Volume 8 Issue 11, November 2012

Volume 8 Issue 11

Sudden bursts of charged particles emitted from the surface of the Sun can disrupt the satellites orbiting Earth. However, the mechanisms that drive these so-called coronal mass ejections remain unclear. An advanced computer model now establishes a link between the onset of an ejection and the emergence of magnetic flux into the solar atmosphere. Article p845; News & Views p783 COVER IMAGE: COOPER DOWNS AND ILIA IANKOV ROUSSEV COVER DESIGN: ALLEN BEATTIE

Editorials

  • Editorial |

    A unique identifier for every researcher will keep the scientific record in order.

  • Editorial |

    It's been a good month for astronomical discovery and innovation.

Commentary

  • Commentary |

    The Physical Sciences–Oncology Centers in the US bring together scientists from all backgrounds to tackle some of the most important questions in cancer research.

    • David B. Agus
    •  & Franziska Michor

Thesis

Research Highlights

News and Views

  • News & Views |

    A superconducting device that exhibits voltage steps twice as large as expected could harbour Majorana fermions.

    • James R. Williams
    •  & David Goldhaber-Gordon
  • News & Views |

    Topological insulators have an electronic structure that supports topologically protected surface states. Now it seems that crystal symmetry can likewise generate protected states in a new class of materials known as 'topological crystalline insulators'.

    • H. Dennis Drew
  • News & Views |

    A technique for protecting out-of-equilibrium nuclear spin states from thermalization while offering a route to converting them into observable NMR signal is an important contribution to a field that welcomes every bit of extra signal.

    • Andreas Trabesinger
  • News & Views |

    The realization of a Mott insulating state in a system of ultracold fermions comprising far more internal components than the electron, provides an avenue for probing many-body physics that is difficult to access in solids.

    • Congjun Wu
  • News & Views |

    The formation of a macroscopic self-organized electromagnetic-field structure during a collisionless interaction of supersonic plasma streams is challenging existing models of counter-streaming plasmas.

    • Sergey Lebedev

Letters

  • Letter |

    The so-called braking index calculated for the spin-down of rotating neutron stars, or pulsars, doesn’t tally well with observations. But a model accounting for a changing moment of inertia, as an increasing fraction of the stellar core becomes superfluid, can explain the rotational evolution of young pulsars.

    • Wynn C. G. Ho
    •  & Nils Andersson
  • Letter |

    A two-level quantum system driven by an electromagnetic field can oscillate between its two states. The effects of these so-called Rabi oscillations are usually obscured in many-body systems by the variation in properties of the particles involved. Now, however, coherent many-body Rabi oscillations are observed in a vapour made up of several hundred cold rubidium atoms.

    • Y. O. Dudin
    • , L. Li
    • , F. Bariani
    •  & A. Kuzmich
  • Letter |

    The fractional alternating-current Josephson effect produces a series of steps in the current–voltage characteristics of a superconducting junction driven at radiofrequencies. This unusual phenomenon is now observed in a semiconductor–superconductor nanowire. What is more, a doubling in step size when a strong magnetic field is applied could be a possible signature of Majorana fermions, particles that are their own antiparticle.

    • Leonid P. Rokhinson
    • , Xinyu Liu
    •  & Jacek K. Furdyna
  • Letter |

    A topological insulator has surface metallic states that are topologically protected by time-reversal symmetry. Tin telluride is now shown to be a ‘topological crystalline insulator’, in which the surface metallic state is instead protected by the mirror symmetry of the crystal.

    • Y. Tanaka
    • , Zhi Ren
    • , T. Sato
    • , K. Nakayama
    • , S. Souma
    • , T. Takahashi
    • , Kouji Segawa
    •  & Yoichi Ando
  • Letter |

    Extreme ultraviolet and X-ray radiation can be generated when the high harmonics of incident laser light are reflected by a dense plasma, the so-called relativistically oscillating mirror mechanism. Theoretical studies have, however, predicted an alternative regime in which short-wavelength light is generated by dense electron nanobunches that form at the plasma–vacuum boundary. Signatures of this coherent synchrotron emission are now experimentally observed.

    • B. Dromey
    • , S. Rykovanov
    • , M. Yeung
    • , R. Hörlein
    • , D. Jung
    • , D. C. Gautier
    • , T. Dzelzainis
    • , D. Kiefer
    • , S. Palaniyppan
    • , R. Shah
    • , J. Schreiber
    • , H. Ruhl
    • , J. C. Fernandez
    • , C. L. S. Lewis
    • , M. Zepf
    •  & B. M. Hegelich
  • Letter |

    Stable structures can self-assemble in plasmas flowing at supersonic speeds, as evident in many astronomical objects. But now it is also seen in the laboratory using two plasmas travelling in opposite directions, each created by ablating a plastic disc with high-power lasers.

    • N. L. Kugland
    • , D. D. Ryutov
    • , P-Y. Chang
    • , R. P. Drake
    • , G. Fiksel
    • , D. H. Froula
    • , S. H. Glenzer
    • , G. Gregori
    • , M. Grosskopf
    • , M. Koenig
    • , Y. Kuramitsu
    • , C. Kuranz
    • , M. C. Levy
    • , E. Liang
    • , J. Meinecke
    • , F. Miniati
    • , T. Morita
    • , A. Pelka
    • , C. Plechaty
    • , R. Presura
    • , A. Ravasio
    • , B. A. Remington
    • , B. Reville
    • , J. S. Ross
    • , Y. Sakawa
    • , A. Spitkovsky
    • , H. Takabe
    •  & H-S. Park

Articles

  • Article |

    Quantum gases are useful toy models for the study of quantum magnetism. Exquisite control of a spinor gas of fermionic atoms in an optical lattice has now been demonstrated, opening up the exploration of quantum magnetism with high spins.

    • Jasper S. Krauser
    • , Jannes Heinze
    • , Nick Fläschner
    • , Sören Götze
    • , Ole Jürgensen
    • , Dirk-Sören Lühmann
    • , Christoph Becker
    •  & Klaus Sengstock
  • Article |

    Atoms can be used as highly sensitive magnetic-field sensors. By exploiting the effects of electric fields on the optical transitions of excited Rydberg states, it is now demonstrated that it is also possible to probe very weak microwave electric fields with atoms.

    • Jonathon A. Sedlacek
    • , Arne Schwettmann
    • , Harald Kübler
    • , Robert Löw
    • , Tilman Pfau
    •  & James P. Shaffer
  • Article |

    The ability to modify a material’s magnetization with an electric field could enable lower-power electronic devices. Such ‘magnetoelectric’ behaviour is usually only seen at the interface between magnetostrictive and electrostrictive materials, but has now been observed in the bulk of single-component rare-earth ferrites.

    • Yusuke Tokunaga
    • , Yasujiro Taguchi
    • , Taka-hisa Arima
    •  & Yoshinori Tokura
  • Article |

    Sudden bursts of charged particles emitted from the surface of the Sun can disrupt the satellites orbiting Earth. However, the mechanisms that drive these so-called coronal mass ejections remain unclear. An advanced computer model now establishes a link between the onset of an ejection and the emergence of magnetic flux into the solar atmosphere.

    • Ilia I. Roussev
    • , Klaus Galsgaard
    • , Cooper Downs
    • , Noé Lugaz
    • , Igor V. Sokolov
    • , Elena Moise
    •  & Jun Lin