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 Stroboscopic aliasing in long-range interacting quantum systems

2021 ◽  
Vol 4 (3) ◽  
Author(s):  
Shane Kelly ◽  
Eddy Timmermans ◽  
Jamir Marino ◽  
S.-W. Tsai
Keyword(s):  
Long Range ◽  
Frame Rate ◽  
Reverse Direction ◽  
Entangled State ◽  
Many Body ◽  
Helicopter Blades ◽  
Time Translation ◽  
Potential Applications ◽  
Translation Symmetry ◽  
Many Body Systems

We unveil a mechanism for generating oscillations with arbitrary multiplets of the period of a given external drive, in long-range interacting quantum many-particle spin systems. These oscillations break discrete time translation symmetry as in time crystals, but they are understood via two intertwined stroboscopic effects similar to the aliasing resulting from video taping a single fast rotating helicopter blade. The first effect is similar to a single blade appearing as multiple blades due to a frame rate that is in resonance with the frequency of the helicopter blades' rotation; the second is akin to the optical appearance of the helicopter blades moving in reverse direction. Analogously to other dynamically stabilized states in interacting quantum many-body systems, this stroboscopic aliasing is robust to detuning and excursions from a chosen set of driving parameters, and it offers a novel route for engineering dynamical n-tuplets in long-range quantum simulators, with potential applications to spin squeezing generation and entangled state preparation.

scholarly journals Feynman diagrams and rooted maps

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 149-167 ◽  
Author(s):  
Andrea Prunotto ◽  
Wanda Maria Alberico ◽  
Piotr Czerski
Keyword(s):  
Single Particle ◽  
Feynman Diagram ◽  
Feynman Diagrams ◽  
Topological Properties ◽  
Many Body ◽  
Perturbative Order ◽  
Original Definition ◽  
Many Body Systems ◽  
Definition Of ◽  
Particle Propagator

Abstract The rooted maps theory, a branch of the theory of homology, is shown to be a powerful tool for investigating the topological properties of Feynman diagrams, related to the single particle propagator in the quantum many-body systems. The numerical correspondence between the number of this class of Feynman diagrams as a function of perturbative order and the number of rooted maps as a function of the number of edges is studied. A graphical procedure to associate Feynman diagrams and rooted maps is then stated. Finally, starting from rooted maps principles, an original definition of the genus of a Feynman diagram, which totally differs from the usual one, is given.

THE UNIVERSAL EQUATIONS OF MOTION FOR NONLINEAR FIELDS IN DIFFERENT BASES DESCRIBING STRONGLY INTERACTING MANY-BODY SYSTEMS WITH TWO-BODY INTERACTIONS

1995 ◽  
Vol 09 (13n14) ◽  
pp. 1611-1637 ◽  
Author(s):  
J.M. DIXON ◽  
J.A. TUSZYŃSKI
Keyword(s):  
Plane Wave ◽  
Coherent Structures ◽  
Equations Of Motion ◽  
Quantum Field ◽  
Many Body ◽  
Field Equations ◽  
Strongly Interacting ◽  
Highly Nonlinear ◽  
Many Body Systems ◽  
Definition Of

A brief account of the Method of Coherent Structures (MCS) is presented using a plane-wave basis to define a quantum field. It is also demonstrated that the form of the quantum field equations, obtained by MCS, although highly nonlinear for many-body systems with two-body interactions, is independent of the basis of states used for the definition of the field.

Thermal Gaussian molecular dynamics for quantum dynamics simulations of many-body systems: Application to liquid para-hydrogen

2011 ◽  
Vol 134 (17) ◽  
pp. 174109 ◽  
Author(s):  
Ionuţ Georgescu ◽  
Jason Deckman ◽  
Laura J. Fredrickson ◽  
Vladimir A. Mandelshtam
Keyword(s):  
Molecular Dynamics ◽  
Quantum Dynamics ◽  
Para Hydrogen ◽  
Many Body ◽  
Many Body Systems ◽  
Dynamics Simulations

The definition of the velocity field in many body systems

1969 ◽  
Vol 29 (10) ◽  
pp. 610-611 ◽  
Author(s):  
B.B. Varga ◽  
S.G. Eckstein
Keyword(s):  
Velocity Field ◽  
Many Body ◽  
Many Body Systems ◽  
Definition Of

scholarly journals QUANTUM DYNAMICS WITH AN ENSEMBLE OF HAMILTONIANS

2013 ◽  
Vol 27 (26) ◽  
pp. 1330019 ◽  
Author(s):  
ARMIN RAHMANI
Keyword(s):  
Disordered Systems ◽  
Quantum Dynamics ◽  
Nonequilibrium Dynamics ◽  
Quantum Evolution ◽  
Many Body ◽  
Driven Systems ◽  
Shortcuts To Adiabaticity ◽  
New Directions ◽  
Time Quantum ◽  
Many Body Systems

We review recent progress in the nonequilibrium dynamics of thermally isolated many-body quantum systems, evolving with an ensemble of Hamiltonians as opposed to deterministic evolution with a single time-dependent Hamiltonian. Such questions arise in (i) quantum dynamics of disordered systems, where different realizations of disorder give rise to an ensemble of real-time quantum evolutions, (ii) quantum evolution with noisy Hamiltonians (temporal disorder), which leads to stochastic Schrödinger equations, and, (iii) in the broader context of quantum optimal control, where one needs to analyze an ensemble of permissible protocols in order to find one that optimizes a given figure of merit. The theme of ensemble quantum evolution appears in several emerging new directions in noneqilibrium quantum dynamics of thermally isolated many-body systems, which include many-body localization, noise-driven systems, and shortcuts to adiabaticity.

scholarly journals Spontaneous breaking of a discrete time-translation symmetry

2021 ◽  
Vol 104 (2) ◽  
Author(s):  
J. Smits ◽  
H. T. C. Stoof ◽  
P. van der Straten
Keyword(s):  
Discrete Time ◽  
Spontaneous Breaking ◽  
Time Translation ◽  
Translation Symmetry
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