Correction: Kantowski–Sachs cosmology, Weyl geometry, and asymptotic safety in quantum gravity

We review and discuss higher derivative and nonlocal theories of quantum gravity focusing on their UV and unitarity properties. We first consider the general fourth-order gravitational action, then actions containing derivatives up to any given fixed order, and discuss their UV divergences, fixed points and concomitant unitarity issues. This leads to a more general discussion of "asymptotic safety" and unitarity, which motivates the introduction of nonlocal theories containing derivatives to all orders arising from the expansion of entire functions. For such theories good UV behavior is visible at any finite truncation, but unitarity emerges only when derivatives to all orders are included.

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Consistency of matter models with asymptotically safe quantum gravity

Canadian Journal of Physics ◽

10.1139/cjp-2014-0574 ◽

2015 ◽

Vol 93 (9) ◽

pp. 988-994 ◽

Cited By ~ 28

Author(s):

Pietro Donà ◽

Astrid Eichhorn ◽

Roberto Percacci

Keyword(s):

Renormalization Group ◽

Standard Model ◽

Quantum Gravity ◽

Degrees Of Freedom ◽

Experimental Tests ◽

Matter Content ◽

Asymptotic Safety ◽

The Standard Model ◽

Renormalization Group Flows ◽

Matter Fields

We discuss the compatibility of quantum gravity with dynamical matter degrees of freedom. Specifically, we present bounds we obtained in Donà et al. (Phys. Rev. D, 89, 084035 (2014) doi:10.1103/PhysRevD.89.084035 ) on the allowed number and type of matter fields within asymptotically safe quantum gravity. As a novel result, we show bounds on the allowed number of spin-3/2 (Rarita–Schwinger) fields (e.g., the gravitino). These bounds, obtained within truncated renormalization group flows, indicate the compatibility of asymptotic safety with the matter fields of the standard model. Further, they suggest that extensions of the matter content of the standard model are severely restricted in asymptotic safety. This means that searches for new particles at colliders could provide experimental tests for this particular approach to quantum gravity.

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