Volume 9 Issue 7, July 2013

Volume 9 Issue 7

An experiment now demonstrates the deterministic continuous variable teleportation between two atomic ensembles at room temperature. This protocol makes it possible to teleport time-evolving quantum states from one ensemble to the other. Letter p400; News & Views p389 IMAGE: HANNA KRAUTER AND DANIEL SALART COVER DESIGN: ALLEN BEATTIE

Editorials

  • Editorial |

    A landmark for the Les Houches series of summer schools underlines the benefit of such activities to researchers of all ages.

  • Editorial |

    A massive electromagnet is making a fantastic voyage from Brookhaven to Fermilab.

Commentary

  • Commentary |

    Any ambitious construction project requires architects and engineers. As research shifts towards large groups that focus on the engineering aspects of linking data to existing models, architectural skills are becoming rare among young theorists.

    • Abraham Loeb

Thesis

Research Highlights

News and Views

  • News & Views |

    Teleportation of simple quantum states of light and matter has already been demonstrated in several experiments. Now the teleportation of continuous-variable states encoded in the collective spin of an atomic ensemble is also possible.

    • Dzmitry Matsukevich
  • News & Views |

    Thermodynamic processes at the microscopic scale can be quite surprising. New limits on the amount of work that can be extracted from a system in an almost deterministic fashion have now been uncovered.

    • Seth Lloyd
  • News & Views |

    Would you ever guess that a microscopic flake of graphite could reverse the diffraction of light? An experiment that demonstrates just such an effect highlights the exciting optical applications of graphene — an atomic layer of carbon with a two-dimensional honeycomb lattice.

    • Yaroslav Urzhumov
    • , Cristian Ciracì
    •  & David R. Smith
  • News & Views |

    Through carefully controlled deposition of graphene on hexagonal boron nitride, an experimental system is created with which to probe the quantum physics of electrons in two dimensions — allowing experimental access to the elusive 'Hofstadter butterfly'.

    • Dieter Weiss
  • News & Views |

    Comparing quantitative calculations of the magnetic field decay of neutron stars and their corresponding spin evolution with observations suggests a high degree of disorder in the inner crust, which might provide evidence for nuclear 'pasta'.

    • William G. Newton
  • News & Views |

    Most multiferroic materials are antiferromagnets, yet ferromagnetism can be induced in bismuth ferrite by substrate-induced strain. Strain is now shown to afford useful control of the orientation of magnetic moments in the multiferroics.

    • Annemieke M. Mulders

Letters

  • Letter |

    An experiment now demonstrates the deterministic continuous-variable teleportation between two atomic ensembles at room temperature. This protocol makes it possible to teleport time-evolving quantum states from one ensemble to the other.

    • H. Krauter
    • , D. Salart
    • , C. A. Muschik
    • , J. M. Petersen
    • , Heng Shen
    • , T. Fernholz
    •  & E. S. Polzik
  • Letter |

    Experiments with ultracold atomic gases can provide insight into more general phenomena, such as spin transport. A study of spin diffusion in a two-dimensional Fermi gas measured the lowest spin diffusion constant so far, approaching its quantum-limited value.

    • Marco Koschorreck
    • , Daniel Pertot
    • , Enrico Vogt
    •  & Michael Köhl
  • Letter |

    The quantum phase transition from a topological to a conventional insulator in In-doped Bi2Se3 occurs when the topological phase is destroyed by the hybridization of states on opposite surfaces. This is characterized by a sudden change in the transport lifetime, measured by means of optical spectroscopy.

    • Liang Wu
    • , M. Brahlek
    • , R. Valdés Aguilar
    • , A. V. Stier
    • , C. M. Morris
    • , Y. Lubashevsky
    • , L. S. Bilbro
    • , N. Bansal
    • , S. Oh
    •  & N. P. Armitage
  • Letter |

    Geometrically frustrated spin-systems do not order magnetically even at absolute zero, forming instead a spin liquid or a glassy state. An organic conductor in which the charges, rather than spins, are frustrated now shows a similar absence of long-range order, resulting in a charge-cluster glass at low temperature.

    • F. Kagawa
    • , T. Sato
    • , K. Miyagawa
    • , K. Kanoda
    • , Y. Tokura
    • , K. Kobayashi
    • , R. Kumai
    •  & Y. Murakami
  • Letter |

    Metamaterials can negatively diffract optical-wavelength light; however, they suffer from high losses and only work over a narrow band of frequencies. Researchers now show how nonlinear optics in thin films of graphite can offer a solution. The negligible thickness of the layers reduces the losses, and the linear band structure of the material ensures broadband operation.

    • Hayk Harutyunyan
    • , Ryan Beams
    •  & Lukas Novotny
  • Letter |

    Magnetic reconnection in the Earth's magnetosphere accelerates electrons. And yet energetic electrons are not created during reconnection in the solar wind. Observations from the Cluster spacecraft now suggest that electron acceleration is caused by repeated bursts of plasma flow, which only occur in situations where the magnetic reconnection is unsteady.

    • H. S. Fu
    • , Yu. V. Khotyaintsev
    • , A. Vaivads
    • , A. Retinò
    •  & M. André

Articles

  • Article |

    A pulsar is a rotating neutron star that beams out electromagnetic waves. The absence of isolated X-ray pulsars with periods longer than 12 s could be a clue to the structural composition of a neutron star’s crust, as simulations show that an amorphous layer would prevent a pulsar from spinning down.

    • José A. Pons
    • , Daniele Viganò
    •  & Nanda Rea
  • Article |

    Magnetic excitations, or spinons, in a quasi-one-dimensional quantum magnet are investigated in an inelastic neutron-scattering experiment. The measurements confirm the existence of theoretically predicted higher-order spinons.

    • Martin Mourigal
    • , Mechthild Enderle
    • , Axel Klöpperpieper
    • , Jean-Sébastien Caux
    • , Anne Stunault
    •  & Henrik M. Rønnow
  • Article |

    Near a quantum critical point there are strong critical fluctuations that destroy standard metallic behaviour. Calculations now show that a pseudogap state can arise in the vicinity of an antiferromagnetic quantum critical point, which might be relevant to the cuprate superconductors.

    • K. B. Efetov
    • , H. Meier
    •  & C. Pépin