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 Stark time crystals: Symmetry breaking in space and time

2020 ◽  
Vol 102 (19) ◽  
Author(s):  
A. Kshetrimayum ◽  
J. Eisert ◽  
D. M. Kennes
Keyword(s):  
Symmetry Breaking ◽  
Space And Time ◽  
Time Crystals

scholarly journals The Complex Adaptive Delta-Modulator in Sliding Mode Theory

Entropy ◽  
2020 ◽  
Vol 22 (8) ◽  
pp. 814
Author(s):  
Dhafer Almakhles
Keyword(s):  
Steady State ◽  
Discrete Time ◽  
Sliding Mode ◽  
Stability Conditions ◽  
Mode Theory ◽  
Dynamical Behaviors ◽  
Complex Adaptive ◽  
The Stability ◽  
Parameter Values

In this paper, we consider the stability and various dynamical behaviors of both discrete-time delta modulator (Δ-M) and adaptive Δ-M. The stability constraints and conditions of Δ-M and adaptive Δ-M are derived following the theory of quasi-sliding mode. Furthermore, the periodic behaviors are explored for both the systems with steady-state inputs and certain parameter values. The results derived in this paper are validated using simulated examples which confirms the derived stability conditions and the existence of periodicity.

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 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 Symmetry Breaking in Interacting Ring-Shaped Superflows of Bose–Einstein Condensates

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1312 ◽  
Author(s):  
Artem Oliinyk ◽  
Igor Yatsuta ◽  
Boris Malomed ◽  
Alexander Yakimenko
Keyword(s):  
Symmetry Breaking ◽  
Rotational Symmetry ◽  
Mean Field ◽  
Spontaneous Breaking ◽  
Persistent Currents ◽  
Mean Field Model ◽  
Final State ◽  
Double Ring ◽  
Angular Momenta ◽  
Bose Einstein

We demonstrate that the evolution of superflows in interacting persistent currents of ultracold gases is strongly affected by symmetry breaking of the quantum vortex dynamics. We study counter-propagating superflows in a system of two parallel rings in regimes of weak (a Josephson junction with tunneling through the barrier) and strong (rings merging across a reduced barrier) interactions. For the weakly interacting toroidal Bose–Einstein condensates, formation of rotational fluxons (Josephson vortices) is associated with spontaneous breaking of the rotational symmetry of the tunneling superflows. The influence of a controllable symmetry breaking on the final state of the merging counter-propagating superflows is investigated in the framework of a weakly dissipative mean-field model. It is demonstrated that the population imbalance between the merging flows and the breaking of the underlying rotational symmetry can drive the double-ring system to final states with different angular momenta.

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