4,269 research outputs found
(2 + 1) noncommutative gravity and conical spacetimes
We solve (2+1) noncommutative gravity coupled to point-like sources. We find
continuity with Einstein gravity since we recover the classical gravitational
field in the limit or at large distance from the source. It
appears a limitation on the mass which is twice than expected. Since the
distance is not gauge invariant, the measure of the deficit angle near the
source is intrinsically ambiguous, with the gauge group playing the role of
statistical ensemble. Einstein determinism can be recovered only at large
distance from the source, compared with the scale of the noncommutative
parameter .Comment: 19 pages, LaTeX, no figure
Elliptic algebra U_{q,p}(^sl_2): Drinfeld currents and vertex operators
We investigate the structure of the elliptic algebra U_{q,p}(^sl_2)
introduced earlier by one of the authors. Our construction is based on a new
set of generating series in the quantum affine algebra U_q(^sl_2), which are
elliptic analogs of the Drinfeld currents. They enable us to identify
U_{q,p}(^sl_2) with the tensor product of U_q(^sl_2) and a Heisenberg algebra
generated by P,Q with [Q,P]=1. In terms of these currents, we construct an L
operator satisfying the dynamical RLL relation in the presence of the central
element c. The vertex operators of Lukyanov and Pugai arise as `intertwiners'
of U_{q,p}(^sl_2) for level one representation, in the sense to be elaborated
on in the text. We also present vertex operators with higher level/spin in the
free field representation.Comment: 49 pages, (AMS-)LaTeX ; added an explanation of integration contours;
added comments. To appear in Comm. Math. Phys. Numbering of equations is
correcte
Interparticle Potential up to Next-to-leading Order for Gravitational, Electrical, and Dilatonic Forces
Long-range forces up to next-to-leading order are computed in the framework
of the Einstein-Maxwell-dilaton system by means of a semiclassical approach to
gravity. As has been recently shown, this approach is effective if one of the
masses under consideration is significantly greater than all the energies
involved in the system. Further, we obtain the condition for the equilibrium of
charged masses in the system.Comment: 19 pages, 19 figures, RevTeX4.1. Revised version, Title change
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