# Boundary Time Crystals.

@article{Iemini2018BoundaryTC, title={Boundary Time Crystals.}, author={Fernando Iemini and Angelo Russomanno and Jonathan Keeling and Marco Schir{\`o} and Marcello Dalmonte and Rosario Fazio}, journal={Physical review letters}, year={2018}, volume={121 3}, pages={ 035301 } }

In this work we introduce boundary time crystals. Here continuous time-translation symmetry breaking occurs only in a macroscopic fraction of a many-body quantum system. After introducing their definition and properties, we analyze in detail a solvable model where an accurate scaling analysis can be performed. The existence of the boundary time crystals is intimately connected to the emergence of a time-periodic steady state in the thermodynamic limit of a many-body open quantum system. We also…

## 100 Citations

Discrete Time Crystals in the Absence of Manifest Symmetries or Disorder in Open Quantum Systems.

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A semiclassical approach reveals the emergence of a robust discrete time-crystalline phase in the thermodynamic limit in which metastability, dissipation, and interparticle interactions play a crucial role.

Exact solution of a boundary time-crystal phase transition: time-translation symmetry breaking and non-Markovian dynamics of correlations

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The breaking of the continuous time-translation symmetry manifests, in Markovian open quantum systems, through the emergence of non-stationary dynamical phases. Systems that display nonequilibrium…

Imaginary Time Crystal of Thermal Quantum Matter

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- 2019

Spontaneous symmetry breaking is responsible for rich quantum phenomena from crystalline structures to superconductivity. This concept was boldly extended to the breaking of time translation, opening…

Dynamical quantum phase transitions in systems with broken continuous time and space translation symmetries

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Spontaneous breaking of continuous time translation symmetry into a discrete one is related to time crystal formation. While the phenomenon is not possible in the ground state of a time-independent…

Classical Many-Body Time Crystals.

- Physics, MedicinePhysical review letters
- 2019

This work provides a simple and pedagogical framework by which to obtain many-body time crystals using parametrically coupled resonators and presents a clear distinction between single-mode time-translation symmetry breaking and a situation where an extensive number of degrees of freedom undergo the transition.

Fractional time crystals

- PhysicsPhysical Review A
- 2019

Time crystals are quantum systems that are able to reveal condensed matter behavior in the time domain. It is known that crystallization in time can be observed in a periodically driven many-body…

Isolated Heisenberg magnet as a quantum time crystal

- Physics
- 2020

Local observables of closed many-body quantum systems are generally believed to quickly equilibrate after a quench, according to the eigenstate thermalization hypothesis. Here, the authors show that…

Classical discrete time crystals

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- 2018

The spontaneous breaking of time-translation symmetry in periodically driven quantum systems leads to a new phase of matter: the discrete time crystal (DTC). This phase exhibits collective…

Ancilla assisted Discrete Time Crystals in Non-interacting Spin Systems

- Physics
- 2021

We show here through experiments and exact analytical models the emergence of discrete time translation symmetry breaking in non-interacting systems. These time-periodic structures become stable…

Time crystals: a review.

- Physics, MedicineReports on progress in physics. Physical Society
- 2018

The struggle to observe discrete time crystals is reviewed here together with propositions that generalize this concept introducing condensed matter like physics in the time domain.

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