Effective gauge group of pure loop quantum gravity is SO(3): New estimate of the Immirzi parameter
arXiv:gr-qc/0511084 · doi:10.1016/j.physletb.2006.04.028
Abstract
We argue that the effective gauge group for {\it pure} four-dimensional loop quantum gravity(LQG) is SO(3) (or ) instead of SU(2) (or ). As a result, links with half-integer spins in spin network states are not realized for {\it pure} LQG, implying a modification of the spectra of area and volume operators. Our observations imply a new value of for the Immirzi parameter which is obtained from matching the Bekenstein-Hawking entropy to the number of states from LQG calculations. Moreover, even if the dominant contribution to the entropy is not assumed to come from configurations with the minimum spins, the results of both pure LQG and the supersymmetric extension of LQG can be made compatible when only integer spins are realized for the former, while the latter also contains half-integer spins, together with an Immirzi parameter for the supersymmetric case which is twice the value of the SO(3) theory. We also verify that the coefficient of logarithmic correction to the Bekenstein-Hawking entropy formula is robust, independent of whether only integer, or also half-integer spins, are realized.
new value of Immirzi parameter is ~0.170; dominance of miminum spin configurations is not assumed in comparing with Bekenstein-Hawking formula; typos corrected. Version pressed in PLB
References in corpus (9)
- Black hole entropy in Loop Quantum Gravity
- Hawking Radiation and Black Hole Thermodynamics
- Quasinormal Modes, the Area Spectrum, and Black Hole Entropy
- Black hole entropy from Quantum Geometry
- Gravity and the Quantum
- An improved estimate of black hole entropy in the quantum geometry approach
- Quasinormal modes prefer supersymmetry ?
- Ambiguity of black hole entropy in loop quantum gravity
- Origin of the Immirzi Parameter