Volume 8 Issue 5, May 2012

Volume 8 Issue 5

A demonstration of the ability to coherently control the collective attosecond dynamics of relativistic electrons driven through a plasma by an intense laser represents an important step in the development of techniques to manipulate and study extreme states of matter. Article p416 IMAGE: ARNAUD MALVACHE AND STÉPHANE HEUET COVER DESIGN: ALLEN BEATTIE

Editorial

  • Editorial |

    Controversial and out-of-line results should not be discarded or hidden — even though revealing them may come at some recriminatory cost, as the OPERA collaboration has discovered.

Correspondence

Thesis

Books and Arts

Research Highlights

News and Views

  • News & Views |

    Two experiments have measured an all-important number in neutrino physics. Going by the innocuous name of 'θ13', this parameter's value has significant implications for our understanding of the Universe.

    • David Wark
  • News & Views |

    Biological systems can adapt to changes in their environment over a wide range of conditions, but responding quickly and accurately is energetically costly. A study pins down the relationship between energy, speed and accuracy.

    • Pieter Rein ten Wolde
  • News & Views |

    An experimental demonstration that the expansion of ultracold atoms in three dimensions can be frozen by disorder provides fertile ground for studies of metal–insulator transitions in disordered systems — including those with interacting particles.

    • Robin Kaiser
  • News & Views |

    The energy gap associated with Cooper pair formation in unconventional superconductors can fall to zero along lines of the Fermi surface. Differences in the shape and location of these lines bear information on the interaction that triggers Cooper pair formation.

    • Dung-Hai Lee

Letters

  • Letter |

    A cross-validation study comparing experimental findings obtained with a system of ultracold fermions with the results of a method based on computing contributions from millions of Feynman diagrams underlines the potential of the so-called bold diagrammatic Monte Carlo technique for solving problems in the area of strongly correlated quantum matter.

    • K. Van Houcke
    • , F. Werner
    • , E. Kozik
    • , N. Prokof’ev
    • , B. Svistunov
    • , M. J. H. Ku
    • , A. T. Sommer
    • , L. W. Cheuk
    • , A. Schirotzek
    •  & M. W. Zwierlein
  • Letter |

    The Cooper pairs of conventional superconductors exhibit a nodeless s-wave symmetry, and most unconventional superconductors, including cuprates and heavy-fermion materials, exhibit nodal d-wave pairing. In contrast to both, angle-resolved photoemission spectroscopy measurements indicate that the iron-based superconductor BaFe2(As0.7P0.3)2 exhibits an unusual nodal s-wave pairing.

    • Y. Zhang
    • , Z. R. Ye
    • , Q. Q. Ge
    • , F. Chen
    • , Juan Jiang
    • , M. Xu
    • , B. P. Xie
    •  & D. L. Feng
  • Letter |

    An outstanding question about the iron-based superconductors has been whether or not their magnetic characteristics are dominated by itinerant or localized magnetic moments. Absolute measurements and calculations of the magnetic response of undoped and Ni-doped BaFe2As2 indicate the latter.

    • Mengshu Liu
    • , Leland W. Harriger
    • , Huiqian Luo
    • , Meng Wang
    • , R. A. Ewings
    • , T. Guidi
    • , Hyowon Park
    • , Kristjan Haule
    • , Gabriel Kotliar
    • , S. M. Hayden
    •  & Pengcheng Dai
  • Letter |

    It is well known that graphene deposited on hexagonal boron nitride produces moiré patterns in scanning tunnelling microscopy images. The interaction that produces this pattern also produces a commensurate periodic potential that generates a set of Dirac points that are different from those of the graphene lattice itself.

    • Matthew Yankowitz
    • , Jiamin Xue
    • , Daniel Cormode
    • , Javier D. Sanchez-Yamagishi
    • , K. Watanabe
    • , T. Taniguchi
    • , Pablo Jarillo-Herrero
    • , Philippe Jacquod
    •  & Brian J. LeRoy
  • Letter |

    Conventional approaches to optomechanics control and monitor the motion of nanoscale mechanical resonators by coupling it to a high-quality photonic cavity. An all-mechanical implementation is now demonstrated by creating a so-called phonon cavity from different oscillating modes of the resonator. This idea opens a route to using solid-state systems to investigate physics not accessible in their analogous, but better developed, quantum-optics counterpart.

    • I. Mahboob
    • , K. Nishiguchi
    • , H. Okamoto
    •  & H. Yamaguchi

Articles

  • Article |

    Commutation relations define the limit to which two complementary properties can be simultaneously known—Heisenberg’s uncertainty principle. Yet it is thought that these canonical relations might be different in the quantum gravity regime. Researchers now show how quantum-optics experiments might provide a direct route for studying these effects.

    • Igor Pikovski
    • , Michael R. Vanner
    • , Markus Aspelmeyer
    • , M. S. Kim
    •  & Časlav Brukner
  • Article |

    An experimental study of three-dimensional localization of ultracold atoms in controlled disorder provides evidence for behaviour that is consistent with Anderson localization, but incompatible with classical trapping.

    • F. Jendrzejewski
    • , A. Bernard
    • , K. Müller
    • , P. Cheinet
    • , V. Josse
    • , M. Piraud
    • , L. Pezzé
    • , L. Sanchez-Palencia
    • , A. Aspect
    •  & P. Bouyer
  • Article |

    The magnetic character of the cuprates is suspected by many to be involved in the emergence of unconventional superconductivity. The discovery of a second distinct magnetic excitation in HgBa2CuO4 supports a multiband picture of the magnetic structure of these materials.

    • Yuan Li
    • , G. Yu
    • , M. K. Chan
    • , V. Balédent
    • , Yangmu Li
    • , N. Barišić
    • , X. Zhao
    • , K. Hradil
    • , R. A. Mole
    • , Y. Sidis
    • , P. Steffens
    • , P. Bourges
    •  & M. Greven
  • Article |

    Spin transfer torque—the transfer of angular momentum from a spin-polarized current to a ferromagnet’s magnetization—has already found commercial application in memory devices, but the underlying physics is still not fully understood. Researchers now demonstrate the crucial role played by the polarization of the laser light that generates the current; a subtle effect only evident when isolated from other influences such as heating.

    • P. Němec
    • , E. Rozkotová
    • , N. Tesařová
    • , F. Trojánek
    • , E. De Ranieri
    • , K. Olejník
    • , J. Zemen
    • , V. Novák
    • , M. Cukr
    • , P. Malý
    •  & T. Jungwirth
  • Article |

    A demonstration of the ability to coherently control the collective attosecond dynamics of relativistic electrons driven through a plasma by an intense laser represents an important step in the development of techniques to manipulate and study extreme states of matter.

    • Antonin Borot
    • , Arnaud Malvache
    • , Xiaowei Chen
    • , Aurélie Jullien
    • , Jean-Paul Geindre
    • , Patrick Audebert
    • , Gérard Mourou
    • , Fabien Quéré
    •  & Rodrigo Lopez-Martens
  • Article |

    It is well known that organisms profit from adapting to their environment. A study of stochastic adaptation dynamics shows that this comes at the expense of adaptive speed and accuracy—providing a framework for understanding adaptation in noisy biological systems.

    • Ganhui Lan
    • , Pablo Sartori
    • , Silke Neumann
    • , Victor Sourjik
    •  & Yuhai Tu
  • Article |

    Small-world topologies characterize many natural and human-built networks. Yet, how such networks organize their link weights is not fully understood. These authors report an organization scheme that captures important features of real-world systems, and identify learning rules that allow evolving networks to obtain such weight organizations based on their history.

    • Sinisa Pajevic
    •  & Dietmar Plenz