Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Free fermion antibunching in a degenerate atomic Fermi gas released from an optical lattice

Nature volume 444, pages 733–736 (2006)Cite this article

Abstract

Noise in a quantum system is fundamentally governed by the statistics and the many-body state of the underlying particles1,2,3,4. The correlated noise5,6,7 observed for bosonic particles (for example, photons8 or bosonic neutral atoms9,10,11,12,13,14) can be explained within a classical field description with fluctuating phases; however, the anticorrelations (‘antibunching’) observed in the detection of fermionic particles have no classical analogue. Observations of such fermionic antibunching are scarce and have been confined to electrons15,16,17 and neutrons18. Here we report the direct observation of antibunching of neutral fermionic atoms. By analysing the atomic shot noise3,10,19 in a set of standard absorption images of a gas of fermionic 40K atoms released from an optical lattice, we find reduced correlations for distances related to the original spacing of the trapped atoms. The detection of such quantum statistical correlations has allowed us to characterize the ordering and temperature of the Fermi gas in the lattice. Moreover, our findings are an important step towards revealing fundamental fermionic many-body quantum phases in periodic potentials, which are at the focus of current research.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Learn more

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Origin of anticorrelations in a Fermi gas released from an optical lattice.
Figure 2: Single shot absorption images and correlation analysis.
Figure 3: Measured correlation amplitude versus temperature of the atomic cloud before loading into the optical lattice.
Figure 4: Calculated noise correlations for 40 K atoms in a one-dimensional lattice.

References

  1. Blanter, Y. M. & Büttiker, M. Shot noise in mesoscopic conductors. Phys. Rep. 336, 1–166 (2000)

    Article  ADS  CAS  Google Scholar 

  2. Beenakker, C. W. J. & Schönenberger, C. Quantum shot noise. Phys. Today 56, 37–42 (2003)

    Article  ADS  Google Scholar 

  3. Altman, E., Demler, E. & Lukin, M. D. Probing many-body states of ultracold atoms via noise correlations. Phys. Rev. A 70, 013603 (2004)

    Article  ADS  Google Scholar 

  4. Polkovnikov, A., Altman, E. & Demler, E. Interference between independent fluctuating condensates. Proc. Natl Acad. Sci. USA 103, 6125–6129 (2006)

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  5. Brown, R. H. & Twiss, R. Q. Correlation between photons in two coherent beams of light. Nature 177, 27–29 (1956)

    Article  ADS  Google Scholar 

  6. Brown, R. H. & Twiss, R. Q. The question of correlation between photons in coherent light rays. Nature 178, 1447–1448 (1956)

    Article  ADS  CAS  Google Scholar 

  7. Baym, G. The physics of Hanbury Brown-Twiss intensity interferometry: From stars to nuclear collisions. Acta Phys. Pol. B 29, 1839–1884 (1998)

    ADS  CAS  Google Scholar 

  8. Mandel, L. & Wolf, E. Optical Coherence and Quantum Optics (Cambridge Univ. Press, Cambridge, New York, 1995)

    Book  Google Scholar 

  9. Yasuda, M. & Shimizu, F. Observation of two-atom correlation of an ultracold neon atomic beam. Phys. Rev. Lett. 77, 3090–3093 (1996)

    Article  ADS  CAS  PubMed  Google Scholar 

  10. Fölling, S. et al. Spatial quantum noise interferometry in expanding ultracold atom clouds. Nature 434, 481–484 (2005)

    Article  ADS  PubMed  Google Scholar 

  11. Schellekens, M. et al. Hanbury Brown Twiss effect for ultracold quantum gases. Science 310, 648–651 (2005)

    Article  ADS  CAS  PubMed  Google Scholar 

  12. Öttl, A., Ritter, S., Köhl, M. & Esslinger, T. Correlations and counting statistics of an atom laser. Phys. Rev. Lett. 95, 090404 (2005)

    Article  ADS  PubMed  Google Scholar 

  13. Esteve, J. et al. Observations of density fluctuations in an elongated Bose gas: Ideal gas and quasicondensate regimes. Phys. Rev. Lett. 96, 130403 (2006)

    Article  ADS  CAS  PubMed  Google Scholar 

  14. Spielman, I. B., Phillips, W. D. & Porto, J. V. The Mott insulator transition in two dimensions. Preprint at 〈http://arxiv.org/cond-mat/0606216〉 (2006)

  15. Oliver, W. D., Kim, J., Liu, R. C. & Yamamoto, Y. Hanbury Brown and Twiss-type experiment with electrons. Science 284, 299–301 (1999)

    Article  ADS  CAS  PubMed  Google Scholar 

  16. Henny, M. et al. The fermionic Hanbury Brown and Twiss experiment. Science 284, 296–298 (1999)

    Article  ADS  CAS  PubMed  Google Scholar 

  17. Kiesel, H., Renz, A. & Hasselbach, F. Observation of Hanbury Brown-Twiss anticorrelations for free electrons. Nature 418, 392–394 (2002)

    Article  ADS  CAS  PubMed  Google Scholar 

  18. Iannuzzi, M., Orecchini, A., Sacchetti, F., Facchi, P. & Pascazio, S. Direct experimental evidence of free-fermion antibunching. Phys. Rev. Lett. 96, 080402 (2006)

    Article  ADS  CAS  PubMed  Google Scholar 

  19. Greiner, M., Regal, C. A., Stewart, J. T. & Jin, D. S. Probing pair-correlated fermionic atoms through correlations in atom shot noise. Phys. Rev. Lett. 94, 110401 (2005)

    Article  ADS  CAS  PubMed  Google Scholar 

  20. Greiner, M., Bloch, I., Mandel, O., Hänsch, T. W. & Esslinger, T. Exploring phase coherence in a 2D lattice of Bose-Einstein condensates. Phys. Rev. Lett. 87, 160405 (2001)

    Article  ADS  CAS  PubMed  Google Scholar 

  21. Köhl, M., Moritz, H., Stöferle, T., Günter, K. & Esslinger, T. Fermionic atoms in a three dimensional optical lattice: Observing Fermi-surfaces, dynamics and interactions. Phys. Rev. Lett. 94, 080403 (2005)

    Article  ADS  PubMed  Google Scholar 

  22. Köhl, M. Thermometry of fermionic atoms in an optical lattice. Phys. Rev. A 73, 031601 (2006)

    Article  ADS  Google Scholar 

  23. Westbrook, C. I. et al. Producing and detecting correlated atoms. Preprint at 〈http://arxiv.org/quant-ph/0609019〉 (2006)

  24. Werner, F., Parcollet, O., Georges, A. & Hassan, S. R. Interaction-induced adiabatic cooling and antiferromagnetism of cold fermions in optical lattices. Phys. Rev. Lett. 95, 056401 (2005)

    Article  ADS  CAS  PubMed  Google Scholar 

  25. Lee, P. A., Nagaosa, N. & Wen, X.-G. Doping a Mott insulator: Physics of high-temperature superconductivity. Rev. Mod. Phys. 78, 17–85 (2006)

    Article  ADS  CAS  Google Scholar 

  26. Hofstetter, W., Cirac, J. I., Zoller, P., Demler, E. & Lukin, M. D. High-temperature superfluidity of fermionic atoms in optical lattices. Phys. Rev. Lett. 89, 220407 (2002)

    Article  ADS  CAS  PubMed  Google Scholar 

  27. Mathey, L., Altman, E. & Vishwanath, A. Noise correlations in one-dimensional systems of ultra-cold fermions. Preprint at 〈http://arxiv.org/cond-mat/0507108〉 (2005)

  28. Wang, D.-W., Lukin, M. D. & Demler, E. Engineering superfluidity in Bose-Fermi mixtures of ultracold atoms. Phys. Rev. A 72, 051604 (2005)

    Article  ADS  Google Scholar 

  29. Ahufinger, V., Sanchez-Palencia, L., Kantian, A., Sanpera, A. & Lewenstein, M. Disordered ultracold atomic gases in optical lattices: A case study of Fermi-Bose mixtures. Phys. Rev. A 72, 063616 (2005)

    Article  ADS  Google Scholar 

  30. Rey, A. M., Indubala, I. S. & Clark, C. W. Quantum coherence of hard-core bosons and fermions: Extended, glassy and Mott phases. Phys. Rev. A 73, 063610 (2006)

    Article  ADS  Google Scholar 

  31. Scarola, V. W., Demler, E. & Sarma, S. D. Searching for a supersolid in cold-atom optical lattices. Phys. Rev. A 73, 051601(R) (2006)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

This work was supported by the DFG, and by the EU under a Marie-Curie excellence grant (QUASICOMBS) and an Integrated Project (SCALA). We acknowledge the technical assistance of T. Berg in the construction of the apparatus.

Author information

Authors and Affiliations

  1. Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, Mainz, 55128, Germany

    T. Rom, Th. Best, D. van Oosten, U. Schneider, S. Fölling, B. Paredes & I. Bloch

Authors
  1. T. Rom
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Th. Best
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. D. van Oosten
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. U. Schneider
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. S. Fölling
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. B. Paredes
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. I. Bloch
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to I. Bloch.

Ethics declarations

Competing interests

Reprints and permissions information is available at www.nature.com/reprints. The authors declare no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Rom, T., Best, T., van Oosten, D. et al. Free fermion antibunching in a degenerate atomic Fermi gas released from an optical lattice. Nature 444, 733–736 (2006). https://doi.org/10.1038/nature05319

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature05319

This article is cited by

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.

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing