Volume 9 Issue 5, May 2013

Volume 9 Issue 5

Editorial

  • Editorial |

    Creating a sustainable future based on clean energy from renewable sources is the challenge facing incoming US energy secretary Ernest Moniz. Elsewhere in the world, progress is already being made.

Thesis

Books and Arts

Research Highlights

News and Views

  • News & Views |

    Granular materials, ranging from fruit to rocks to powders, can change rapidly from a static jammed state to a free-flowing state. Insight from dynamical systems theory reveals that this tendency is governed by the growth of instabilities, rather than stress on individual particles.

    • Troy Shinbrot
  • News & Views |

    The ability to manipulate the spin orientation of the highly spin-polarized photoelectrons ejected from topologically protected surface electrons by light polarization may pave the way for opto-spintronics applications using topological insulators.

    • Qi-Kun Xue
  • News & Views |

    Engineering the interactions between atoms allows a fragile system in its quantum degenerate state to persist for much longer than equilibrium statistical physics would otherwise allow.

    • Jörg Schmiedmayer
  • News & Views |

    In the light of more data, the particle discovered at CERN last year is now confirmed to be a Higgs boson — but what kind of Higgs boson? And what might the discovery mean for theories that reach beyond the standard model?

    • Herbi Dreiner
  • News & Views |

    In electron spin resonance techniques, spins are usually manipulated by applying external magnetic fields, but the same effect can be obtained by guiding electrons along a meandering path using surface acoustic waves.

    • Masaya Kataoka

Letters

  • Letter |

    A Bose–Einstein condensate can exist in a superheated state well above the critical temperature if the interaction strength is tuned low. When the interactions are switched back on, the condensate boils away.

    • Alexander L. Gaunt
    • , Richard J. Fletcher
    • , Robert P. Smith
    •  & Zoran Hadzibabic
  • Letter |

    The Josephson effects that arise when two quantum states are coupled through a barrier are difficult to observe in optical systems because photon–photon interactions are so weak. Researchers have now demonstrated an optical realization of two such phenomena—macroscopic self-trapping and Josephson oscillations—using polariton condensates in overlapping microcavities.

    • M. Abbarchi
    • , A. Amo
    • , V. G. Sala
    • , D. D. Solnyshkov
    • , H. Flayac
    • , L. Ferrier
    • , I. Sagnes
    • , E. Galopin
    • , A. Lemaître
    • , G. Malpuech
    •  & J. Bloch
  • Letter |

    In traditional electron spin resonance techniques external magnetic fields are required. Now the electron spin can be manipulated in the absence of an applied magnetic field, by a technique that exploits the spin–orbit coupling of electrons travelling on surface acoustic waves.

    • H. Sanada
    • , Y. Kunihashi
    • , H. Gotoh
    • , K. Onomitsu
    • , M. Kohda
    • , J. Nitta
    • , P. V. Santos
    •  & T. Sogawa
  • Letter |

    Graphene may be set to revolutionize electronics, but its small spin–orbit coupling limits its potential in spintronics. It is now shown, however, that adding hydrogen atoms can greatly enhance the magnetic properties of graphene. This then enabled the observation of the spin Hall effect, essential for controlling spin currents.

    • Jayakumar Balakrishnan
    • , Gavin Kok Wai Koon
    • , Manu Jaiswal
    • , A. H. Castro Neto
    •  & Barbaros Özyilmaz
  • Letter |

    Free-flowing granular media can quickly become jammed above a critical density. Nonlinear dynamical systems analysis now suggests that jamming arises from the interaction between the density of instabilities and the propagation of disturbances throughout the material.

    • Edward J. Banigan
    • , Matthew K. Illich
    • , Derick J. Stace-Naughton
    •  & David A. Egolf
  • Letter |

    In a topological insulator, the surface-state electron spins are ‘locked’ to their direction of travel. But when an electron is kicked out by a photon through the photoelectric effect, the spin polarization is not necessarily conserved. In fact, the ejected spins can be completely manipulated in three dimensions by the incident photons.

    • Chris Jozwiak
    • , Cheol-Hwan Park
    • , Kenneth Gotlieb
    • , Choongyu Hwang
    • , Dung-Hai Lee
    • , Steven G. Louie
    • , Jonathan D. Denlinger
    • , Costel R. Rotundu
    • , Robert J. Birgeneau
    • , Zahid Hussain
    •  & Alessandra Lanzara

Articles

  • Article |

    A crystal is a band insulator if the energy bands are filled with electrons. Partially filled bands result in a metal, or sometimes a Mott insulator when interactions are strong. A study now shows that for many crystalline structures, the Mott insulator is the only possible insulating state, even for filled bands.

    • Siddharth A. Parameswaran
    • , Ari M. Turner
    • , Daniel P. Arovas
    •  & Ashvin Vishwanath
  • Article |

    It has been suggested that plasmonic nanostructures could boost nonlinear optical processes in atoms. However, an incomplete understanding of the complex physics in such systems has hampered attempts to harness this idea in applications. An in-depth study now shows that phenomena such as high-harmonic generation might in fact be limited by the tiny volumes involved at the nanoscale.

    • M. Sivis
    • , M. Duwe
    • , B. Abel
    •  & C. Ropers
  • Article |

    Active materials, such as motile cells and self-propelled colloids, exhibit glassy effects, but little is known about the glass transition far from equilibrium. A study of model glasses subject to non-thermal driving and dissipation reveals signatures of dynamic arrest that can be understood in terms of an effective equilibrium description.

    • Ludovic Berthier
    •  & Jorge Kurchan