4,233 research outputs found
SL(2,C) gravity on noncommutative space with Poisson structure
The Einstein's gravity theory can be formulated as an SL(2,C) gauge theory in
terms of spinor notations. In this paper, we consider a noncommutative space
with the Poisson structure and construct an SL(2,C) formulation of gravity on
such a space. Using the covariant coordinate technique, we build a gauge
invariant action in which, according to the Seiberg-Witten map, the physical
degrees of freedom are expressed in terms of their commutative counterparts up
to the first order in noncommutative parameters.Comment: 12 pages, no figures; v2: 13 pages, clarifications and references
added; v3: clarifications added; v4: more clarifications and references
added, final version to appear in Phys. Rev.
U(2,2) gravity on noncommutative space with symplectic structure
The classical Einstein's gravity can be reformulated from the constrained
U(2,2) gauge theory on the ordinary (commutative) four-dimensional spacetime.
Here we consider a noncommutative manifold with a symplectic structure and
construct a U(2,2) gauge theory on such a manifold by using the covariant
coordinate method. Then we use the Seiberg-Witten map to express noncommutative
quantities in terms of their commutative counterparts up to the first-order in
noncommutative parameters. After imposing constraints we obtain a
noncommutative gravity theory described by the Lagrangian with up to
nonvanishing first order corrections in noncommutative parameters. This result
coincides with our previous one obtained for the noncommutative SL(2,C)
gravity.Comment: 13 pages, no figures; v2: 14 pages, clarifications and references
added; v3: 16 pages, title changed, clarifications and references added; v4:
17 pages, clarifications added, this final version accepted by Physical
Review
Noncommutative corrections to the minimal surface areas of the pure AdS spacetime and Schwarzschild-AdS black hole
Based on the perturbation expansion method, we compute the noncommutative
corrections to the minimal surface areas of the pure AdS spacetime and
Schwarzschild-AdS black hole, where the noncommutaitve background is suitably
constructed in terms of the Poincar\'e coordinate system. In particular, we
find a reasonable tetrad with subtlety, which not only matches the metrics of
the pure AdS spacetime and Schwarzschild-AdS black hole in the commutative
case, but also makes the corrections real rather than complex in the
noncommutative case. For the pure AdS spacetime, the nocommutaitve effect is
only a logarithmic term, while for the Schwarzchild-AdS black hole, it contains
a logarithmic contribution plus a both mass and noncommutative parameter
related term.Comment: v1: 10 pages, no figures; v2: 11 pages, minor clarifications and
references added; v3: minor revisons and references added
DiaquaÂbisÂ(4-carbÂoxy-2-ethyl-1H-imidazole-5-carboxylÂato-κ2 N 3,O 4)manganese(II) N,N-dimethylÂformamide disolvate
In the title compound, [Mn(C7H7N2O4)2(H2O)2]·2C3H7NO, the central MnII ion, located on an inversion center, is hexaÂcoordinated by four O atoms from two water molÂecules and two carboxylÂate groups, and two N atoms from two 4-carbÂoxy-2-ethyl-1H-imidazole-5-carboxylÂate anions in a slightly distorted octaÂhedral environment. The complex molÂecules and solvent molÂecules are connected via N—H⋯O and O—H⋯O hydrogen bonds into a two-dimensional polymeric structure parallel to (001)
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