On prethermal time crystals from semi-holography

TL;DR

This paper shows that semi-holographic quantum systems can naturally exhibit prethermal time-crystal behavior with almost dissipationless oscillations, without fine-tuning, and identifies associated instabilities leading to inhomogeneities.

Contribution

It demonstrates the existence of prethermal time-crystals in semi-holographic systems and explores their stability and potential realization in gauge theories.

Findings

Identification of almost dissipationless oscillating modes in semi-holographic systems.

Observation of short wavelength instabilities leading to inhomogeneities.

Evidence that black hole horizons can host metastable time-crystal phases.

Abstract

We demonstrate the existence of a pair of almost dissipationless oscillating modes at low temperatures in both the shear and sound channels of a hybrid quantum system, comprised of a weakly self-interacting perturbative sector coupled to strongly self-interacting holographic degrees of freedom described by a black hole geometry. We argue that these modes realize prethermal time-crystal behavior in semi-holographic systems without fine-tuning and can be observed by measuring operators that probe either the hard (perturbative) or the soft (holographic) sector. We also find novel {short wavelength} instabilities that lead to the formation of inhomogeneities even at higher temperatures. These results provide evidence that black holes with planar horizons and dynamical boundary conditions can develop both inhomogeneous and metastable time-crystal phases over a wide range of temperatures set by an intermediate scale given by the intersector coupling. Furthermore, they suggest that such phases can be realized without external driving in non-Abelian plasmas of asymptotically free gauge theories in the large-$N$ limit.