The way to the Big Bang
Victor Berezin, Inna Ivanova, Anastasia Kuprina
TL;DR
This paper advances a conformally invariant, phenomenological approach to cosmological particle production from vacuum fluctuations, using induced gravity and an ideal-fluid action to address back-reaction. By reformulating the dynamics in conformal variables, it shows that particle creation cannot occur from classical vacua and must originate from a quantum vacuum at $a=0$, with the transition surface being light-like. The authors classify vacua, derive matching conditions across phase transitions, and introduce gravitating mirages $F_1(x)\varphi^4$ that can mimic dark matter, arguing that the Big Bang can be viewed as a detonation wave propagating through quantum vacuum at light speed in an open universe ($k=0$ or $-1$). The framework yields explicit forms for the production functions $F$ and $F_1$ and presents a self-consistent picture in which cosmological particle creation is tied to conformal invariance and back-reaction effects, with potential observational implications. Overall, the work provides a novel mechanism for early-Universe particle production on a light-like hypersurface and highlights open-Universe dynamics as essential to the proposed scenario.
Abstract
We propose conformal invariance as a fundamental symmetry governing cosmological particle creation from vacuum fluctuations, employing a phenomenological approach with an ideal fluid action to address the long-standing back-reaction problem. We demonstrate that particle production cannot emerge from classical vacua but must originate from a quantum vacuum at zero scale factor, with the transition surface constituting a light-like rather than space-like hypersurface. This implies that particles are created on the light cone and remain causally connected, with their apparent simultaneity being illusory. Our model requires an open Universe ($k=0, -1$) and reconceptualizes the Big Bang as a detonation wave propagating through quantum vacuum at the speed of light.