# Universal Prethermal Dynamics in Gross-Neveu-Yukawa Criticality

## TL;DR

This paper investigates the universal prethermal dynamics near a quantum critical point in the Gross-Neveu-Yukawa model, revealing two fixed points and unique fermionic signatures, with potential experimental implications.

## Contribution

It identifies a new non-thermal fixed point in fermionic systems and characterizes the crossover between different prethermal scaling regimes.

## Key findings

- Discovery of a non-thermal fixed point unique to fermionic fields.
- Negative initial slip exponent for multiple fermion flavors.
- Temporal crossover between two universal prethermal regimes.

## Abstract

We study the prethermal dynamics of the Gross-Neveu-Yukawa quantum field theory, suddenly quenched in the vicinity of a quantum critical point. We find that the universal prethermal dynamics is controlled by two fixed points depending on the size of the quench. Besides the usual equilibrium chiral Ising fixed point for a shallow quench, a dynamical chiral Ising fixed point is identified for a deep quench. Intriguingly, the latter is a non-thermal fixed point without any equilibrium counterpart due to the participation of gapless fermionic fields. We also find that in the scaling regime controlled by the equilibrium fixed point, the initial slip exponent is rendered negative if there are enough flavors of fermions, thus providing a unique signature of fermionic prethermal dynamics. We then explore the temporal crossover between the universal scaling regimes governed by the two universality classes. Possible experimental realizations are also discussed.