RQC Colloquium

29th RQC Colloquium

• Speaker

  Dr. Emmanuel Flurin
  (CEA-Saclay)

• Date

  16:00-17:00 (JST), December 10, 2024 (Tuesday)

• Venue

  Hybrid(Zoom・Wako C00 Administrative HQ Building, 2F Large Meeting Room)

• Title

  Single Atom Magnetic Resonance by Microwave Photon Counting

• Inquiries

  rqc_colloquium_inquiry[at]ml.riken.jp

• Registration Form

  https://krs2.riken.jp/m/rqc_registration_form

Abstract
Electron spin resonance (ESR) spectroscopy is a widely used technique for characterizing paramagnetic impurities, with applications ranging from chemistry to quantum computing. However, it is typically limited to ensemble-averaged measurements due to its restricted signal-to-noise ratio. Sensitivity sufficient to detect single electron spins has been achieved through methods such as spin-dependent photoluminescence, transport measurements, and scanning probes. Unfortunately, these techniques are often system-specific or sensitive to a small detection volume, leaving practical single-spin detection an ongoing challenge. Here, we demonstrate single-electron magnetic resonance via spin fluorescence detection [1], utilizing a microwave photon counter based on a superconducting transmon qubit operating at millikelvin temperatures. In our experiment, individual paramagnetic erbium ions in a scheelite CaWO4 crystal are manipulated and read out, enabled by magnetic coupling with a small-mode-volume, high-quality-factor superconducting microwave resonator. Leveraging this capability, we perform nuclear magnetic resonance of the nearby 183W nucleus [2], achieving single-shot nuclear spin readout and demonstrating second-scale coherence times for individual atoms. This quantum control over individual high-coherence nuclei opens new avenues for quantum computing. Our method, applicable to arbitrary paramagnetic species with sufficiently long non-radiative relaxation times, enables large detection volumes (~10 μm3), paving the way for ESR at the single-molecule level with unprecedented sensitivity and spectral resolution.

[1] Z. Wang et al., Nature 619, 276–281 (2023).
[2] J. Travesedo et al., arXiv:2408.14282
Flyer: 29th RQC Colloquium Flyer