Quantum physics articles within Nature Communications

Featured

  • Article |

    Graphene and InAs nanowires are both promising materials for coherent spin manipulation, but coupling between a quantum system and its environment leads to decoherence. Here, the contribution of electron–phonon coupling to decoherence in graphene and InAs nanowire is studied.

    • P. Roulleau
    • , S. Baer
    •  & T. Ihn
  • Article
    | Open Access

    Multimode interference devices could allow the implementation of multiport circuits for quantum technologies. Here, quantum interference is demonstrated in 2×2 and 4×4 multimode interference devices, and a technique is reported to characterize such devices.

    • Alberto Peruzzo
    • , Anthony Laing
    •  & Jeremy L. O'Brien
  • Article |

    Quantum-enhanced measurements use quantum mechanical effects to enhance measurement sensitivity of classical quantities; but the required quantum states are generally highly entangled and difficult to produce. In this study, the use of entangled states is avoided allowing Heisenberg-limited measurements.

    • Daniel Braun
    •  & John Martin
  • Article |

    The nonlocality of a quantum state is often difficult to predict. Here, Cavalcanti and colleagues devise a method based on networks that makes this characterization much easier, revealing that the nonlocality of a quantum state depends on the context of the measurement.

    • Daniel Cavalcanti
    • , Mafalda L. Almeida
    •  & Antonio Acín
  • Article |

    Error correction in quantum computing can be implemented using transversal gates, which in turn rely on the availability of so-called magic states. The authors experimentally show that it is possible to improve the fidelity of these states by distilling five of them into one.

    • Alexandre M. Souza
    • , Jingfu Zhang
    •  & Raymond Laflamme
  • Article |

    Direct quantum state tomography—deducing the state of a system from measurements—is mostly unfeasible due to the exponential scaling of measurement number with system size. The authors present two new schemes, which scale linearly in this respect, and can be applied to a wide range of quantum states.

    • Marcus Cramer
    • , Martin B. Plenio
    •  & Yi-Kai Liu
  • Article |

    Two principles have recently been proposed as attempts to provide physical axioms for quantum mechanics: causality and macroscopic locality. Cavalcanti and colleagues show here that the two are not equivalent, giving confidence in information causality as a constraint for correlations obtained in experiments.

    • Daniel Cavalcanti
    • , Alejo Salles
    •  & Valerio Scarani
  • Article
    | Open Access

    Molecular fluctuations are a source of noise that can impede single-molecule identification. Here, quantum-fluctuation-induced inelastic noise is observed as current fluctuations in individual molecules, suggesting that inelastic noise could be used as a molecular signature.

    • Makusu Tsutsui
    • , Masateru Taniguchi
    •  & Tomoji Kawai
  • Article
    | Open Access

    Signal processing by time reversal has thus far only been realized through nonlinear mechanisms. The authors describe an all-linear, and thus low-power, time-reversal process based on frequency inversion in a dynamically controlled artificial periodic structure, a dynamic magnonic crystal.

    • Andrii V. Chumak
    • , Vasil S. Tiberkevich
    •  & Burkard Hillebrands
  • Review Article |

    Gravitational waves are predicted by general relativity, but their direct observation from astronomical sources hinges on large improvements in detection sensitivity. The authors review how squeezed light and other quantum optical concepts are being applied in the development of next generation interferometric detectors.

    • Roman Schnabel
    • , Nergis Mavalvala
    •  & Ping K. Lam
  • Article |

    In low-temperature one-dimensional metals, electrons condense into collective charge-density wave states. Zybtsevet al. observe conductivity jumps with temperature in a metal bar, as only specific wavelengths are permitted in the bar for the charge-density wave modes.

    • S.G. Zybtsev
    • , V.Ya. Pokrovskii
    •  & S.V. Zaitsev-Zotov
  • Article |

    Routing packets on the growing and changing underlying structure of the Internet is challenging and currently based only on local connectivity. Here, a global Internet map is devised: with a greedy forwarding algorithm, it is robust with respect to network growth, and allows speeds close to the theoretical best.

    • Marián Boguñá
    • , Fragkiskos Papadopoulos
    •  & Dmitri Krioukov
  • Article |

    Electrons in metals at extremely high magnetic fields show interesting quantum structures. The authors measure the angle-dependent Nernst effect with high precision and show that, for bismuth, Coulomb interactions between the electrons become important in this ultraquantum regime.

    • Huan Yang
    • , Benoît Fauqué
    •  & Kamran Behnia
  • Article |

    The magnetic flux lines in a superconductor present intricate patterns, whose origins are seldom understood. Here the authors link them to geometrical effects by means of the 'hairy ball' theorem, which states that for a vector field on a sphere there will always be at least one singularity.

    • Mark Laver
    •  & Edward. M. Forgan
  • Article |

    Quantum communication applications require memories capable of storing multiple qubits. To implement scalable architectures for this purpose, Usmani and coworkers turn to a rare-earth doped silicate, in which they demonstrate coherent and reversible mapping of 64 optical modes at the single photon level.

    • Imam Usmani
    • , Mikael Afzelius
    •  & Nicolas Gisin