scholarly journals Quantum repetition codes as building blocks of large-period discrete time crystals

2021 ◽  
Vol 104 (18) ◽  
Author(s):  
Raditya Weda Bomantara
Keyword(s):  
Discrete Time ◽  
Building Blocks ◽  
Large Period ◽  
Time Crystals

scholarly journals Stochastic Discrete Time Crystals: Entropy Production and Subharmonic Synchronization

2021 ◽  
Vol 126 (2) ◽  
Author(s):  
Lukas Oberreiter ◽  
Udo Seifert ◽  
Andre C. Barato
Keyword(s):  
Entropy Production ◽  
Discrete Time ◽  
Time Crystals

scholarly journals Discrete Time Crystals: Rigidity, Criticality, and Realizations

2017 ◽  
Vol 118 (3) ◽  
Author(s):  
N. Y. Yao ◽  
A. C. Potter ◽  
I.-D. Potirniche ◽  
A. Vishwanath
Keyword(s):  
Discrete Time ◽  
Time Crystals

Discrete-time Inversion Model Control of a Double-damper System with Uncertain Parameters

2017 ◽  
Vol 6 (3) ◽  
pp. 168
Author(s):  
Marwa Hannachi ◽  
Ikbel Bencheikh Ahmed ◽  
Dhaou Soudani
Keyword(s):  
Discrete Time ◽  
Algebraic Approach ◽  
Building Blocks ◽  
Internal Model Control ◽  
Linear Matrix ◽  
Stability Conditions ◽  
Time Inversion ◽  
Time Model ◽  
Model Control ◽  
The Stability

<span>This paper addresses the control at discrete time of physical complex systems multi-inputs multi-outputs with variables parameters. Classified among the robust control laws the Internal Model Control (IMC) is adopted in this work to ensure the desired performances adjacent to the complexities of the system. However, the application of this control strategy requires that these different building blocks be open loop stable, which invites us, on the one hand, to apply the algebraic approach of Kharitinov for delimiting the summits stability domain’s system. On the other case, the Linear Matrix Inequalities (LMI) approach is applied to determine the corrector’s stability conditions obtained by a specific inversion of the chosen model. It is in this sense that we contribute by this work to execute the command by inversion the discrete-time model in order to ensure the stability and to maintain the performances the stability conditions of required for the double damper system with variable parameters.</span>

Discrete Time Crystals

2020 ◽  
Vol 11 (1) ◽  
pp. 467-499 ◽  
Author(s):  
Dominic V. Else ◽  
Christopher Monroe ◽  
Chetan Nayak ◽  
Norman Y. Yao
Keyword(s):  
Discrete Time ◽  
Quantum Dynamics ◽  
Many Body ◽  
Time Translation ◽  
Translation Symmetry ◽  
Interesting Class ◽  
Many Body Systems ◽  
Definition Of ◽  
Many Body Interactions ◽  
Time Crystals

Experimental advances have allowed for the exploration of nearly isolated quantum many-body systems whose coupling to an external bath is very weak. A particularly interesting class of such systems is those that do not thermalize under their own isolated quantum dynamics. In this review, we highlight the possibility for such systems to exhibit new nonequilibrium phases of matter. In particular, we focus on discrete time crystals, which are many-body phases of matter characterized by a spontaneously broken discrete time-translation symmetry. We give a definition of discrete time crystals from several points of view, emphasizing that they are a nonequilibrium phenomenon that is stabilized by many-body interactions, with no analog in noninteracting systems. We explain the theory behind several proposed models of discrete time crystals, and compare several recent realizations, in different experimental contexts.

scholarly journals Erratum: Discrete Time Crystals: Rigidity, Criticality, and Realizations [Phys. Rev. Lett. 118 , 030401 (2017)]

2017 ◽  
Vol 118 (26) ◽  
Author(s):  
N. Y. Yao ◽  
A. C. Potter ◽  
I.-D. Potirniche ◽  
A. Vishwanath
Keyword(s):  
Discrete Time ◽  
Time Crystals

scholarly journals Spatial-Translation-Induced Discrete Time Crystals

2018 ◽  
Vol 121 (9) ◽  
Author(s):  
Kaoru Mizuta ◽  
Kazuaki Takasan ◽  
Masaya Nakagawa ◽  
Norio Kawakami
Keyword(s):  
Discrete Time ◽  
Spatial Translation ◽  
Time Crystals

scholarly journals Discrete time crystals in Bose-Einstein condensates and the symmetry-breaking edge in a simple two-mode theory

2021 ◽  
Vol 104 (5) ◽  
Author(s):  
Jia Wang ◽  
Krzysztof Sacha ◽  
Peter Hannaford ◽  
Bryan J. Dalton
Keyword(s):  
Symmetry Breaking ◽  
Discrete Time ◽  
Mode Theory ◽  
Bose Einstein ◽  
Time Crystals

scholarly journals Observation of a Floquet symmetry-protected topological phase with superconducting qubits

2021 ◽  
Author(s):  
Dong-Ling Deng ◽  
Xu Zhang ◽  
Wenjie Jiang ◽  
Jinfeng Deng ◽  
Ke Wang ◽  
...  
Keyword(s):  
Discrete Time ◽  
Distinct Type ◽  
Superconducting Qubits ◽  
Nitrogen Vacancy ◽  
Spontaneous Breaking ◽  
Translational Symmetry ◽  
Topological Phase ◽  
Symmetry Protected ◽  
Non Equilibrium ◽  
Time Crystals

Abstract Quantum many-body systems away from equilibrium host a rich variety of exotic phenomena that are forbidden by equilibrium thermodynamics. A prominent example is that of discrete time crystals [1-8], where time translational symmetry is spontaneously broken in periodically driven systems. Pioneering experiments have observed signatures of time crystalline phases with trapped ions [9,10], spins in nitrogen-vacancy centers [11-13], ultracold atoms [14,15], solid spin ensembles [16,17], and superconducting qubits [18-20]. Here, we report the observation of a distinct type of intrinsically non-equilibrium state of matter, a Floquet symmetry-protected topological phase, which is implemented through digital quantum simulation with an array of programmable superconducting qubits. Unlike the discrete time crystals reported in previous experiments, where spontaneous breaking of the discrete time translational symmetry occurs for local observables throughout the whole system, the Floquet symmetry-protected topological phase observed in our experiment breaks the time translational symmetry only at the boundaries and has trivial dynamics in the bulk. More concretely, we observe robust long-lived temporal correlations and sub-harmonic temporal response for the edge spins over up to 40 driving cycles using a circuit whose depth exceeds 240. We demonstrate that the sub-harmonic response is independent of whether the initial states are random product states or symmetry-protected topological states, and experimentally map out the phase boundary between the time crystalline and thermal phases. Our work paves the way to exploring novel non-equilibrium phases of matter emerging from the interplay between topology and localization as well as periodic driving, with current noisy intermediate-scale quantum processors [21].

scholarly journals Period- n Discrete Time Crystals and Quasicrystals with Ultracold Bosons

2019 ◽  
Vol 123 (15) ◽  
Author(s):  
Andrea Pizzi ◽  
Johannes Knolle ◽  
Andreas Nunnenkamp
Keyword(s):  
Discrete Time ◽  
Time Crystals
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