



01396nas a2200157   4500008004100000245006600041210006600107260001500173300001100188490000600199520092600205100002601131700001901157700002501176856003701201       2018                        eng d00aStructure of Correlated Worldline Theories of Quantum Gravity0 aStructure of Correlated Worldline Theories of Quantum Gravity  c2018/06/21  a0840520 vD3 a<p>We consider the general form of &quot;Correlated Worldline&quot; (CWL) theories of quantum gravity. We show that one can have 2 different kinds of CWL theory, in which the generating functional is written as either a sum or a product over multiple copies of the coupled matter and gravitational fields. In both versions, the paths in a functional formulation are correlated via gravity itself, causing a breakdown of the superposition principle; however, the product form survives consistency tests not satisfied by the summed form. To better understand the structure of these two theories, we show how to perform diagrammatic expansions in the gravitational coupling for each version of CWL theory, using particle propagation and scalar fields as examples. We explicitly calculate contributions to 2-point and 4-point functions, again for each version of the theory, up to 2nd-order in the gravitational coupling.</p>1 aBarvinsky, Andrei, O.1 aCarney, Daniel1 aStamp, Philip, C. E.  uhttps://arxiv.org/abs/1806.08043