Volume 7 Issue 5, May 2011

Volume 7 Issue 5

Topological quantum computation schemes — in which quantum information is stored non-locally — provide, in theory, an elegant way of avoiding the deleterious effects of decoherence, but they have proved difficult to realize experimentally. A proposal to engineer topological phases into networks of onedimensional semiconducting wires should bring topological quantum computers a step closer. Article p412 Image courtesy of Erik Lucero, Dario Mariantoni and Matteo Mariantoni.

Editorial

Thesis

Research Highlights

News and Views

  • News & Views |

    An 'attoclock' that measures the relative release time of electrons during double ionization may force us to rethink our use of semi-classical models.

    • Kiyoshi Ueda
    •  & Kenichi L. Ishikawa
  • News & Views |

    Intense femtosecond pulses of infrared light can manipulate molecules. It is now shown that such control even extends to making different molecular eigenstates interfere with each other in a way never considered before — a potential tool for optically engineered chemical reactions and for ultrafast information encoding and manipulation.

    • Thomas Baumert
  • News & Views |

    The observation of quantum phenomena usually requires utmost control and isolation of a quantum system from its noisy environment. A study now shows how even a spontaneously emitted photon may force an atom into a coherent quantum state.

    • Markus Arndt
  • News & Views |

    Elegant but extremely delicate quantum procedures can increase the precision of measurements. Characterizing how they cope with the detrimental effects of noise is essential for deployment to the real world.

    • Lorenzo Maccone
    •  & Vittorio Giovannetti
  • News & Views |

    A century ago, Heike Kamerlingh Onnes discovered superconductivity. And yet, despite the conventional superconductors being understood, the list of unconventional superconductors is growing — for which unconventional theories may be required.

    • Dirk van der Marel
    •  & Mark Golden

Letters

  • Letter |

    An atom recoils as it emits a photon. Researchers now show that the two possible recoil trajectories become coherently superimposed when a mirror is placed near the atom. This is because the mirror prevents the photon from giving away any information about the recoil direction.

    • Jiří Tomkovič
    • , Michael Schreiber
    • , Joachim Welte
    • , Martin Kiffner
    • , Jörg Schmiedmayer
    •  & Markus K. Oberthaler
  • Letter |

    Intense femtosecond pulses of infrared light are frequently used to manipulate molecules. It is now shown that such control even extends to making different molecular eigenstates interfere with each other — an effect that could potentially pave the way to using molecules for quantum information processing.

    • Haruka Goto
    • , Hiroyuki Katsuki
    • , Heide Ibrahim
    • , Hisashi Chiba
    •  & Kenji Ohmori
  • Letter |

    Gate-tunable Andreev bound states that arise within quantum dots formed beneath superconducting contacts deposited on a graphene sheet could be useful in the development of solid-state qubits.

    • Travis Dirks
    • , Taylor L. Hughes
    • , Siddhartha Lal
    • , Bruno Uchoa
    • , Yung-Fu Chen
    • , Cesar Chialvo
    • , Paul M. Goldbart
    •  & Nadya Mason
  • Letter |

    Coating a spherical colloid with a nematic liquid crystal causes frustration-induced defects in the crystal. The thickness of this coating can be used to systematically control the number and orientation of these defects, which could be useful for engineering the microstructure of colloidal materials.

    • T. Lopez-Leon
    • , V. Koning
    • , K. B. S. Devaiah
    • , V. Vitelli
    •  & A. Fernandez-Nieves
  • Letter |

    A liquid droplet placed on a hot surface can levitate, and moreover, self-propel if the surface is textured. Solids can similarly self-propel, which means that the properties of the liquid are irrelevant. Rather, it is the vapour beneath the drop that does the propelling.

    • Guillaume Lagubeau
    • , Marie Le Merrer
    • , Christophe Clanet
    •  & David Quéré

Articles

  • Article |

    Quantum simulations, where one quantum system is used to emulate another, are starting to become experimentally feasible. Here, four-photon states are used to simulate spin tetramers, which are important in the description of certain solid-state systems. Emerging frustration within the tetramer is observed, as well as evolution of the ground state from a localized to a resonating-valence-bond state.

    • Xiao-song Ma
    • , Borivoje Dakic
    • , William Naylor
    • , Anton Zeilinger
    •  & Philip Walther
  • Article |

    Topological quantum computation schemes — where quantum information is stored non-locally — provide, in theory, an elegant way of avoiding the deleterious effects of decoherence, but they have proved difficult to realize experimentally. A proposal to engineer topological phases into networks of one-dimensional semiconducting wires should bring topological quantum computers a step closer.

    • Jason Alicea
    • , Yuval Oreg
    • , Gil Refael
    • , Felix von Oppen
    •  & Matthew P. A. Fisher
  • Article |

    Most of the notable properties of graphene are a result of the cone-like nature of the points in its electronic structure where its conduction and valance bands meet. Similar structures arise in 2D HgTe quantum wells, but without the spin- and valley-degeneracy of graphene; their properties are also likely to be easier to control.

    • B. Büttner
    • , C. X. Liu
    • , G. Tkachov
    • , E. G. Novik
    • , C. Brüne
    • , H. Buhmann
    • , E. M. Hankiewicz
    • , P. Recher
    • , B. Trauzettel
    • , S. C. Zhang
    •  & L. W. Molenkamp
  • Article |

    An ‘attoclock’ that measures the relative release time of electrons during double ionization is now presented. The technique enables investigation of the subtle differences between sequential and non-sequential ionization when elliptically polarized light is used to excite two electrons from argon atoms.

    • Adrian N. Pfeiffer
    • , Claudio Cirelli
    • , Mathias Smolarski
    • , Reinhard Dörner
    •  & Ursula Keller
  • Article |

    Ultracold quantum gases in optical lattices have been used to study a wide range of many-body effects. Nearly all experiments so far, however, have been performed in cubic optical lattice structures. Now a ‘honeycomb’ lattice structure has been realized. The approach promises insight into materials with hexagonal crystal symmetries, such as graphene or carbon nanotubes.

    • P. Soltan-Panahi
    • , J. Struck
    • , P. Hauke
    • , A. Bick
    • , W. Plenkers
    • , G. Meineke
    • , C. Becker
    • , P. Windpassinger
    • , M. Lewenstein
    •  & K. Sengstock