Volume 4 Issue 5, May 2008

Volume 4 Issue 5

Spin-polarized neutrons are sensitive to magnetic fields — a property that Nikolay Kardjilov and colleagues use to visualize the three-dimensional distribution of magnetic fields, by analysing the precession of the neutron's magnetic moment. Pictured is the field surrounding a dipole magnet, as detected by the neutrons. But as neutrons can penetrate through matter relatively easily, the approach can also be used to probe magnetic fields inside massive objects. Letter p399

Cover design by David Shand

Editorial

  • Editorial |

    Physics is a hit on the small screen, in US comedy The Big Bang Theory, and takes a leading role in this month's World Science Fair.

Thesis

Books and Arts

Research Highlights

News and Views

  • News & Views |

    Although a driven colloidal suspension is not at equilibrium, a systematic study shows that such a system can still undergo a phase transition — albeit to a randomly organized state.

    • Daan Frenkel
  • News & Views |

    The energy of an atom binding one photon in a cavity can be derived classically. But when two photons are bound to the atom, signatures of light quantization appear in the spectrum. These have now been observed in the optical domain.

    • Howard Carmichael
  • News & Views |

    Experiment has now proved the existence of the predicted three-dimensional 'topological insulator' in the semiconducting alloy Bi1−xSbx.

    • Charles L. Kane
  • News & Views |

    A systematic study of ionization and high harmonic generation in strong laser fields at long wavelengths confirms predictions made 40 years ago, and has important implications for the development of attosecond light sources.

    • John W. G. Tisch
  • News & Views |

    The requirement for an object to be surrounded by empty space when imaged by coherent X-ray diffraction was once thought to be a fundamental limitation. A variant of coherent diffractive imaging proves this not to be the case, and substantially widens its potential use.

    • Janos Hajdu
    •  & Filipe R. N. C. Maia

Review

Letters

  • Letter |

    A magnetic vortex trapped by a notch in a nanowire is no larger than 10 nm, but both the direction and polarity of the vortex can now be measured without applying a magnetic field. In this set-up, the vortex is therefore both stable and switchable for use in possible device applications.

    • Rai Moriya
    • , Luc Thomas
    • , Masamitsu Hayashi
    • , Yaroslaw B. Bazaliy
    • , Charles Rettner
    •  & Stuart S. P. Parkin
  • Letter |

    Valuable insight into the influence of scattering from impurities on the peculiar electronic properties of graphene are gained by a systematic study of how its conductivity changes with increasing concentration of potassium ions deposited on its surface.

    • J.-H. Chen
    • , C. Jang
    • , S. Adam
    • , M. S. Fuhrer
    • , E. D. Williams
    •  & M. Ishigami
  • Letter |

    Nonlinear optics traditionally involves macroscopic atomic ensembles or solid-state crystals. The observation of a nonlinear two-photon resonance in a system consisting of one single atom trapped inside an optical cavity demonstrates nonlinear optics at the level of individual quanta.

    • I. Schuster
    • , A. Kubanek
    • , A. Fuhrmanek
    • , T. Puppe
    • , P. W. H. Pinkse
    • , K. Murr
    •  & G. Rempe
  • Letter |

    A systematic experimental study of the ionization of argon by mid-infrared light confirms half-a-century-old predictions and paves the way to the development of brighter, shorter attosecond pulse sources.

    • P. Colosimo
    • , G. Doumy
    • , C. I. Blaga
    • , J. Wheeler
    • , C. Hauri
    • , F. Catoire
    • , J. Tate
    • , R. Chirla
    • , A. M. March
    • , G. G. Paulus
    • , H. G. Muller
    • , P. Agostini
    •  & L. F. DiMauro
  • Letter |

    A powerful coherent diffractive X-ray imaging technique could enable next generation synchrotrons and free-electron lasers to study much larger samples than previously thought possible.

    • Brian Abbey
    • , Keith A. Nugent
    • , Garth J. Williams
    • , Jesse N. Clark
    • , Andrew G. Peele
    • , Mark A. Pfeifer
    • , Martin de Jonge
    •  & Ian McNulty
  • Letter |

    Spin-polarized neutrons are sensitive to magnetic fields, and they can relatively easily penetrate through matter. A new imaging technique uses these two properties for mapping the three-dimensional distribution of magnetic fields inside massive objects.

    • Nikolay Kardjilov
    • , Ingo Manke
    • , Markus Strobl
    • , André Hilger
    • , Wolfgang Treimer
    • , Michael Meissner
    • , Thomas Krist
    •  & John Banhart
  • Letter |

    Grains, foams and colloids can behave as liquids or solids. Their flow is difficult to predict, often jamming. Such systems are far from equilibrium but there may now be a thermodynamic framework for granular media.

    • Kevin Lu
    • , E. E. Brodsky
    •  & H. P. Kavehpour

Articles

  • Article |

    Laser-driven resolved sideband cooling of the resonant vibrational mode of a toroidal microcavity represents another step towards reaching the quantum ground state.

    • A. Schliesser
    • , R. Rivière
    • , G. Anetsberger
    • , O. Arcizet
    •  & T. J. Kippenberg
  • Article |

    Random collisions between particles usually generate disorder in a system. But under certain conditions, particles in suspended in a liquid subjected to periodic shear forces can collide in a way that leads to fewer subsequent collisions and less disorder.

    • Laurent Corté
    • , P. M. Chaikin
    • , J. P. Gollub
    •  & D. J. Pine

Futures