchrotron radiation monitoring system at BEPC.
122878082
Induced Topological Terms, Hidden Local Symmetry, and Anyon Superconductivity
We show how the topological Chern-Simons term in three dimensions and the θ-term, in four dimensions can be dynamically generated due to quantum fluctuations in Nambu-Jona-Lasinio models. These results give a vivid demonstration of hidden local symmetry at work. The fluctuation-induced Chern-Simons term provides a natural way to incorporate fractional statistics and thus a more direct connection with anyon superconductivity. Possible phenomenological implications of this approach in particle physics are also discussed.
119114689
Gamma ray line constraints on effective theories of dark matter
Abstract A monochromatic gamma ray line results when dark matter particles in the galactic halo annihilate to produce a two body final state which includes a photon. Such a signal is very distinctive from astrophysical backgrounds, and thus represents an incisive probe of theories of dark matter. We compare the recent null results of searches for gamma ray lines in the galactic center and other regions of the sky with the predictions of effective theories describing the interactions of dark matter particles with the Standard Model. We find that the null results of these searches provide constraints on the nature of dark matter interactions with ordinary matter which are complementary to constraints from other observables, and stronger than collider constraints in some cases.
118099142
Ruling Out the Light Higgs Boson by Kaon Decay
We re-examine the theoretical estimates of the decay K → πH and the experimental constraints on the existence of a light Higgs boson from this process. We find that: (i) pole diagrams generated from the Higgs-gluon coupling via a loop of heavy quarks do contribute to K → πH, (ii) there is an additional contribution to the K → πH amplitude coming from the effective KHW and πHW couplings, (iii) even if B, the unknown parameter in the chiral-Lagrangian description of K → πH transitions, is nonzero and even if the real part of the K → πH amplitude is canceled accidentally, the imaginary contribution alone suffices to rule out a Higgs boson lighter than 2m π, and (iv) whether Higgs bosons in the mass range 2m π < m H < 350 MeV are excluded by the imaginary part of the K → πH amplitude depends on the branching ratio of H → µ + µ -,a+p, — and the top-quark mass. Decay modes K L → π+π- H and K + → l+ vH are briefly discussed.
124014107
Extraction of V(ub) from decay B ---> pi lepton neutrino