Regular Article - Theoretical Physics
Revisiting the minimum length in the Schwinger–Keldysh formalism
Dipartimento di Fisica e Astronomia, Università di Bologna, Via Irnerio 46, 40126, Bologna, Italy
2 I.N.F.N., Sezione di Bologna, IS-FLAG, Via B. Pichat 6/2, 40127, Bologna, Italy
Accepted: 10 October 2020
Published online: 17 October 2020
The existence of a minimum length in quantum gravity is investigated by computing the in-in expectation value of the proper distance in the Schwinger–Keldysh formalism. No minimum geometrical length is found for arbitrary gravitational theories to all orders in perturbation theory. Using non-perturbative techniques, we also show that neither the conformal sector of general relativity nor higher-derivative gravity features a minimum length. A minimum length scale, on the other hand, seems to always be present when one considers in-out amplitudes, from which one could extract the energy scale of scattering processes.
© The Author(s) 2020
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