# Do we Come from a Quantum Anomaly?

## TL;DR

This paper proposes a string theory-based cosmological model where gravitational anomalies during inflation influence vacuum energy, leading to baryogenesis, dark energy, and axion dark matter, with implications for the universe's evolution.

## Contribution

It introduces a novel string-inspired framework linking gravitational anomalies to cosmological phenomena like baryogenesis and dark energy.

## Key findings

- Vacuum energy density runs with H^2 during inflation.
- Baryogenesis occurs via leptogenesis with right-handed neutrinos.
- Dark energy is mildly dynamical and dark matter consists of axions.

## Abstract

We present a string-based picture of the cosmological evolution in which (CP-violating) gravitational anomalies acting during the inflationary phase of the universe cause the vacuum energy density to "run" with the effective Hubble parameter squared, $H^2$, thanks to the axion field of the bosonic string multiplet. This leads to baryogenesis through leptogenesis with massive right-handed neutrinos. The generation of chiral matter after inflation helps in cancelling the anomalies in the observable radiation- and matter- dominated eras. The present era inherits the same "running vacuum" structure triggered during the inflationary time by the axion field. The current dark energy is thus predicted to be mildly dynamical, and dark matter should be made of axions. Paraphrasing Carl Sagan: "we are all anomalously made from starstuff " .