We discuss the calculation of one-loop effective actions in Lorentzian spacetimes, based on a very simple application of the method of steepest descent to the integral over the field. We show that for static spacetimes this procedure agrees with the analytic continuation of Euclidean calculations. We also discuss how to calculate the effective action by integrating a renormalization group equation. We show that the result is independent of arbitrary choices in the definition of the coarse-graining and we see again that the Lorentzian and Euclidean calculations agree. When applied to quantum gravity on static backgrounds, our procedure is equivalent to analytically continuing time and the integral over the conformal factor.

Quantum fields without wick rotation / Baldazzi, A.; Percacci, R.; Skrinjar, V.. - In: SYMMETRY. - ISSN 2073-8994. - 11:3(2019), pp. 1-16. [10.3390/sym11030373]

Quantum fields without wick rotation

Baldazzi A.;Percacci R.;Skrinjar V.
2019-01-01

Abstract

We discuss the calculation of one-loop effective actions in Lorentzian spacetimes, based on a very simple application of the method of steepest descent to the integral over the field. We show that for static spacetimes this procedure agrees with the analytic continuation of Euclidean calculations. We also discuss how to calculate the effective action by integrating a renormalization group equation. We show that the result is independent of arbitrary choices in the definition of the coarse-graining and we see again that the Lorentzian and Euclidean calculations agree. When applied to quantum gravity on static backgrounds, our procedure is equivalent to analytically continuing time and the integral over the conformal factor.
2019
11
3
1
16
373
https://www.mdpi.com/2073-8994/11/3/373
https://arxiv.org/abs/1901.01891
Baldazzi, A.; Percacci, R.; Skrinjar, V.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/110758
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