# A comment on"Discrete time crystals: rigidity, criticality, and realizations"

@inproceedings{Khemani2021ACO, title={A comment on"Discrete time crystals: rigidity, criticality, and realizations"}, author={Vedika Khemani and Roderich Moessner and S. L. Sondhi}, year={2021} }

The Letter by N. Y. Yao et. al. [1, 2] presents three models for realizing a many-body localized discrete time-crystal (MBL DTC): a short-ranged model [1], its revised version [2], as well as a long-range model of a trapped ion experiment [1, 3]. We show that none of these realize an MBL DTC for the parameter ranges quoted in Refs. [1, 2]. The central phase diagrams in [1] therefore cannot be reproduced. The models show rapid decay of oscillations from generic initial states, in sharp contrast…

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Reply to Comment on"Discrete Time Crystals: Rigidity Criticality and Realizations"

- Physics
- 2021

This is a reply to the comment from Khemani, Moessner and Sondhi (KMS) [arXiv:2109.00551] on our manuscript [Phys. Rev. Lett. 118, 030401 (2017)]. The main new claim in KMS is that the short-ranged…

## References

SHOWING 1-10 OF 36 REFERENCES

Discrete Time Crystals: Rigidity, Criticality, and Realizations.

- PhysicsPhysical review letters
- 2017

A simple model for a one-dimensional discrete time crystal which explicitly reveals the rigidity of the emergent oscillations as the drive is varied is considered and a blueprint based upon a one dimensional chain of trapped ions is proposed.

A Brief History of Time Crystals.

- Physics
- 2019

The idea of breaking time-translation symmetry has fascinated humanity at least since ancient proposals of the perpetuum mobile. Unlike the breaking of other symmetries, such as spatial translation…

Observation of discrete time-crystalline order in a disordered dipolar many-body system

- PhysicsNature
- 2017

This work observes long-lived temporal correlations, experimentally identifies the phase boundary and finds that the temporal order is protected by strong interactions, which opens the door to exploring dynamical phases of matter and controlling interacting, disordered many-body systems.

Observation of a discrete time crystal

- PhysicsNature
- 2017

The experimental observation of a discrete time crystal, in an interacting spin chain of trapped atomic ions, is presented, which opens the door to the study of systems with long-range spatio-temporal correlations and novel phases of matter that emerge under intrinsically non-equilibrium conditions.

Time-crystalline eigenstate order on a quantum processor

- PhysicsNature
- 2021

Quantum many-body systems display rich phase structure in their low-temperature equilibrium states1. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that…

Realizing discrete time crystal in an one-dimensional superconducting qubit chain

- Physics
- 2021

Floquet engineering, i.e. driving the system with periodic Hamiltonians, not only provides great flexibility in analog quantum simulation, but also supports phase structures of great richness. It has…

Prethermal strong zero modes and topological qubits

- Physics
- 2017

We prove that quantum information encoded in some topological excitations, including certain Majorana zero modes, is protected in closed systems for a time scale exponentially long in system…

Many-body–localized discrete time crystal with a programmable spin-based quantum simulator

- PhysicsScience
- 2021

The results are consistent with the realization of an out-of-equilibrium Floquet phase of matter and introduce a programmable quantum simulator based on solid-state spins for exploring many-body physics.

Stability and instability towards delocalization in many-body localization systems

- Physics
- 2017

We propose a theory that describes quantitatively the (in)stability of fully many-body localization (MBL) systems due to ergodic, i.e., delocalized, grains, that can be, for example, due to disorder…

Simulating a discrete time crystal over 57 qubits on a quantum computer

- Physics
- 2021

We simulate the dynamics of a spin-1/2 chain with nearest neighbor Ising interactions, quenched disorder and periodic driving over 57 qubits on a current quantum computer. A transition between time…