Spin counting via projection noise measurement of mesoscopic solid-state spin ensemble

• URL: http://arxiv.org/abs/2606.14437v1
• Date: Fri, 12 Jun 2026 13:18:52 GMT
• Title: Spin counting via projection noise measurement of mesoscopic solid-state spin ensemble
• Abstract summary: We report direct measurement of the quantum projection noise of mesoscopic ensembles of nitrogen-vacancy (NV) spin defects at room temperature.<n>We use our protocol to demonstrate projection noise measurements and spin counting from nanoscale NV ensembles of up to 43 spins.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Quantum projection noise is the fundamental noise source for the population measurement of spin ensembles. While projection-noise-limited measurements have been extensively studied in atomic systems, corresponding experiments on solid-state spin ensembles remain challenging due to dominant classical readout noise. Here, we report direct measurement of the quantum projection noise of mesoscopic ensembles of nitrogen-vacancy (NV) spin defects at room temperature. Our experiment is enabled by a high optically-detected magnetic resonance (ODMR) contrast of over 20% for a single crystallographic orientation of the defect spins, obtained by combining polarization-selective optical excitation with spin-to-charge conversion. We use our protocol to demonstrate projection noise measurements and spin counting from nanoscale NV ensembles of up to 43 spins. We further demonstrate that the protocol allows for significant gains in sensitivity for magnetometry applications without need for cryogenic operation or high bias magnetic fields.

Related papers

• Detecting quantum noise of a solid-state spin ensemble with dispersive measurement [0.0]
  We study dispersive readout of an inhomogeneously broadened spin ensemble via coupling to a driven resonator measured via homodyne detection.<n>By studying fluctuations of the measurement record in detail, we also propose an experimental protocol for directly detecting spin squeezing.
  arXiv  Detail & Related papers  (2026-02-03T16:55:03Z)
• Readout of a solid state spin ensemble at the projection noise limit [0.0]
  We demonstrate a direct, quantum non-demolition readout of a mesoscopic ensemble of nitrogen-vacancy centers in diamond.<n>By stabilizing the $14$N nuclear spin bath at high magnetic fields, we achieve a noise reduction of 3.8 dB below the thermal projection noise level.<n>Our results establish projection noise-limited readout as a practical tool for solid-state quantum sensors.
  arXiv  Detail & Related papers  (2025-09-15T12:32:13Z)
• Spin Squeezing of Macroscopic Nuclear Spin Ensembles [44.99833362998488]
  Squeezing macroscopic spin ensembles may prove to be a useful technique for fundamental physics experiments.<n>We analyze the squeezing dynamics in the presence of decoherence and finite spin polarization, showing that achieving 7 dB spin squeezing is feasible in several nuclear spin systems.
  arXiv  Detail & Related papers  (2025-02-19T21:16:54Z)
• First Sub-MeV Dark Matter Search with the QROCODILE Experiment Using Superconducting Nanowire Single-Photon Detectors [51.550188330599525]
  We present the first results from the Quantum Resolution-d Cryogenic Observatory for Dark matter Incident at Low Energy (QROCODILE)<n>The QROCODILE experiment uses a microwire-based superconducting nanowire single-photon detector (SNSPD) as a target and sensor for dark matter scattering and absorption.<n>We report new world-leading constraints on the interactions of sub-MeV dark matter particles with masses as low as 30 keV.
  arXiv  Detail & Related papers  (2024-12-20T19:00:00Z)
• All-optical magnetic imaging with spin defects in van der Waals materials at Angstrom-scale [7.175794024984359]
  We propose a novel magnetic imaging protocol that achieves Angstrom-scale resolution. We combine spin defects in van der Waals materials and terahertz scattering scanning near-field optical microscopy. Our proposed all-optical magnetic imaging protocol holds significant promise for investigating magnetic textures in condensed matter physics.
  arXiv  Detail & Related papers  (2024-11-14T15:28:51Z)
• Spin projection noise and the magnetic sensitivity of optically pumped magnetometers [0.0]
  We present a new approach for calculating the spin projection noise (SPN)-limited signal to noise ratio (SNR) and the magnetic sensitivity of OPMs. Our model is based solely on the mean-field density matrix dynamics. We report on a new SERF feature; the reduction of spin-projection noise at the spin precession frequency as a consequence of strongly-correlated hyperfine spins.
  arXiv  Detail & Related papers  (2024-02-16T15:11:46Z)
• All-Optical Nuclear Quantum Sensing using Nitrogen-Vacancy Centers in Diamond [52.77024349608834]
  Microwave or radio-frequency driving poses a significant limitation for miniaturization, energy-efficiency and non-invasiveness of quantum sensors. We overcome this limitation by demonstrating a purely optical approach to coherent quantum sensing. Our results pave the way for highly compact quantum sensors to be employed for magnetometry or gyroscopy applications.
  arXiv  Detail & Related papers  (2022-12-14T08:34:11Z)
• Toward deep-learning-assisted spectrally-resolved imaging of magnetic noise [52.77024349608834]
  We implement a deep neural network to efficiently reconstruct the spectral density of the underlying fluctuating magnetic field. These results create opportunities for the application of machine-learning methods to color-center-based nanoscale sensing and imaging.
  arXiv  Detail & Related papers  (2022-08-01T19:18:26Z)
• Probing dynamics of a two-dimensional dipolar spin ensemble using single qubit sensor [62.997667081978825]
  We experimentally investigate individual spin dynamics in a two-dimensional ensemble of electron spins on the surface of a diamond crystal. We show that this anomalously slow relaxation rate is due to the presence of strong dynamical disorder. Our work paves the way towards microscopic study and control of quantum thermalization in strongly interacting disordered spin ensembles.
  arXiv  Detail & Related papers  (2022-07-21T18:00:17Z)
• Measuring the magnon-photon coupling in shaped ferromagnets: tuning of the resonance frequency [50.591267188664666]
  cavity photons and ferromagnetic spins excitations can exchange information coherently in hybrid architectures. Speed enhancement is usually achieved by optimizing the geometry of the electromagnetic cavity. We show that the geometry of the ferromagnet plays also an important role, by setting the fundamental frequency of the magnonic resonator.
  arXiv  Detail & Related papers  (2022-07-08T11:28:31Z)
• Quantum sensitivity limits of nuclear magnetic resonance experiments searching for new fundamental physics [91.6474995587871]
  Nuclear magnetic resonance is a promising experimental approach to search for ultra-light axion-like dark matter. We consider a circuit model of a magnetic resonance experiment and quantify three noise sources: spin-projection noise, thermal noise, and amplifier noise.
  arXiv  Detail & Related papers  (2021-03-10T19:00:02Z)
• Spin noise spectroscopy of a noise-squeezed atomic state [0.0]
  We study spin fluctuations of room-temperature neutral atoms in a Bell-Bloom type magnetometer. Results reveal a strong asymmetry in the noise distribution of the atomic signal quadratures at the magnetic resonance.
  arXiv  Detail & Related papers  (2020-12-23T11:59:39Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.