Sensing with discrete time crystals

Area of Science:

• Quantum physics and condensed matter.
• Exploration of non-equilibrium states of matter.

Background:

• Prethermal discrete time crystals exhibit long-range spatiotemporal order and subharmonic response.
• Their robustness to drive protocol perturbations makes them suitable for quantum sensing.
• Sensitivity to order parameter deviations is key for precise measurements.

Purpose of the Study:

• To implement frequency-selective detection of time-varying magnetic fields.
• To utilize prethermal discrete time crystal order for magnetic field sensing.
• To demonstrate a novel quantum sensing application in a specific spin system.

Main Methods:

• Utilized a system of strongly driven, dipolar-coupled ¹³C nuclear spins in diamond.
• Exploited the sensitivity of prethermal discrete time crystal order to magnetic field perturbations.
• Incorporated an oscillating magnetic field into the time crystal dynamics to observe resonant response.

Main Results:

• Achieved frequency-selective detection of time-varying magnetic fields.
• Observed a sharp resonant response in the order parameter, extending the time crystal lifetime.
• Demonstrated competitive sensitivity in the 0.5-50-kHz range, a challenging frequency band.

Conclusions:

• Prethermal discrete time crystals can be effectively used as quantum sensors for magnetic fields.
• The demonstrated sensing principle is robust to drive errors and sample inhomogeneities.
• The approach is applicable to various quantum platforms, including superconducting circuits, neutral atoms, and trapped ions.