Volume 4 Issue 12, December 2008

Volume 4 Issue 12

Live neuronal cultures patterned into quasi-one-dimensional arrays can function, depending on the configuration, as diodes (shown on the cover) or as logic gates. The work also illustrates the role of redundancy in such complex networks; the devices work with lower error rates than the constituent neurons, suggesting that redundancy-based error correction is at work. Article p967; News & Views p905

Cover design by David Shand

Editorial

  • Editorial |

    As we research the workings of the human brain, attempting to understand and even mimic its function, do we risk passing a point of no return?

Commentary

  • Commentary |

    The discovery of a new class of high-temperature superconductors based on iron tests the limits of current theoretical and computational tools for the understanding of strongly correlated systems.

    • Cenke Xu
    •  & Subir Sachdev

Thesis

Research Highlights

News and Views

  • News & Views |

    Nerve cells have the ability to self-organize into strongly interacting networks, even when grown in a Petri dish. Controlling the geometry of such cell cultures might be all that is needed to set up neuronal computing devices.

    • Fred Wolf
    •  & Theo Geisel
  • News & Views |

    An adapted scanning electron microscope allows the non-destructive measurement and manipulation of Bose–Einstein condensates. The single-atom sensitivity that this technique promises could soon become indispensable in the study of quantum degenerate atomic gases.

    • Dieter Jaksch
  • News & Views |

    Entanglement is precious, allowing us to perform all kinds of quantum tricks. But it is easily buried under technical noise. Two experiments show how to distil the 'good parts' from a data stream and recover high-quality entanglement.

    • Hans-Albert Bachor
  • News & Views |

    The demonstration of an optical clock in which individual atoms are confined in a three-dimensional optical lattice moves us closer to the atomic clockmaker's dream: tens of thousands of isolated atoms that work in parallel.

    • Chris Oates
  • News & Views |

    Polar diatomic molecules, consisting of potassium and rubidium, have been created with density and temperature close to the regime of quantum degeneracy.

    • David DeMille
    •  & Eric R. Hudson

Letters

  • Letter |

    Two independent experiments demonstrate that quantum entanglement that has been lost in decoherence processes can be recovered. For the first time such ’entanglement distillation’ has been achieved for states of light that are entangled in continuous variables, which should help to increase the distance over which quantum information can be distributed.

    • Boris Hage
    • , Aiko Samblowski
    • , James DiGuglielmo
    • , Alexander Franzen
    • , Jaromír Fiurášek
    •  & Roman Schnabel
  • Letter |

    Two independent experiments demonstrate that quantum entanglement that has been lost in decoherence processes can be recovered. For the first time such ‘entanglement distillation’ has been achieved for states of light that are entangled in continuous variables, which should help to increase the distance over which quantum information can be distributed.

    • Ruifang Dong
    • , Mikael Lassen
    • , Joel Heersink
    • , Christoph Marquardt
    • , Radim Filip
    • , Gerd Leuchs
    •  & Ulrik L. Andersen
  • Letter |

    An experiment that demonstrates efficient absorption of light by a single atom residing in free space should be helpful for designing interfaces for the transfer of quantum information from ‘flying’ qubits to stationary quantum systems, without the need for optical cavities.

    • Meng Khoon Tey
    • , Zilong Chen
    • , Syed Abdullah Aljunid
    • , Brenda Chng
    • , Florian Huber
    • , Gleb Maslennikov
    •  & Christian Kurtsiefer
  • Letter |

    Evidence for metal–insulator transitions in dilute 2D electron gases has sparked controversy and debate. A new model suggests such behaviour could arise from strong correlations driven by non-local Coulomb interactions, providing an alternative view to that which considers disorder to be the over-riding influence.

    • A. Camjayi
    • , K. Haule
    • , V. Dobrosavljević
    •  & G. Kotliar
  • Letter |

    Application of extreme magnetic fields to a low-disorder 2D electron gas causes its electrons to reorder through an unexpected transition from a 2D to quasi-3D Wigner crystal state.

    • B. A. Piot
    • , Z. Jiang
    • , C. R. Dean
    • , L. W. Engel
    • , G. Gervais
    • , L. N. Pfeiffer
    •  & K. W. West
  • Letter |

    Warm dense matter is a complex and little-explored state that is characterized by temperatures usually associated with plasmas but at densities similar to solids. A combination of inelastic X-ray scattering and ab initio simulations enables insight into its structure and behaviour.

    • E. García Saiz
    • , G. Gregori
    • , D. O. Gericke
    • , J. Vorberger
    • , B. Barbrel
    • , R. J. Clarke
    • , R. R. Freeman
    • , S. H. Glenzer
    • , F. Y. Khattak
    • , M. Koenig
    • , O. L. Landen
    • , D. Neely
    • , P. Neumayer
    • , M. M. Notley
    • , A. Pelka
    • , D. Price
    • , M. Roth
    • , M. Schollmeier
    • , C. Spindloe
    • , R. L. Weber
    • , L.  van Woerkom
    • , K. Wünsch
    •  & D. Riley
  • Letter |

    A systematic study of the propagation of ultrasound through a random network of aluminium beads provides the first demonstration of the Anderson localization of classical waves in a 3D system.

    • Hefei Hu
    • , A. Strybulevych
    • , J. H. Page
    • , S. E. Skipetrov
    •  & B. A. van Tiggelen

Articles

  • Article |

    Electron microscopes are regularly used to resolve atoms in solid samples. It turns out that they can also be used to image atoms in a Bose–Einstein condensate—remarkably, without destroying the coherent properties of the condensate.

    • Tatjana Gericke
    • , Peter Würtz
    • , Daniel Reitz
    • , Tim Langen
    •  & Herwig Ott
  • Article |

    Optical lattice clocks, in which trapped atoms serve as a frequency reference, are promising candidates for next-generation atomic clocks. Depending on whether bosons or fermions are loaded into the lattice, fundamentally different design principles apply, as has now been shown.

    • Tomoya Akatsuka
    • , Masao Takamoto
    •  & Hidetoshi Katori
  • Article |

    The tendency of small objects to stick together as they come into contact is a commonly observed phenomenon. Yet the interactions that govern this behaviour can be complex. A systematic study of the variation in the force between a particle and a solid surface as they are brought together finds many parallels with the characteristics of glassy and granular systems.

    • Prerna Sharma
    • , Shankar Ghosh
    •  & S. Bhattacharya
  • Article |

    The computational capability of the brain remains a mystery. Some insight might come from a series of experiments in which cultures of living neurons are patterned in a way to form functional logic devices.

    • Ofer Feinerman
    • , Assaf Rotem
    •  & Elisha Moses

Futures