Constraints on a Spin-Dependent Exotic Interaction between Electrons with Single Electron Spin Quantum Sensors

Area of Science:

• Quantum physics
• Particle physics
• Condensed matter physics

Background:

• Investigating exotic interactions beyond the Standard Model is crucial for fundamental physics.
• Nitrogen-vacancy (NV) centers in diamond offer sensitive probes for spin interactions.
• Previous experiments have constrained certain exotic couplings, but further improvements are needed.

Purpose of the Study:

• To establish a new laboratory-derived bound on the axial-vector mediated interaction between electron spins.
• To constrain the exotic electron-electron coupling (g_{A}^{e}g_{A}^{e}) at micrometer scales.
• To assess the potential of NV centers for future searches for new physics.

Main Methods:

• Utilizing single nitrogen-vacancy (NV) centers in diamond as a sensitive detector.
• Employing laser-polarized electron spins from a p-terphenyl doped pentacene-d_{14} crystal as the source.
• Measuring the polarization signal via NV centers to infer interaction strengths.

Main Results:

• A new laboratory bound on axial-vector mediated electron spin interactions was established.
• Constraints were placed on the exotic electron-electron coupling g_{A}^{e}g_{A}^{e} within the 10–900 μm force range.
• An upper bound of |g_{A}^{e}g_{A}^{e}/4πℏc|≤1.8×10^{-19} at 500 μm was achieved, improving previous results by an order of magnitude.

Conclusions:

• Single NV centers provide a powerful platform for probing exotic spin-spin interactions.
• The established bounds significantly advance the search for new particles and forces.
• NV centers demonstrate promise for future experiments targeting physics beyond the Standard Model.