Related Experiment Video
Updated: May 6, 2026
09:00
Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
9.3K
Readout of a solid state spin ensemble at the projection noise limit
Rouven Maier1,2, Cheng-I Ho1,3, Andrej Denisenko1
13rd Institute of Physics, University of Stuttgart, Stuttgart, Germany.
Nature Communications
|May 4, 2026
Summary
Researchers achieved quantum non-demolition readout for spin ensembles, surpassing the photon shot-noise limit. This breakthrough in quantum sensing brings solid-state devices closer to the fundamental spin projection noise limit.
Area of Science:
- Quantum Science and Technology
- Solid-State Physics
- Quantum Sensing
Background:
- Spin ensembles are crucial for quantum science applications, including quantum sensing and spectroscopy.
- Current solid-state implementations are limited by photon shot noise, exceeding the standard quantum limit set by spin projection noise.
Purpose of the Study:
- To demonstrate a quantum non-demolition readout for mesoscopic spin ensembles that overcomes the photon shot-noise limitation.
- To approach the intrinsic spin projection noise limit in solid-state quantum sensors.
Main Methods:
- Utilized a mesoscopic ensemble of nitrogen-vacancy (NV) centers in diamond.
- Stabilized the intrinsic 14N nuclear spin bath at high magnetic fields.
- Employed a repetitive nuclear-assisted spin readout technique.
Main Results:
- Achieved a quantum non-demolition readout surpassing the photon shot-noise limit.
- Reduced noise by 3.8 dB below the thermal projection noise level.
- Enabled direct observation of correlated spin states by accessing intrinsic spin ensemble fluctuations.
Conclusions:
- Established projection noise-limited readout as a practical method for solid-state quantum sensors.
- Opened new avenues for quantum-enhanced metrology and the detection of many-body correlations.
- Paved the way for implementing spin squeezing in mesoscopic solid-state ensembles.
Related Concept Videos
01:14Atomic Nuclei: Nuclear Spin State Population Distribution
1.7K
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
1.7K
01:03Atomic Nuclei: Nuclear Spin State Overview
1.9K
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
1.9K
01:14NMR Spectrometers: Resolution and Error Correction
994
When magnetic nuclei in a sample achieve resonance and undergo relaxation, the signal detected in NMR is an approximately exponential free induction decay. Fourier transform of an exponential decay yields a Lorentzian peak in the frequency domain. Lorentzian peaks in an NMR spectrum are defined by their amplitude, full width at half maximum, and position, where the peak width is governed by the spin-spin relaxation time alone. In real experiments, however, the applied magnetic field is rendered...
994
01:23Atomic Nuclei: Nuclear Relaxation Processes
1.1K
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.
1.1K
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
1.3K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.3K
01:08Spin–Spin Coupling Constant: Overview
1.2K
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
1.2K