Volume 5 Issue 9, September 2009

Volume 5 Issue 9

The dynamics at a black-hole event horizon are tricky to study experimentally. But by exploiting the strong nonlinear optical response of metamaterials it could be possible to engineer optical singularites that mimic the behaviour of black holes and other massive celestial objects – and bring experimental astrophysics into the lab. Article p687 Cover design by David Shand

Editorials

  • Editorial |

    Public trust in science is vital. But how do we ensure trust without imposing authority?

  • Editorial |

    'Fun' science may grab summer headlines, but only the real thing has a lasting effect.

Perspective

  • Perspective |

    In his short career, Ettore Majorana made several profound contributions. One of them, his concept of 'Majorana fermions' — particles that are their own antiparticle — is finding ever wider relevance in modern physics.

    • Frank Wilczek

Thesis

Books and Arts

Research Highlights

News and Views

  • News & Views |

    Whether the magnetic response of the copper oxide high-temperature superconductors is governed by itinerant quasiparticles or localized electrons is a hotly debated question. Evidence for the latter suggests an intricate connection to the parent Mott insulator.

    • Matthias Vojta
  • News & Views |

    Rain hits the ground in drops of different sizes, but the mechanism that produces this distribution is unclear. Could it be that all we need to know is contained in the death of a single drop?

    • Alexander B. Kostinski
    •  & Raymond A. Shaw
  • News & Views |

    The nature of the 'hidden order' in URu2Si2 has resisted characterization for the past twenty-five years. Recent photoemission results report the observation of a narrow heavy-fermion band that sharpens below the mysterious transition and provides new clues about its origins.

    • P. Chandra
    •  & P. Coleman
  • News & Views |

    Incorporating structural features into random-graph calculations should bring theoretical models describing the properties and behaviour of complex networks closer to real-world systems.

    • Raissa M. D'Souza
  • News & Views |

    An optical analysis reveals that the electronic correlations in the 'parent' compounds of the iron pnictide superconductors are sufficiently strong to significantly impede the mobility of the electrons.

    • Qimiao Si
  • News & Views |

    The conventional photovoltaic effect has now been given a spin twist, enabling spin control in a non-magnetic structure. This concept could yield new methods of detecting and tailoring spin-dependent phenomena in semiconductors.

    • Igor Žutić

Letters

  • Letter |

    In quantum information science, dissipation is commonly viewed as an adverse effect that destroys information through decoherence. But theoretical work shows that dissipation can be used to drive quantum systems to a desired state, and therefore might serve as a resource in quantum computations.

    • Frank Verstraete
    • , Michael M. Wolf
    •  & J. Ignacio Cirac
  • Letter |

    URu2Si2 is full of mystery. Despite having f-electrons, it is unclear whether heavy electrons are present in the ‘hidden order’ phase. Thanks to photoemission studies, itinerant heavy electrons have been observed just above the hidden-order phase transition, below which the electronic energy spectrum develops a gap.

    • Andrés F. Santander-Syro
    • , Markus Klein
    • , Florin L. Boariu
    • , Andreas Nuber
    • , Pascal Lejay
    •  & Friedrich Reinert
  • Letter |

    A systematic neutron-scattering study of large near-optimally doped single crystals of the cuprate superconductor, Bi2Sr2CaCu2O8+δ, indicates that its magnetic properties are governed by localized magnetic moments, and not by itinerant quasiparticles, as widely expected.

    • Guangyong Xu
    • , G. D. Gu
    • , M. Hücker
    • , B. Fauqué
    • , T. G. Perring
    • , L. P. Regnault
    •  & J. M. Tranquada
  • Letter |

    When electrons experience Coulomb repulsion, their kinetic energy becomes significantly reduced. This effect has now been measured in the pnictide superconductor LaFePO, and shows that correlations between electrons in these materials are just as strong as in some copper oxide and ruthenate superconductors.

    • M. M. Qazilbash
    • , J. J. Hamlin
    • , R. E. Baumbach
    • , Lijun Zhang
    • , D. J. Singh
    • , M. B. Maple
    •  & D. N. Basov
  • Letter |

    A two-dimensional lattice of vortices melts into an isotropic liquid with increasing temperature. A microscopic view of the melting transition reveals that this actually occurs in three steps, one of which is an unusual liquid-crystal-like vortex phase.

    • I. Guillamón
    • , H. Suderow
    • , A. Fernández-Pacheco
    • , J. Sesé
    • , R. Córdoba
    • , J. M. De Teresa
    • , M. R. Ibarra
    •  & S. Vieira
  • Letter |

    The magnetization of a magnetic random-access memory is usually controlled by the injection of an externally polarized spin-current. A proof-of-principle demonstration shows that this could instead be manipulated with local fields generated by spin–orbit interactions of an unpolarized current.

    • Alexandr Chernyshov
    • , Mason Overby
    • , Xinyu Liu
    • , Jacek K. Furdyna
    • , Yuli Lyanda-Geller
    •  & Leonid P. Rokhinson
  • Letter |

    Electromagnetically induced transparency in an atomic gas can slow the propagation of images. It is now shown that the diffraction of such images as they propagate can be controlled and even eliminated. This is achieved by using atomic diffusion to influence the spreading of the image.

    • Ofer Firstenberg
    • , Paz London
    • , Moshe Shuker
    • , Amiram Ron
    •  & Nir Davidson

Articles

  • Article |

    The effect of disorder in conventional two-dimensional electron systems is usually described in terms of individual electrons interacting with an underlying disorder potential. Scanning single-electron transistor measurements of graphene in a strong magnetic field indicate that in this system, coulombic interactions between electrons must also be taken into account.

    • J. Martin
    • , N. Akerman
    • , G. Ulbricht
    • , T. Lohmann
    • , K. von Klitzing
    • , J. H. Smet
    •  & A. Yacoby
  • Article |

    A technique that allows the electrical detection of spin-polarized transport in semiconductors without disturbing the spin-polarized current or using magnetic elements has now been demonstrated. The approach could lead to the integration of spintronics elements into semiconductor microelectronic circuits.

    • J. Wunderlich
    • , A. C. Irvine
    • , Jairo Sinova
    • , B. G. Park
    • , L. P. Zârbo
    • , X. L. Xu
    • , B. Kaestner
    • , V. Novák
    •  & T. Jungwirth
  • Article |

    Pumping an atomic system with light at a wavelength that is longer than its resonance can lead to cooling. Conversely, it is now shown that pumping with shorter-wavelength light can lead to the stimulated emission of phonons—in analogy to the amplification of photons in lasers.

    • K. Vahala
    • , M. Herrmann
    • , S. Knünz
    • , V. Batteiger
    • , G. Saathoff
    • , T. W. Hänsch
    •  & Th. Udem
  • Article |

    Black holes are difficult to study experimentally, owing to their distance from us and indeed their very nature. A theoretical study suggests that optical metamaterials that exhibit behaviour that is reminiscent of that of black holes, could enable us to learn more about these and other astrophysical objects.

    • Dentcho A. Genov
    • , Shuang Zhang
    •  & Xiang Zhang
  • Article |

    The first experimental demonstration of saturable absorption in core-electron transitions in aluminium paves the way for investigating warm dense matter, which potentially has an important role in planetary science and the realization of inertial confinement fusion.

    • Bob Nagler et al.
    • , Bob Nagler
    • , Ulf Zastrau
    • , Roland R. Fäustlin
    • , Sam M. Vinko
    • , Thomas Whitcher
    • , A. J. Nelson
    • , Ryszard Sobierajski
    • , Jacek Krzywinski
    • , Jaromir Chalupsky
    • , Elsa Abreu
    • , Saša Bajt
    • , Thomas Bornath
    • , Tomas Burian
    • , Henry Chapman
    • , Jaroslav Cihelka
    • , Tilo Döppner
    • , Stefan Düsterer
    • , Thomas Dzelzainis
    • , Marta Fajardo
    • , Eckhart Förster
    • , Carsten Fortmann
    • , Eric Galtier
    • , Siegfried H. Glenzer
    • , Sebastian Göde
    • , Gianluca Gregori
    • , Vera Hajkova
    • , Phil Heimann
    • , Libor Juha
    • , Marek Jurek
    • , Fida Y. Khattak
    • , Ali Reza Khorsand
    • , Dorota Klinger
    • , Michaela Kozlova
    • , Tim Laarmann
    • , Hae Ja Lee
    • , Richard W. Lee
    • , Karl-Heinz Meiwes-Broer
    • , Pascal Mercere
    • , William J. Murphy
    • , Andreas Przystawik
    • , Ronald Redmer
    • , Heidi Reinholz
    • , David Riley
    • , Gerd Röpke
    • , Frank Rosmej
    • , Karel Saksl
    • , Romain Schott
    • , Robert Thiele
    • , Josef Tiggesbäumker
    • , Sven Toleikis
    • , Thomas Tschentscher
    • , Ingo Uschmann
    • , Hubert J. Vollmer
    •  & Justin S. Wark
  • Article |

    The size-distribution profile of raindrops when they reach the ground was previously thought to be governed by complex interactions between neighbouring droplets as they fall. High-speed videos of falling water droplets suggest this is not the case, and that their size distribution can be explained by the fragmentation of individual droplets alone.

    • Emmanuel Villermaux
    •  & Benjamin Bossa