Higher-order and fractional discrete time crystals in clean long-range interacting systems
Andrea Pizzi1, Johannes Knolle2,3,4, Andreas Nunnenkamp5
1Cavendish Laboratory, University of Cambridge, Cambridge, UK.
Nature Communications
|April 21, 2021
Summary
Researchers discovered novel higher-order discrete time crystals in spin-1/2 systems. These systems exhibit surprising integer and fractional periodicities beyond the typical limit, opening new avenues for quantum matter research.
Area of Science:
- Quantum physics
- Condensed matter physics
- Non-equilibrium statistical mechanics
Background:
- Discrete time crystals (DTCs) are periodically driven quantum systems.
- Their response periodicity (nT) is typically an integer n > 1.
- In spin-1/2 systems, n is usually limited to 2, bounded by the Hilbert space dimension.
Purpose of the Study:
- To investigate the possibility of higher-order discrete time crystals beyond the conventional limitations.
- To explore novel phases of matter in spin-1/2 systems with long-range interactions.
- To characterize the stability and properties of these emergent phases.
Main Methods:
- Exact diagonalization
- Semiclassical methods
- Spin-wave approximations
Main Results:
- Demonstrated a clean spin-1/2 system sustaining higher-order DTCs with integer and fractional n > 2.
- Identified a wide variety of emergent non-equilibrium phases.
- Established the stability of these phases against competing long- and short-range interactions.
Conclusions:
- Higher-order discrete time crystals with fractional periodicities are achievable in spin-1/2 systems.
- Long-range interactions and transverse fields are key to realizing these novel phases.
- The findings are relevant for experimental platforms like ultracold atoms and trapped ions.
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