.png){kind=icon}
.png){kind=icon}
Return
Microcausality without Lorentz invariance
.png){kind=icon}
OA
AI
DOI：10.1007/JHEP07(2025)188.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
Microcausality — the vanishing of commutators outside the lightcone — is a fundamental property of relativistic quantum field theories. We derive its implications for two-point functions of scalar operators on Lorentz-breaking states. We restrict to spatially homogeneous and isotropic states, at zero and finite temperature, such as finite-density states of matter and primordial inflationary states. In a mixed (t, $$ \overrightarrow{k} $$ ) representation, we find certain analyticity and exponential boundedness conditions, which we verify in a variety of examples. Crucially, we discuss how our conditions can be tested within the regime of validity of Lorentz-breaking low-energy effective field theories, clarifying the role of the group velocity of low-energy excitations. In the cosmological case, we derive a positivity condition on an EFT coefficient in an inflationary background. Lastly, we comment on how microcausality can be used to constrain higher-point correlation functions, via suitable nested commutators.
Journal
IF:
5.5
Papers:
3.9W
Citations:
13.7W
