Edholm, James (2018) Conditions for defocusing around more general metrics in infinite derivative gravity. Physical Review D, 97 (8): 084046. ISSN 1550-7998
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Abstract
Infinite derivative gravity is able to resolve the big bang curvature singularity present in general relativity by using a simplifying ansatz. We show that it can also avoid the Hawking-Penrose singularity, by allowing defocusing of null rays through the Raychaudhuri equation. This occurs not only in the minimal case where we ignore the matter contribution but also in the case where matter plays a key role. We investigate the conditions for defocusing for the general case where this ansatz applies and also for more specific metrics, including a general Friedmann-Robertson-Walker metric and three specific choices of the scale factor which produce a bouncing Friedmann-Robertson-Walker universe.