Volume 11 Issue 2, February 2015

Volume 11 Issue 2

Mechanical metamaterials are artificial structures whose properties originate from their geometry. In such structures, it is now shown that topological modes can exist that are robust against a range of structural deformations.Letter p153; News & Views p95 IMAGE: JAYSON PAULOSE COVER DESIGN: ALLEN BEATTIE

Editorials

Commentaries

  • Commentary |

    Our framework for understanding non-equilibrium behaviour is yet to match the simplicity and power of equilibrium statistical physics. But recent theoretical and experimental advances reveal key principles that unify seemingly unrelated topics.

    • Christopher Jarzynski

Research Highlights

News and Views

  • News & Views |

    The Higgs mechanism is normally associated with high energy physics, but its roots lie in superconductivity. And now there is evidence for a Higgs mode in disordered superconductors near the superconductor–insulator transition.

    • Philip W. Anderson
  • News & Views |

    The valley index of an electron is a magnetic moment that can be initialized optically and probed electrically. Now, experiments reveal how magnetic fields can break the degeneracy for states with different valley indices.

    • Bernhard Urbaszek
    •  & Xavier Marie
  • News & Views |

    Even simple periodic mechanical lattices can exhibit exotic topologically protected modes. Incorporating defects into the mix makes things more interesting — revealing modes whose characteristics depend on properties of both the lattice and the defect.

    • Thomas Witten
  • News & Views |

    The Rosetta orbiter following Comet 67P has captured not only the public imagination but also actual dust grains from the comet's nucleus, revealing their composition, morphology and strength.

    • David Jewitt
  • News & Views |

    The successful formation of self-generated magnetic fields in the lab using large-scale, high-power lasers opens the door to a better understanding of some of the most extreme astrophysical processes taking place in the Universe.

    • Francisco Suzuki-Vidal
  • News & Views |

    The monopole picture for spin ice offers a natural description of a confounding class of materials. A 2009 paper in Nature Physics applied it to study the dynamical properties of these systems — sparking intense experimental and theoretical efforts in the years that followed.

    • Claudio Castelnovo

Thesis

Perspective

  • Perspective |

    Fluctuation theorems go beyond the linear response regime to describe systems far from equilibrium. But what happens to these theorems when we enter the quantum realm? The answers, it seems, are now coming thick and fast.

    • Peter Hänggi
    •  & Peter Talkner

Progress Articles

  • Progress Article |

    Equilibrium physics is ill-equipped to explain all of life’s subtleties, largely because living systems are out of equilibrium. Attempts to overcome this problem have given rise to a lively field of research—and some surprising biological findings.

    • J. Prost
    • , F. Jülicher
    •  & J-F. Joanny
  • Progress Article |

    Experiments probing non-equilibrium processes have so far been tailored largely to classical systems. The endeavour to extend our understanding into the quantum realm is finding traction in studies of electronic circuits at sub-kelvin temperatures.

    • Jukka P. Pekola

Reviews

  • Review Article |

    Statistical mechanics is adept at describing the equilibria of quantum many-body systems. But drive these systems out of equilibrium, and the physics is far from clear. Recent advances have broken new ground in probing these equilibration processes.

    • J. Eisert
    • , M. Friesdorf
    •  & C. Gogolin
  • Review Article |

    The task of integrating information into the framework of thermodynamics dates back to Maxwell and his infamous demon. Recent advances have made these ideas rigorous—and brought them into the laboratory.

    • Juan M. R. Parrondo
    • , Jordan M. Horowitz
    •  & Takahiro Sagawa

Letters

  • Letter |

    Charge carriers in transition metal dichalcogenides have an extra degree of freedom known as valley pseudospin, which is associated with the shape of the energy bands. Experiments show that this pseudospin can be manipulated using magnetic fields.

    • Ajit Srivastava
    • , Meinrad Sidler
    • , Adrien V. Allain
    • , Dominik S. Lembke
    • , Andras Kis
    •  & A. Imamoğlu
  • Letter |

    Charge carriers in transition metal dichalcogenides have an extra degree of freedom known as valley pseudospin, which is associated with the shape of the energy bands. Experiments show that this pseudospin can be manipulated using magnetic fields.

    • G. Aivazian
    • , Zhirui Gong
    • , Aaron M. Jones
    • , Rui-Lin Chu
    • , J. Yan
    • , D. G. Mandrus
    • , Chuanwei Zhang
    • , David Cobden
    • , Wang Yao
    •  & X. Xu
  • Letter |

    Mechanical metamaterials are artificial structures whose properties originate from their geometry. In such structures, it is now shown that topological modes can exist that are robust against a range of structural deformations.

    • Jayson Paulose
    • , Bryan Gin-ge Chen
    •  & Vincenzo Vitelli
  • Letter |

    To gain insight into the properties of quantum matter, a superatom—an ensemble of strongly interacting atoms in the Rydberg blockade regime—is created and characterized by precisely controlling the density and Rydberg excitations.

    • T. M. Weber
    • , M. Höning
    • , T. Niederprüm
    • , T. Manthey
    • , O. Thomas
    • , V. Guarrera
    • , M. Fleischhauer
    • , G. Barontini
    •  & H. Ott
  • Letter |

    Chern numbers characterize the quantum Hall effect conductance—non-zero values are associated with topological phases. Previously only spotted in electronic systems, they have now been measured in ultracold atoms subject to artificial gauge fields.

    • M. Aidelsburger
    • , M. Lohse
    • , C. Schweizer
    • , M. Atala
    • , J. T. Barreiro
    • , S. Nascimbène
    • , N. R. Cooper
    • , I. Bloch
    •  & N. Goldman
  • Letter |

    The quantum mechanical concept of ‘steering’ refers to the feasibility of one system to nonlocally affect, or steer, another system’s states through local measurements. Multipartite steering is now demonstrated in a programmable optical network.

    • Seiji Armstrong
    • , Meng Wang
    • , Run Yan Teh
    • , Qihuang Gong
    • , Qiongyi He
    • , Jiri Janousek
    • , Hans-Albert Bachor
    • , Margaret D. Reid
    •  & Ping Koy Lam
  • Letter |

    Astrophysical processes are often driven by collisionless plasma shock waves. The Weibel instability, a possible mechanism for developing such shocks, has now been generated in a laboratory set-up with laser-generated plasmas.

    • C. M. Huntington
    • , F. Fiuza
    • , J. S. Ross
    • , A. B. Zylstra
    • , R. P. Drake
    • , D. H. Froula
    • , G. Gregori
    • , N. L. Kugland
    • , C. C. Kuranz
    • , M. C. Levy
    • , C. K. Li
    • , J. Meinecke
    • , T. Morita
    • , R. Petrasso
    • , C. Plechaty
    • , B. A. Remington
    • , D. D. Ryutov
    • , Y. Sakawa
    • , A. Spitkovsky
    • , H. Takabe
    •  & H.-S. Park
  • Letter |

    Topological charges form readily at defects in liquid crystals, but controlling them is a formidable task. An innovative approach pins defects to a microfibre, enabling controlled creation and manipulation of topological charges.

    • Maryam Nikkhou
    • , Miha Škarabot
    • , Simon Čopar
    • , Miha Ravnik
    • , Slobodan Žumer
    •  & Igor Muševič

Articles

  • Article |

    The Higgs mechanism is best known for generating mass for subatomic particles. Less well-known is that the idea originated in the study of superconductivity, and can be tested in the laboratory.

    • Daniel Sherman
    • , Uwe S. Pracht
    • , Boris Gorshunov
    • , Shachaf Poran
    • , John Jesudasan
    • , Madhavi Chand
    • , Pratap Raychaudhuri
    • , Mason Swanson
    • , Nandini Trivedi
    • , Assa Auerbach
    • , Marc Scheffler
    • , Aviad Frydman
    •  & Martin Dressel
  • Article |

    The Jarzynski equality, relating non-equilibrium processes to free-energy differences between equilibrium states, has been verified in a number of classical systems. An ion-trap experiment now succeeds in demonstrating its quantum counterpart.

    • Shuoming An
    • , Jing-Ning Zhang
    • , Mark Um
    • , Dingshun Lv
    • , Yao Lu
    • , Junhua Zhang
    • , Zhang-Qi Yin
    • , H. T. Quan
    •  & Kihwan Kim

Futures

  • Futures |

    It's no game.

    • David G. Blake

Corrigendum

  • Corrigendum |

    • Robert W. Style
    • , Rostislav Boltyanskiy
    • , Benjamin Allen
    • , Katharine E. Jensen
    • , Henry P. Foote
    • , John S. Wettlaufer
    •  & Eric R. Dufresne

Insight

  • Insight |

    Nature Physics Insight — Non-equilibrium physics

    Efforts to probe the physics of systems removed from equilibrium date back to Maxwell himself. But recent progress has renewed interest in the endeavour — a trend highlighted by this Insight, collecting key advances from across the research spectrum.