Causality, unitarity and stability in quantum gravity: a non-perturbative perspective
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Causality, unitarity and stability in quantum gravity : a non-perturbative perspective. / Platania, Alessia.
In: Journal of High Energy Physics, Vol. 2022, No. 9, 167, 09.2022.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Causality, unitarity and stability in quantum gravity
T2 - a non-perturbative perspective
AU - Platania, Alessia
N1 - Publisher Copyright: © 2022, The Author(s).
PY - 2022/9
Y1 - 2022/9
N2 - Resumming quantum fluctuations at the level of the gravitational path integral is expected to result in non-local effective actions and thus in a non-trivial momentum dependence of the propagator. Which properties the (dressed) graviton propagator has to satisfy and whether they can all be met are key open questions. In this work we present criteria and conditions for the momentum dependence of a graviton propagator which is consistent with unitarity, causality, and stability in a non-perturbative setting. To this end, we revisit several aspects of these conditions, highlighting some caveats and subtleties that got lost in recent discussions, and spelling out others that to our best knowledge have not been studied in detail. We discuss the consequences of these concepts for the properties of the graviton propagator. Finally, we provide examples of propagators satisfying unitarity and causality, while avoiding tachyonic and vacuum instabilities, and allowing for an analytic Wick rotation.
AB - Resumming quantum fluctuations at the level of the gravitational path integral is expected to result in non-local effective actions and thus in a non-trivial momentum dependence of the propagator. Which properties the (dressed) graviton propagator has to satisfy and whether they can all be met are key open questions. In this work we present criteria and conditions for the momentum dependence of a graviton propagator which is consistent with unitarity, causality, and stability in a non-perturbative setting. To this end, we revisit several aspects of these conditions, highlighting some caveats and subtleties that got lost in recent discussions, and spelling out others that to our best knowledge have not been studied in detail. We discuss the consequences of these concepts for the properties of the graviton propagator. Finally, we provide examples of propagators satisfying unitarity and causality, while avoiding tachyonic and vacuum instabilities, and allowing for an analytic Wick rotation.
KW - Effective Field Theories
KW - Nonperturbative Effects
KW - Renormalization and Regularization
KW - Renormalization Group
UR - http://www.scopus.com/inward/record.url?scp=85141084798&partnerID=8YFLogxK
U2 - 10.1007/JHEP09(2022)167
DO - 10.1007/JHEP09(2022)167
M3 - Journal article
AN - SCOPUS:85141084798
VL - 2022
JO - Journal of High Energy Physics (Online)
JF - Journal of High Energy Physics (Online)
SN - 1126-6708
IS - 9
M1 - 167
ER -
ID: 388512933