Letters

  • Letter |

    The organization of small clusters of connected cells confined to an egg chamber during early development can be mapped onto a tree packing problem. Entropically preferred packing configurations are shown to arise more readily in experiment.

    • Jasmin Imran Alsous
    • , Paul Villoutreix
    • , Norbert Stoop
    • , Stanislav Y. Shvartsman
    •  & Jörn Dunkel
  • Letter |

    Calculating the amount of radiation that can ultimately be extracted from free electrons near an arbitrary material structure is a challenge. Now, an upper limit to the spontaneous photon emission of electrons is demonstrated, regardless of geometry.

    • Yi Yang
    • , Aviram Massuda
    • , Charles Roques-Carmes
    • , Steven E. Kooi
    • , Thomas Christensen
    • , Steven G. Johnson
    • , John D. Joannopoulos
    • , Owen D. Miller
    • , Ido Kaminer
    •  & Marin Soljačić
  • Letter |

    A neutron scattering study of the three-dimensional antiferromagnet Cu3TeO6 uncovers evidence for topological crossings in the magnon spectra of this system.

    • Weiliang Yao
    • , Chenyuan Li
    • , Lichen Wang
    • , Shangjie Xue
    • , Yang Dan
    • , Kazuki Iida
    • , Kazuya Kamazawa
    • , Kangkang Li
    • , Chen Fang
    •  & Yuan Li
  • Letter |

    Transport measurements performed on MoGe superconducting nanowires reveal a quantitative agreement with quantum critical behaviour driven by a pair-breaking mechanism.

    • Hyunjeong Kim
    • , Frédéric Gay
    • , Adrian Del Maestro
    • , Benjamin Sacépé
    •  & Andrey Rogachev
  • Letter |

    The authors theoretically investigate a novel form of a Doppler effect in homogeneous systems with positive refractive index that occurs under certain conditions. It is suggested that this Doppler effect can be experimentally separated from other Doppler effects by using polaritons such as those found in graphene.

    • Xihang Shi
    • , Xiao Lin
    • , Ido Kaminer
    • , Fei Gao
    • , Zhaoju Yang
    • , John D. Joannopoulos
    • , Marin Soljačić
    •  & Baile Zhang
  • Letter |

    The state of a superconducting circuit qubit governs the photonic heat flow through an integrated assembly, constituting a quantum heat valve that provides a testbed for exploring quantum thermodynamics in a circuit quantum electrodynamics setting.

    • Alberto Ronzani
    • , Bayan Karimi
    • , Jorden Senior
    • , Yu-Cheng Chang
    • , Joonas T. Peltonen
    • , ChiiDong Chen
    •  & Jukka P. Pekola
  • Letter |

    Optoelectronic experiments show that a monolayer of WTe2 is a material that simultaneously has topological electronic states and electron wavefunctions with a dipole in their Berry curvature.

    • Su-Yang Xu
    • , Qiong Ma
    • , Huitao Shen
    • , Valla Fatemi
    • , Sanfeng Wu
    • , Tay-Rong Chang
    • , Guoqing Chang
    • , Andrés M. Mier Valdivia
    • , Ching-Kit Chan
    • , Quinn D. Gibson
    • , Jiadong Zhou
    • , Zheng Liu
    • , Kenji Watanabe
    • , Takashi Taniguchi
    • , Hsin Lin
    • , Robert J. Cava
    • , Liang Fu
    • , Nuh Gedik
    •  & Pablo Jarillo-Herrero
  • Letter |

    Laser cooling of optically trapped diatomic molecules CaF to sub-Doppler temperatures has been achieved. The technique provides an alternative approach towards the production of ultracold polar molecules.

    • Loïc Anderegg
    • , Benjamin L. Augenbraun
    • , Yicheng Bao
    • , Sean Burchesky
    • , Lawrence W. Cheuk
    • , Wolfgang Ketterle
    •  & John M. Doyle
  • Letter |

    By coupling photons in two distinguishable modes to separate transitions of a single atom, strong correlations between photons are created. The technique makes all-optical switching and sensing possible at the single-photon level.

    • Christoph Hamsen
    • , Karl Nicolas Tolazzi
    • , Tatjana Wilk
    •  & Gerhard Rempe
  • Letter |

    Spins are transmitted over a distance of 5 μm through a piece of antiferromagnetic graphene. This shows that graphene can be a platform to explore the fundamental physics of spin transport in antiferromagnets for application in spintronics.

    • Petr Stepanov
    • , Shi Che
    • , Dmitry Shcherbakov
    • , Jiawei Yang
    • , Ruoyu Chen
    • , Kevin Thilahar
    • , Greyson Voigt
    • , Marc W. Bockrath
    • , Dmitry Smirnov
    • , Kenji Watanabe
    • , Takashi Taniguchi
    • , Roger K. Lake
    • , Yafis Barlas
    • , Allan H. MacDonald
    •  & Chun Ning Lau
  • Letter |

    Magnetically tunable scattering resonances between strontium and rubidium atoms are observed in an ultracold experiment, opening the door to exploring quantum many-body physics with new designed molecules.

    • Vincent Barbé
    • , Alessio Ciamei
    • , Benjamin Pasquiou
    • , Lukas Reichsöllner
    • , Florian Schreck
    • , Piotr S. Żuchowski
    •  & Jeremy M. Hutson
  • Letter |

    A superlattice consisting of SrIrO3 and SrTiO3 is shown to display a giant response to sub-tesla external magnetic fields—a direct consequence of its antiferromagnetic nature.

    • Lin Hao
    • , D. Meyers
    • , Hidemaro Suwa
    • , Junyi Yang
    • , Clayton Frederick
    • , Tamene R. Dasa
    • , Gilberto Fabbris
    • , Lukas Horak
    • , Dominik Kriegner
    • , Yongseong Choi
    • , Jong-Woo Kim
    • , Daniel Haskel
    • , Philip J. Ryan
    • , Haixuan Xu
    • , Cristian D. Batista
    • , M. P. M. Dean
    •  & Jian Liu
  • Letter |

    Origami-inspired metamaterial design gives rise to structures with kinematic properties dictated by the topology of their configuration space. The approach allows for well-defined metamaterial properties even in the presence of unpredictable forces.

    • Bin Liu
    • , Jesse L. Silverberg
    • , Arthur A. Evans
    • , Christian D. Santangelo
    • , Robert J. Lang
    • , Thomas C. Hull
    •  & Itai Cohen
  • Letter |

    Long-range ferromagnetic order in co-doped topological insulator thin films and their typical ferromagnetic domain behaviour is directly evidenced by low-temperature magnetic force microscopy.

    • Wenbo Wang
    • , Yunbo Ou
    • , Chang Liu
    • , Yayu Wang
    • , Ke He
    • , Qi-Kun Xue
    •  & Weida Wu
  • Letter |

    An off-resonant radiofrequency modulation scheme applied to a strongly interacting superfluid Fermi gas reveals the presence of a Higgs mode — an oscillation of the amplitude of the superconducting order parameter.

    • A. Behrle
    • , T. Harrison
    • , J. Kombe
    • , K. Gao
    • , M. Link
    • , J.-S. Bernier
    • , C. Kollath
    •  & M. Köhl
  • Letter |

    A neutron scattering study of an Ising-like quasi-one-dimensional antiferromagnet, BaCo2V2O8, reveals a topological quantum phase transition when it is subjected to a transverse magnetic field.

    • Quentin Faure
    • , Shintaro Takayoshi
    • , Sylvain Petit
    • , Virginie Simonet
    • , Stéphane Raymond
    • , Louis-Pierre Regnault
    • , Martin Boehm
    • , Jonathan S. White
    • , Martin Månsson
    • , Christian Rüegg
    • , Pascal Lejay
    • , Benjamin Canals
    • , Thomas Lorenz
    • , Shunsuke C. Furuya
    • , Thierry Giamarchi
    •  & Béatrice Grenier
  • Letter |

    α-RuCl3, a promising candidate to realize the Kitaev model, has attracted great interest recently. Two types of fractional excitation—gauge fluxes and Majorana fermions—are observed, which contribute to the spin excitation gap in different ways.

    • Nejc Janša
    • , Andrej Zorko
    • , Matjaž Gomilšek
    • , Matej Pregelj
    • , Karl W. Krämer
    • , Daniel Biner
    • , Alun Biffin
    • , Christian Rüegg
    •  & Martin Klanjšek
  • Letter |

    A detailed and systematic neutron scattering study of rare-earth pyrochlore magnet Pr2Hf2O7 provides evidence for a quantum spin ice state, and emergent lattice quantum electrodynamics consistent with theoretical predictions.

    • Romain Sibille
    • , Nicolas Gauthier
    • , Han Yan
    • , Monica Ciomaga Hatnean
    • , Jacques Ollivier
    • , Barry Winn
    • , Uwe Filges
    • , Geetha Balakrishnan
    • , Michel Kenzelmann
    • , Nic Shannon
    •  & Tom Fennell
  • Letter |

    A new type of exciton is observed in transition-metal dichalcogenide heterobilayers that is indirect in both real space and momentum space. It consists of a paired electron in MoS2 at the K point and hole spread across MoS2 and WSe2 at the Γ point.

    • Jens Kunstmann
    • , Fabian Mooshammer
    • , Philipp Nagler
    • , Andrey Chaves
    • , Frederick Stein
    • , Nicola Paradiso
    • , Gerd Plechinger
    • , Christoph Strunk
    • , Christian Schüller
    • , Gotthard Seifert
    • , David R. Reichman
    •  & Tobias Korn
  • Letter |

    Sending quantum states as shaped microwave photonic wavepackets realizes on-demand, high-fidelity quantum state transfer and entanglement between two superconducting cavity quantum memories.

    • Christopher J. Axline
    • , Luke D. Burkhart
    • , Wolfgang Pfaff
    • , Mengzhen Zhang
    • , Kevin Chou
    • , Philippe Campagne-Ibarcq
    • , Philip Reinhold
    • , Luigi Frunzio
    • , S. M. Girvin
    • , Liang Jiang
    • , M. H. Devoret
    •  & R. J. Schoelkopf
  • Letter |

    Antiparallel streams of nematically oriented cells arise in both embryonic development and cancer. In vitro experiments and a hydrodynamic active gel theory suggest that these cells are subject to a transition that is driven by their activity.

    • G. Duclos
    • , C. Blanch-Mercader
    • , V. Yashunsky
    • , G. Salbreux
    • , J.-F. Joanny
    • , J. Prost
    •  & P. Silberzan
  • Letter |

    Light fields of energy comparable to the Coloumb field that binds valence electrons in atoms generate states where nearly free electrons oscillate in the laser field. These are now shown to exist in rare gases, acting as gain for laser filamentation.

    • Mary Matthews
    • , Felipe Morales
    • , Alexander Patas
    • , Albrecht Lindinger
    • , Julien Gateau
    • , Nicolas Berti
    • , Sylvain Hermelin
    • , Jérôme Kasparian
    • , Maria Richter
    • , Timm Bredtmann
    • , Olga Smirnova
    • , Jean-Pierre Wolf
    •  & Misha Ivanov
  • Letter |

    Experiments on the Shakti geometry of artificial spin ice show that its low-energy excitations are topologically protected, and that an emergent classical topological order influences the ergodicity and equilibration of this nanomagnetic system.

    • Yuyang Lao
    • , Francesco Caravelli
    • , Mohammed Sheikh
    • , Joseph Sklenar
    • , Daniel Gardeazabal
    • , Justin D. Watts
    • , Alan M. Albrecht
    • , Andreas Scholl
    • , Karin Dahmen
    • , Cristiano Nisoli
    •  & Peter Schiffer
  • Letter |

    The many phases of water ice continue to be fertile ground for surprising discoveries. This latest study reveals that ice II vanishes from the phase diagram of water upon the addition of small amounts of ammonium fluoride.

    • Jacob J. Shephard
    • , Ben Slater
    • , Peter Harvey
    • , Martin Hart
    • , Craig L. Bull
    • , Steven T. Bramwell
    •  & Christoph G. Salzmann