Seeking the loop quantum gravity Barbero-Immirzi parameter and field in 4D, N=1 supergravity

Journal Article · Tue Sep 15 04:00:00 EDT 2009 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.80.065003· OSTI ID:21322760

Gates, Jr, S James ^[1]; Ketov, Sergei V ^[2]; Yunes, Nicolas ^[3]

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1. Center for String and Particle Theory, Department of Physics, University of Maryland, College Park, Maryland 20742-4111 (United States)
2. Department of Physics, Tokyo Metropolitan University, Minami-ohsawa 1-1, Hachioji-shi, Tokyo 192-0397 (Japan)
3. Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States)

We embed the loop quantum gravity Barbero-Immirzi parameter and field within an action describing 4D, N=1 supergravity and thus within a low-energy effective action of superstring/M theory. We use the fully gauge-covariant description of supergravity in (curved) superspace. The gravitational constant is replaced with the vacuum expectation value of a scalar field, which in local supersymmetry is promoted to a complex, covariantly chiral scalar superfield. The imaginary part of this superfield couples to a supersymmetric Holst term. The Holst term also serves as a starting point in the loop quantum gravity action. This suggest the possibility of a relation between loop quantum gravity and supersymmetric string theory, where the Barbero-Immirzi parameter and field of the former play the role of the supersymmetric axion in the latter. Adding matter fermions in loop quantum gravity may require the extension of the Holst action through the Nieh-Yan topological invariant, while in pure, matter-free supergravity their supersymmetric extensions are the same. We show that, when the Barbero-Immirzi parameter is promoted to a field in the context of 4D supergravity, it is equivalent to adding a dynamical complex chiral (dilaton-axion) superfield with a nontrivial kinetic term (or Kaehler potential), coupled to supergravity.

• OSTI ID: 21322760
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 6 Vol. 80; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CHIRALITY
FERMIONS
GAUGE INVARIANCE
M-THEORY
POTENTIALS
QUANTUM GRAVITY
SCALAR FIELDS
STRING THEORY
SUPERGRAVITY
SUPERSTRING MODELS
SUPERSYMMETRY
TOPOLOGY