scholarly journals Large Quantum Gravity Effects: Backreaction on Matter

1997 ◽  
Vol 12 (32) ◽  
pp. 2407-2413 ◽  
Author(s):  
Rodolfo Gambini ◽  
Jorge Pullin

We re-examine the large quantum gravity effects discovered by Ashtekar in the context of (2+1)-dimensional gravity coupled to matter. We study an alternative one-parameter family of coherent states of the theory in which the large quantum gravity effects on the metric can be diminished, at the expense of losing coherence in the matter sector. Which set of states is the one that occurs in nature will determine if the large quantum gravity effects are actually observable as wild fluctuations of the metric or rapid loss of coherence of matter fields.

1999 ◽  
Vol 60 (6) ◽  
Author(s):  
Alfredo E. Dominguez ◽  
Manuel H. Tiglio

1991 ◽  
Vol 06 (08) ◽  
pp. 1385-1406 ◽  
Author(s):  
MASAFUMI FUKUMA ◽  
HIKARU KAWAI ◽  
RYUICHI NAKAYAMA

We study the continuum Schwinger-Dyson equations for nonperturbative two-dimensional quantum gravity coupled to various matter fields. The continuum Schwinger-Dyson equations for the one-matrix model are explicitly derived and turn out to be a formal Virasoro condition on the square root of the partition function, which is conjectured to be the τ function of the KdV hierarchy. Furthermore, we argue that general multi-matrix models are related to the W algebras and suitable reductions of KP hierarchy and its generalizations.


1993 ◽  
Vol 08 (01) ◽  
pp. 33-43 ◽  
Author(s):  
E. ELIZALDE ◽  
S.D. ODINTSOV

Two-dimensional Maxwell-dilaton quantum gravity, which covers a large family of the actions for two-dimensional gravity (in particular, string-inspired models) is investigated. Charged black holes which appear in the theory are briefly discussed. The one-loop divergences in the linear covariant gauges are calculated. It is shown that for some choices of the dilaton potential and dilaton-Maxwell coupling, the theory is one-loop multiplicatively renormalizable (or even finite). A comparison with the divergences structure of four-dimensional Einstein-Maxwell gravity is given.


2019 ◽  
Vol 790 ◽  
pp. 229-236 ◽  
Author(s):  
Sebastián A. Franchino-Viñas ◽  
Tibério de Paula Netto ◽  
Ilya L. Shapiro ◽  
Omar Zanusso

2000 ◽  
Vol 09 (06) ◽  
pp. 669-686 ◽  
Author(s):  
MARÍA E. ANGULO ◽  
GUILLERMO A. MENA MARUGÁN

Linearly polarized cylindrical waves in four-dimensional vacuum gravity are mathematically equivalent to rotationally symmetric gravity coupled to a Maxwell (or Klein–Gordon) field in three dimensions. The quantization of this latter system was performed by Ashtekar and Pierri in a recent work. Employing that quantization, we obtain here a complete quantum theory which describes the four-dimensional geometry of the Einstein–Rosen waves. In particular, we construct regularized operators to represent the metric. It is shown that the results achieved by Ashtekar about the existence of important quantum gravity effects in the Einstein–Maxwell system at large distances from the symmetry axis continue to be valid from a four-dimensional point of view. The only significant difference is that, in order to admit an approximate classical description in the asymptotic region, states that are coherent in the Maxwell field need not contain a large number of photons anymore. We also analyze the metric fluctuations on the symmetry axis and argue that they are generally relevant for all of the coherent states.


2011 ◽  
Vol 52 (5) ◽  
pp. 052502 ◽  
Author(s):  
Laurent Freidel ◽  
Etera R. Livine

1991 ◽  
Vol 06 (15) ◽  
pp. 2743-2754 ◽  
Author(s):  
NORISUKE SAKAI ◽  
YOSHIAKI TANII

The radius dependence of partition functions is explicitly evaluated in the continuum field theory of a compactified boson, interacting with two-dimensional quantum gravity (noncritical string) on Riemann surfaces for the first few genera. The partition function for the torus is found to be a sum of terms proportional to R and 1/R. This is in agreement with the result of a discretized version (matrix models), but is quite different from the critical string. The supersymmetric case is also explicitly evaluated.


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