261 research outputs found
Hawking Radiation of Black p-Branes from Gravitational Anomaly
We investigate the Hawking radiation of black -branes of superstring
theories using the method of anomaly cancelation, specially, we use the method
of [S. Iso, H. Umetsu and F. Wilczek, {\sl Phys. Rev. Lett.} {\bf 96}, 151302
(2006); {\sl Phys. Rev. D} {\bf 74}, 044017 (2006)]. The metrics of black
-branes are spherically symmetric, but not the Schwarzschild type. In order
to simplify the calculation, we first make a coordinate transformation to
transform the metric to the Schwarzschild type. Then we calculate its
energy-momentum flux from the method of anomaly cancelation of the above
mentioned references. The obtained energy-momentum flux is equal to a black
body radiation, the thermodynamic temperature of the radiation is equal to its
Hawking temperature. And we find that the results are not changed for the
original non-Schwarzschild type spherically symmetric metric.Comment: 19 pages Latex, some mistakes correcte
(2E,6E)-2,6-Difurfurylidenecyclohexanone
The complete molecule of the title compound, C16H14O3, is generated by crystallographic mirror symmetry, with two C atoms and one O atom lying on the mirror plane. The molecule adopts an E configuration about the C=C bond and the dihedral angle between the furan rings is 16.1 (2)°
Causality in Non-Commutative Quantum Field Theories
We study causality in non-commutative quantum field theory with a space-space
non-commutativity. We employ the S-operator approach of Bogoliubov-Shirkov(BS).
We generalize the BS criterion of causality to the noncommutative theory. The
criterion to test causality leads to a nonzero difference between T*-product
and T-product as a condition of causality violation for a spacelike separation.
We discuss two examples; one in a scalar theory and one in the Yukawa theory.
In particular, in the context of a non-commutative Yukawa theory, with the
interaction Lagrangian , is observed to
be causality violating even in case of space-space noncommutativity for which
\theta^{0i}=0.
\Comment: 18 pages, LaTeX; A few changes in sections 3.2,3.3 and
Chlorido(5-formyl-2-hydroxyphenyl-κC 1)mercury(II)
In the planar (r.m.s. deviation = 0.027 Å) title compound, [Hg(C7H5O2)Cl], the HgII atom shows a typical linear coordination by a C atom of the benzene ring and a Cl atom. Intermolecular O—H⋯O hydrogen bonds are present in the crystal structure, resulting in chains propagating along the b axis. The crystal studied was a non-merohedral twin, with a twin ratio of 0.802 (2):0.198 (2)
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