Abstract
Not all noise in experimental measurements is unwelcome. Certain fundamental noise sources contain valuable information about the system itself—a notable example being the inherent voltage fluctuations (Johnson noise) that exist across any resistor, which allow the temperature to be determined1,2. In magnetic systems, fundamental noise can exist in the form of random spin fluctuations3,4. For example, statistical fluctuations of N paramagnetic spins should generate measurable noise of order √(N) spins, even in zero magnetic field5,6. Here we exploit this effect to perform perturbation-free magnetic resonance. We use off-resonant Faraday rotation to passively7,8 detect the magnetization noise in an equilibrium ensemble of paramagnetic alkali atoms; the random fluctuations generate spontaneous spin coherences that precess and decay with the same characteristic energy and timescales as the macroscopic magnetization of an intentionally polarized or driven ensemble. Correlation spectra of the measured spin noise reveal g-factors, nuclear spin, isotope abundance ratios, hyperfine splittings, nuclear moments and spin coherence lifetimes—without having to excite, optically pump or otherwise drive the system away from thermal equilibrium. These noise signatures scale inversely with interaction volume, suggesting a possible route towards non-perturbative, sourceless magnetic resonance of small systems.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Johnson, J. B. Thermal agitation of electricity in conductors. Nature 119, 50–51 (1927)
White, D. R. et al. The status of Johnson noise thermometry. Metrologia 33, 325–335 (1996)
Itano, W. M. et al. Quantum projection noise: Population fluctuations in two-level systems. Phys. Rev. A 47, 3554–3570 (1993)
Sorensen, J. L., Hald, J. & Polzik, E. S. Quantum noise of an atomic spin polarization measurement. Phys. Rev. Lett. 80, 3487–3490 (1998)
Bloch, F. Nuclear induction. Phys. Rev. 70, 460–474 (1946)
Sleator, T., Hahn, E. L., Hilbert, C. & Clarke, J. Nuclear-spin noise. Phys. Rev. Lett. 55, 1742–1745 (1985)
Happer, W. & Mathur, B. S. Off-resonant light as a probe of optically-pumped alkali vapors. Phys. Rev. Lett. 18, 577–580 (1967)
Suter, D. & Mlynek, J. Laser excitation and detection of magnetic resonance. Adv. Magn. Opt. Res. 16, 1–83 (1991)
Kubo, R. The fluctuation-dissipation theorem. Rep. Prog. Phys. 29, 255–284 (1966)
Weissman, M. B. What is a spin glass? A glimpse via mesoscopic noise. Rev. Mod. Phys. 65, 829–839 (1993)
Smith, N. & Arnett, P. White-noise magnetization fluctuations in magnetoresistive heads. Appl. Phys. Lett. 78, 1448–1450 (2001)
Awschalom, D. D., DiVincenzo, D. P. & Smyth, J. F. Macroscopic quantum effects in nanometer-scale magnets. Science 258, 414–421 (1992)
Aleksandrov, E. B. & Zapassky, V. S. Magnetic resonance in the Faraday-rotation noise spectrum. Zh. Eksp. Teor. Fiz. 81, 132–138 (1981)
Mitsui, T. Spontaneous noise spectroscopy of an atomic resonance. Phys. Rev. Lett. 84, 5292–5295 (2000)
Kuzmich, A. et al. Quantum nondemolition measurements of collective atomic spin. Phys. Rev. A 60, 2346–2350 (1999)
Kuzmich, A., Mandel, L. & Bigelow, N. P. Generation of spin squeezing via continuous quantum nondemolition measurement. Phys. Rev. Lett. 85, 1594–1597 (2000)
Mamin, H. J., Budakian, R., Chui, B. W. & Rugar, D. Detection and manipulation of statistical polarization in small spin ensembles. Phys. Rev. Lett. 91, 207604 (2003)
Manassen, Y., Hamers, R. J., Demuth, J. E. & Castellano, A. J. Direct observation of the precession of individual paramagnetic spins on oxidized silicon surfaces. Phys. Rev. Lett. 62, 2531–2534 (1989)
Nussinov, Z., Crommie, M. F. & Balatsky, A. V. Noise spectroscopy of a single spin with spin-polarized STM. Phys. Rev. B 68, 085402 (2003)
Cleland, A. N. & Roukes, M. L. Noise processes in nanomechanical resonators. J. Appl. Phys. 92, 2758–2769 (2002)
Weaver, R. L. & Lobkis, O. I. Ultrasonics without a source: Thermal fluctuation correlations at MHz frequencies. Phys. Rev. Lett. 87, 134301 (2001)
Kastler, A. Optical methods for studying Hertzian resonances. Science 158, 214–221 (1967)
Happer, W. Optical pumping. Rev. Mod. Phys. 44, 169–249 (1972)
Corney, A. Atomic and Laser Spectroscopy (Clarendon, Oxford, 1977)
Yabuzaki, T., Mitsui, T. & Tanaka, U. New type of high-resolution spectroscopy with a diode laser. Phys. Rev. Lett. 67, 2453–2456 (1991)
Ito, T., Shimomura, N. & Yabuzaki, T. Noise spectroscopy of K atoms with a diode laser. J. Phys. Soc. Jpn 72, 962–963 (2003)
Jury, J. C., Klaassen, K. B., van Peppen, J. & Wang, S. X. Measurement and analysis of noise sources in magnetoresistive sensors up to 6 GHz. IEEE Trans. Magn. 38, 3545–3555 (2002)
Wolf, S. A. et al. Spintronics: A spin-based electronics vision for the future. Science 294, 1488–1495 (2001)
Imamoglu, A. et al. Quantum information processing using quantum dot spins and cavity QED. Phys. Rev. Lett. 83, 4204–4207 (1999)
Joglekar, Y. N., Balatsky, A. V. & MacDonald, A. H. Noise spectroscopy and interlayer phase coherence in bilayer quantum Hall systems. Phys. Rev. Lett. 92, 086803 (2004)
Acknowledgements
We thank P. Littlewood, S. Gider, P. Crowell and P. Crooker for discussions. This work was supported by the Los Alamos LDRD programme.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Competing interests
The authors declare that they have no competing financial interests.
Supplementary information
Supplementary Figure
An additional figure of spin noise data, this time from atoms having nuclear spin 5/2. (PDF 169 kb)
Rights and permissions
About this article
Cite this article
Crooker, S., Rickel, D., Balatsky, A. et al. Spectroscopy of spontaneous spin noise as a probe of spin dynamics and magnetic resonance. Nature 431, 49–52 (2004). https://doi.org/10.1038/nature02804
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/nature02804
This article is cited by
-
Discovery of ultrafast spontaneous spin switching in an antiferromagnet by femtosecond noise correlation spectroscopy
Nature Communications (2023)
-
Quantum nonlinear spectroscopy of single nuclear spins
Nature Communications (2022)
-
Optical detection of electron spin dynamics driven by fast variations of a magnetic field: a simple method to measure \(T_1\), \(T_2\), and \(T_2^*\) in semiconductors
Scientific Reports (2020)
-
Optical spin noise spectra of Rb atomic gas with homogeneous and inhomogeneous broadening
Scientific Reports (2017)
-
Spin noise explores local magnetic fields in a semiconductor
Scientific Reports (2016)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.