Emergent discrete space-time crystal of Majorana-like quasiparticles in chiral liquid crystals

TL;DR

This paper reports the discovery of classical analogues of space-time crystals in liquid crystals driven by electrical signals, highlighting topological Majorana-like quasiparticles and their robustness, expanding the concept beyond quantum systems.

Contribution

It introduces classical space-time crystals in liquid crystals with topological Majorana-like quasiparticles, demonstrating symmetry breaking in both time and space in a soft matter system.

Findings

Observation of 1+1D and 2+1D classical space-time crystals.

Presence of topological Majorana-like quasiparticles.

Robustness against temporal and spatial perturbations.

Abstract

Time crystals spontaneously break the time translation symmetry, as recently has been frequently reported in quantum systems. Here we describe the observation of classical analogues of both 1+1-dimensional and 2+1-dimensional discrete space-time crystals in a liquid crystal system driven by a Floquet electrical signal. These classical time crystals comprise particle-like structural features and exists over a wide range of temperatures and electrical driving conditions. The phenomenon-enabling period-doubling effect comes from their topological Majorana-like quasiparticle features, where periodic inter-transformations of co-existing topological solitons and disclinations emerge in response to external stimuli and play pivotal roles. Our discrete space-time crystals exhibit robustness against temporal perturbations and spatial defects, behaving like a time-crystalline analogues of a smectic phase. Our findings show that the simultaneous symmetry breaking in time and space can be a widespread occurrence in numerous open systems, not only in quantum but also in a classical soft matter context.