Volume 8 Issue 2, February 2012

Volume 8 Issue 2

Chiral superconducting states are expected to support a variety of exotic and potentially useful phenomena. Theoretical analysis suggests that just such a state could emerge in a doped graphene monolayer. Article p158; News & Views p111 COVER IMAGE: ANDREY CHUBUKOV, RAHUL NANDKISHORE AND LEONID LEVITOV COVER DESIGN: ALLEN BEATTIE

Editorials

  • Editorial |

    Nuclear weapons, nuclear power and climate change are driving the march of the Doomsday Clock towards midnight.

  • Editorial |

    The web blackout symbolized concern over potential legislation, which we share.

Thesis

Books and Arts

Research Highlights

News and Views

  • News & Views |

    Two-qubit entanglement can be preserved by partially measuring the qubits to leave them in a 'lethargic' state. The original state is restored using quantum measurement reversal after the qubits have travelled through a decoherence channel.

    • Alexander N. Korotkov
  • News & Views |

    The realization of a single-particle Stirling engine pushes thermodynamics into stochastic territory where fluctuations dominate, and points towards a better understanding of energy transduction at the microscale.

    • Jordan M. Horowitz
    •  & Juan M. R. Parrondo
  • News & Views |

    Graphene exhibits many extraordinary properties, but superconductivity isn't one of them. Two theoretical studies suggest that by decorating the surface of graphene with the right species of dopant atoms, or by using ionic liquid gating, superconductivity could yet be induced.

    • Oskar Vafek
  • News & Views |

    In quantum control there is an inherent tension between high fidelity requirements and the need for speed to avoid decoherence. A direct comparison of quantum control protocols at these two extremes indicates where the sweet spot may lie.

    • Lloyd C. L. Hollenberg
  • News & Views |

    An experimental technique based on Doppler velocimetry provides a detailed picture of electronic spins as they diffuse, drift and turn under the action of an electric field in a two-dimensional electron gas.

    • Giovanni Vignale

Letters

  • Letter |

    Electromagnons are excitations that exhibit both electric and magnetic dipole moments, and are expected to enhance the coupling of magnetization and polarization in multiferroic materials. The identification of electromagnons in a perovskite helimagent may be useful in the development of ways to manipulate light.

    • Youtarou Takahashi
    • , Ryo Shimano
    • , Yoshio Kaneko
    • , Hiroshi Murakawa
    •  & Yoshinori Tokura
  • Letter |

    The discovery that potassium-doped iron selenide undergoes phase separation into a defect-free superconducting phase and an iron-vacancy-ordered insulating phase resolves many questions about the unusual behaviour of this iron-based superconductor.

    • Wei Li
    • , Hao Ding
    • , Peng Deng
    • , Kai Chang
    • , Canli Song
    • , Ke He
    • , Lili Wang
    • , Xucun Ma
    • , Jiang-Ping Hu
    • , Xi Chen
    •  & Qi-Kun Xue
  • Letter |

    Graphene exhibits many extraordinary properties. But, despite many attempts to find ways to induce it, superconductivity is not one of them. First-principles calculations suggest that by decorating the surface of graphene with lithium atoms, it could yet be made to superconduct.

    • Gianni Profeta
    • , Matteo Calandra
    •  & Francesco Mauri
  • Letter |

    Photoelectron spectroscopy is an invaluable tool for better understanding the energy levels of molecules. However, many levels remain hidden because of transition selection rules or a high density of states. Using X-rays to excite core–shell electrons and monitoring their Auger decay enables the extraction of previously hidden molecular-potential curves.

    • Catalin Miron
    • , Christophe Nicolas
    • , Oksana Travnikova
    • , Paul Morin
    • , Yuping Sun
    • , Faris Gel’mukhanov
    • , Nobuhiro Kosugi
    •  & Victor Kimberg
  • Letter |

    When an intense laser pulse hits a flat metal foil, it ejects a spray of high-energy protons. Laser irradiation of a curved foil covering the tip of a hollow cone focuses the protons to intensities that could be useful for generating extreme states of matter.

    • Teresa Bartal
    • , Mark E. Foord
    • , Claudio Bellei
    • , Michael H. Key
    • , Kirk A. Flippo
    • , Sandrine A. Gaillard
    • , Dustin T. Offermann
    • , Pravesh K. Patel
    • , Leonard C. Jarrott
    • , Drew P. Higginson
    • , Markus Roth
    • , Anke Otten
    • , Dominik Kraus
    • , Richard B. Stephens
    • , Harry S. McLean
    • , Emilio M. Giraldez
    • , Mingsheng S. Wei
    • , Donald C. Gautier
    •  & Farhat N. Beg
  • Letter |

    An optically trapped colloidal particle serves as the first realization of a stochastic thermal engine, extending our understanding of the thermodynamics behind the Carnot cycle to microscopic scales where fluctuations dominate.

    • Valentin Blickle
    •  & Clemens Bechinger

Articles

  • Article |

    Transforming a quantum system with high fidelity is usually a trade-off between an increase in speed—thereby minimizing decoherence—and robustness against fluctuating control parameters. Protocols at these two extreme limits are now demonstrated and compared using Bose–Einstein condensates in optical traps.

    • Mark G. Bason
    • , Matthieu Viteau
    • , Nicola Malossi
    • , Paul Huillery
    • , Ennio Arimondo
    • , Donatella Ciampini
    • , Rosario Fazio
    • , Vittorio Giovannetti
    • , Riccardo Mannella
    •  & Oliver Morsch
  • Article |

    An optical technique based on Doppler velocimetry reveals important aspects of the physics underlying the propagation of spin polarization in a two-dimensional electron gas. The spin mobility is shown to track the high electron mobility, but coherent spin precession is lost at temperatures near 150 K, posing a challenge for future spintronics devices.

    • Luyi Yang
    • , J. D. Koralek
    • , J. Orenstein
    • , D. R. Tibbetts
    • , J. L. Reno
    •  & M. P. Lilly
  • Article |

    Chiral superconducting states are expected to support a variety of exotic and potentially useful phenomena. Theoretical analysis suggests that just such a state could emerge in a doped graphene monolayer.

    • Rahul Nandkishore
    • , L. S. Levitov
    •  & A. V. Chubukov
  • Article |

    Glass-forming liquids are generally thought to relax through a collective rearrangement of domains, correlated over a length scale that increases with decreasing temperature. A numerical study now reveals a surprising twist to the story, claiming that relaxation depends non-monotonically on temperature.

    • Walter Kob
    • , Sándalo Roldán-Vargas
    •  & Ludovic Berthier
  • Article |

    A novel mechanism for cooling nanomechanical objects has now been demonstrated. Optically excited electron–hole pairs produce a mechanical stress that damps the motion of a gallium arsenide membrane. In this way, the nanoscale resonator is cooled from room temperature to 4 K.

    • K. Usami
    • , A. Naesby
    • , T. Bagci
    • , B. Melholt Nielsen
    • , J. Liu
    • , S. Stobbe
    • , P. Lodahl
    •  & E. S. Polzik

Corrigenda