# Quantum Time Crystal By Decoherence: Proposal With Incommensurate Charge Density Wave Ring

## TL;DR

This paper proposes a model where a macroscopic quantum ring with incommensurate charge density wave, coupled to an environment, exhibits periodic oscillations in charge density, effectively breaking time translation symmetry and forming a metastable quantum time crystal.

## Contribution

It introduces a novel model of a quantum time crystal using a decoherence framework with an incommensurate charge density wave ring, distinct from Floquet time crystals.

## Key findings

- Charge density oscillates periodically due to decoherence.
- The model forms a metastable quantum time crystal.
- Hamiltonian remains time-independent, unlike Floquet systems.

## Abstract

We show that time translation symmetry of a ring system with a macroscopic quantum ground state is broken by decoherence. In particular, we consider a ring-shaped incommensurate charge density wave (ICDW ring) threaded by a fluctuating magnetic flux: the Caldeira-Leggett model is used to model the fluctuating flux as a bath of harmonic oscillators. We show that the charge density expectation value of a quantized ICDW ring coupled to its environment oscillates periodically. The Hamiltonians considered in this model are time independent unlike "Floquet time crystals" considered recently. Our model forms a metastable quantum time crystal with a finite length in space and in time.