Wave function of the universe in the presence of trans-Planckian censorship

TL;DR

This paper explores how incorporating a complex term into the quantum cosmology wave function, consistent with the Trans-Planckian Censorship Conjecture, suppresses universe configurations that violate TCC, affecting inflationary parameters.

Contribution

It introduces a complex-valued modification to the Einstein-Hilbert action that suppresses TCC-violating geometries within the minisuperspace quantum cosmology framework.

Findings

Suppression of TCC-violating universe configurations.

Reduced Hubble rate at the end of inflation.

Implications for primordial power spectrum.

Abstract

The wave function for a closed de Sitter universe has been computed, demanding consistency with the recently proposed Trans-Planckian Censorship Conjecture (TCC). We extend the Einstein-Hilbert action to contain a complex-valued term which provides an exponentially decaying weight for the geometries violating TCC in the Lorentzian path integral sum while working in the minisuperspace approach to quantum cosmology. This \textit{postulated} modification suppresses the probability of evolution of the universe into configurations that violate TCC. We show that due to the presence of this suppression factor, the Hubble rate of the universe at the end of the inflation gets subdued and assumes a value less than what is expected classically. Moreover, the consequences of this quantum gravity motivated correction in the primordial power spectrum are discussed as well.