Physics articles within Nature Physics

Featured

  • Letter |

    Hilbert space is made up of a potentially infinite number of dimensions that correspond to all the parameters needed to fully define a system. The idea is seen as an important resource for quantum information processing. A technique for estimating the number of dimensions in an unknown system based on the results of measurements performed on it—a so-called dimension witness—is now experimentally demonstrated.

    • Johan Ahrens
    • , Piotr Badzia̧g
    •  & Mohamed Bourennane

  • Letter |

    Is it possible to deduce the number of dimensions of a completely unknown system only from the results of measurements performed on it? So-called dimension witnesses allow such an estimation, and are now experimentally demonstrated using pairs of entangled photons.

    • Martin Hendrych
    • , Rodrigo Gallego
    •  & Juan P. Torres

  • Letter |

    Uranium ruthenium silicide exhibits a discontinuity in its specific heat at 17.5 K. The underlying cause of this anomaly is hotly debated. A first-principles study of high-order correlations in its electronic structure suggests this behaviour is the result of the emergence of rank-5 nematic order.

    • Hiroaki Ikeda
    • , Michi-To Suzuki
    •  & Yuji Matsuda

  • Article |

    There is growing evidence that quantum coherence enhances energy transfer through individual photosynthetic light-harvesting protein complexes. This idea is now extended to complicated networks of such proteins and chemical reaction centres. A mathematical analysis reveals that coherence lengths up to 5 nm are possible.

    • A. K. Ringsmuth
    • , G. J. Milburn
    •  & T. M. Stace

  • Article |

    A demonstration of the ability to transmit spin currents over distances of more than one hundred micrometres with an efficiency of up to 75% in graphene grown epitaxially on silicon carbide improves the prospects of graphene-based spintronic devices.

    • Bruno Dlubak
    • , Marie-Blandine Martin
    •  & Albert Fert

  • Letter |

    You influence a system by measuring it. This back-action is an important consideration when studying tiny structures in which quantum effects play a crucial role. Researchers now show that quantum interference could provide a way to negate back-action in quantum-dot-qubit circuits.

    • G. Granger
    • , D. Taubert
    •  & A. S. Sachrajda

  • News & Views |

    The quantum spin Hall effect is predicted to be the result of two oppositely polarized spin currents travelling in opposite directions around the edges of a topological insulator. But only now has the spin polarization of these currents been confirmed.

    • Yi Zhou
    •  & Fu-Chun Zhang

  • News & Views |

    A study shows that controlling link dynamics on a network is distinctly different from controlling the dynamics of its nodes. This development illustrates how ideas from control-systems engineering can help us better understand the organization of complex systems.

    • Jean-Jacques Slotine
    •  & Yang-Yu Liu

  • Article |

    The quantum spin Hall state is predicted to consist of two oppositely polarized spin currents travelling in opposite directions around the edges of a topological insulator. Non-local measurements of the transport in HgTe quantum wells confirm the polarized nature of these edge states.

    • Christoph Brüne
    • , Andreas Roth
    •  & Shou-Cheng Zhang

  • Article |

    Surprisingly little is known about how network dynamics might be controlled, despite extensive research into how they behave. A study of the controllability of network edge dynamics reveals that it differs from that of nodal dynamics, and that real-world networks are easier to control than their random counterparts.

    • Tamás Nepusz
    •  & Tamás Vicsek

  • Letter |

    A quantum memory that combines high-efficiency and long lifetime is now demonstrated. Employing a collective excitation, or spin wave, in an ensemble of atoms in a trap improves memory lifetime, while incorporating the trap into an optical ring cavity simultaneously aids higher retrieval efficiency.

    • Xiao-Hui Bao
    • , Andreas Reingruber
    •  & Jian-Wei Pan

  • Article |

    Diffraction of matter waves from crystalline structures has long been used to characterize underlying spatial order. The same principle offers a valuable—and potentially non-destructive—tool for probing the strongly correlated phases of ultracold atoms confined to optical lattices.

    • Bryce Gadway
    • , Daniel Pertot
    •  & Dominik Schneble

  • Letter |

    The penetration of a superconducting current from a superconductor into a half-metallic ferromagnet is usually forbidden. Resonances in the conductance spectra of superconductor/half-metal heterostructures suggest this restriction is lifted by the occurrence of unconventional equal-spin Andreev reflection.

    • C. Visani
    • , Z. Sefrioui
    •  & Javier E. Villegas

  • Article |

    The extra states sometimes observed in graphene’s quantum Hall characteristics have been presumed to be the result of broken SU(4) symmetry. Magnetotransport measurements of high-quality graphene in a tilted magnetic field finally prove this is indeed the case.

    • A. F. Young
    • , C. R. Dean
    •  & P. Kim

  • News & Views |

    Do quantum states offer a faithful representation of reality or merely encode the partial knowledge of the experimenter? A new theorem illustrates how the latter can lead to a contradiction with quantum mechanics.

    • Scott Aaronson

  • News & Views |

    Quantum non-locality can improve the quality of sources of randomness.

    • Serge Massar

  • Article |

    A no-go theorem on the reality of the quantum state is demonstrated. If the quantum state merely represents information about the physical state of a system, then predictions that contradict those of quantum theory are obtained.

    • Matthew F. Pusey
    • , Jonathan Barrett
    •  & Terry Rudolph

  • Letter |

    Bell’s equations enable scientists to test the fundamental implications of quantum physics. A central tenet of this idea is that the choice of measurement is truly random. Researchers now show that some Bell experiments can even increase randomness in cases where choice is not entirely free. The concept could increase the usefulness of weakly random sources for more thorough tests of quantum mechanics.

    • Roger Colbeck
    •  & Renato Renner

  • Research Highlights |

    • Iulia Georgescu

  • News & Views |

    Biological systems can adapt to changes in their environment over a wide range of conditions, but responding quickly and accurately is energetically costly. A study pins down the relationship between energy, speed and accuracy.

    • Pieter Rein ten Wolde

  • News & Views |

    The energy gap associated with Cooper pair formation in unconventional superconductors can fall to zero along lines of the Fermi surface. Differences in the shape and location of these lines bear information on the interaction that triggers Cooper pair formation.

    • Dung-Hai Lee

  • Editorial |

    Controversial and out-of-line results should not be discarded or hidden — even though revealing them may come at some recriminatory cost, as the OPERA collaboration has discovered.

  • News & Views |

    Two experiments have measured an all-important number in neutrino physics. Going by the innocuous name of 'θ13', this parameter's value has significant implications for our understanding of the Universe.

    • David Wark

  • Article |

    Small clusters of magnetic atoms can behave in very different ways to those same atoms in bulk. Arranging iron atoms one by one into complex but well-defined patterns on a copper surface enables the construction of nanoscale magnetic structures with tailored characteristics.

    • Alexander Ako Khajetoorians
    • , Jens Wiebe
    •  & Roland Wiesendanger

  • Article |

    In 2000, Asher Peres put forward the paradoxical idea that entanglement could be produced after the entangled particles have been measured, even if they no longer exist. Researchers now experimentally demonstrate this idea using four photons.

    • Xiao-song Ma
    • , Stefan Zotter
    •  & Anton Zeilinger

  • Letter |

    The proximity effect enables the injection of Cooper pairs from a superconductor into a normal metal, but they usually do not travel far into the metal. A study of the propagation of Cooper pairs from irregularly shaped superconducting islands on a metal film finds that they can travel further than expected for certain island geometries.

    • Jungdae Kim
    • , Victor Chua
    •  & Chih-Kang Shih

  • Letter |

    Despite their name, the bulk electrical conductivity of most topological insulators is relatively high, masking many of the important characteristics of its protected, surface conducting states. Counter-doping reduces the bulk conductivity of Bi2Se3 significantly, allowing these surface states and their properties to be clearly identified.

    • Dohun Kim
    • , Sungjae Cho
    •  & Michael S. Fuhrer

  • Letter |

    An interferometric implementation of Young’s double-slit experiment is used to probe quantum correlations that are manifest in the distribution of local spin fluctuations in a two-component degenerate Fermi gas.

    • Jakob Meineke
    • , Jean-Philippe Brantut
    •  & Tilman Esslinger

  • Letter |

    Bose–Einstein condensation is usually considered to be an inherently quantum mechanical phenomenon. An observation of the condensation in a classical system of light waves in a nonlinear crystal demonstrates that it is a general wave-mechanical phenomenon.

    • Can Sun
    • , Shu Jia
    •  & Jason W. Fleischer

  • Editorial |

    In times of fiscal restraint, it is vital that every dollar, pound, yen, yuan and euro be put to good use. Lazy accounting, however, is no way to encourage excellence.

  • Commentary |

    The long-term promises of quantum simulators are far-reaching. The field, however, also needs clearly defined short-term goals.

    • J. Ignacio Cirac
    •  & Peter Zoller

Browse broader subjects

Browse narrower subjects

Browse Physics across other nature.com journals