One-loop calculations in quantum gravity: Graviton self-energy, perturbative gauge invariance and Slavnov-Ward identities (Q2704297)

Quantum gravity (QG), which is non-renormalizable but fundamentally important, is yet to reach a finally acceptable maturity. Models of varied depths in this connection have been presented and valiant efforts are being made for further elucidation.NEWLINENEWLINENEWLINEIn the paper under review, the one-loop self-energy within the framework of causal perturbation theory is calculated. In the second section the transition from general relativity to perturbative QG in a causal approach is explored and explained. The condition of gauge invariance is presented together with certain related consequences also. In the ensuing section the two-point distribution for graviton self-energy is constructed and the questions of normalization and distribution splitting are dealt with. In section 4 the gravitational Slavnov-Ward identities for the two-point function are verified and their relation to perturbative gauge invariance is discussed. This is followed by a description of fixing of the freedom in the normalization of the self-energy tensor setup and settled. Section 6 is devoted to the corrections to the Newtonian potential due to graviton self-energy. Finally, in the last section, the perturbative gauge invariance to second order for the loop contribution graph sector is exhibited.NEWLINENEWLINENEWLINEThere are four technical appendices given in the end enriching and explaining certain intricate expressions and procedures. In the 34-page work 49 references are cited.