Volume 17

  • No. 11 November 2021

    Neutron structure oscillates

    Form factors encode the structure of nucleons. Measurements from electron–positron annihilation at BESIII reveal an oscillating behaviour of the neutron electromagnetic form factor, and clarify a long-standing photon–nucleon interaction puzzle.

    See The BESIII Collaboration and Pakhlova

  • No. 10 October 2021

    Topological frequency combs

    Optical frequency combs are a key technology in communications, sensing and metrology. A theoretical proposal shows that introducing topological principles into their design makes on-chip combs more efficient and robust against fabrication defects.

    See Mittal et al. and Peano

  • No. 9 September 2021

    Self-propelled by surface phase transitions

    A class of synthetic microswimmer self-assembled from alkane oil drops in surfactant solution offers a rechargeable platform for studying how microorganisms exploit flagellar elasticity to move.

    See Cholakova et al. and Ramananarivo

  • No. 8 August 2021

    Nanoscale nematicity

    High-temperature superconductor Fe(Te,Se) transitions to an electronic nematic phase that breaks rotation symmetry of the lattice near the composition where the superconducting transition temperature reaches its peak. Scanning tunnelling microscopy reveals that this transition is characterized by the emergence of nanoscale nematic regions. These regions, observed as unidirectional modulations portrayed in the image, show a surprising suppression of superconductivity.

    See Zhao et al.

  • No. 7 July 2021

    Biomolecules catch a wave

    Protein oscillations linked to cell division in Escherichia coli are shown to localize unrelated molecules on the cell membrane via a diffusiophoretic mechanism, in which an effective friction fosters cargo transport along the fluxes set up by the proteins.

    See Ramm et al. and Bocquet and Palacci

  • No. 6 June 2021

    A twisted topological laser

    A topological photonic crystal design generates light that carries orbital angular momentum with high quantum numbers. The beam contains several different states at the same time, promising integrated and multiplexed light sources. The image represents the self-interference of a beam with a quantum number of 156.

    See Bahari et al. and Ma

  • No. 5 May 2021

    Incoherent quantum holography

    By exploiting polarization entanglement between photons, quantum holography can circumvent the need for the first-order coherence required for classical holographic imaging. In this protocol, when one photon in an entangled pair is directed at a smiley-shaped object, the phase information of the object is instantaneously shared with the other photon, regardless of their separation. The object shape is then remotely reconstructed in the form of quantum holograms by detecting photons with separate cameras.

    See Defienne et al.

  • No. 4 April 2021

    Phase separation in the nucleus

    Biomolecules in the cell nucleus form condensates at a rate slower than that predicted by the theory of droplet growth. Experiments on living cells attribute this anomalous coarsening behaviour to subdiffusive dynamics in the crowded nucleus. The image is a composite fluorescence micrograph of live human osteosarcoma cells, showing the co-localization of nuclear droplets and chromatin, using a spinning disk confocal microscope.

    Brangwynne, Article

  • No. 3 March 2021

    The formation of a shell

    Molluscs are capable of assembling layers of material in the shells around them with exquisite control. Synchrotron-based nanotomographic imaging of the structural evolution of this layer formation has now prompted a model that draws analogy with topological defect dynamics in liquid crystals

    Article → N&V

  • No. 2 February 2021

    When networks get real

    Combining concepts from knot theory and statistical mechanics leads to a method for distinguishing between physical networks with identical wiring but different layouts.

    See Barabási et al.

  • No. 1 January 2021

    Arrow of Time

    In 1927, Sir Arthur Eddington coined the phrase ‘time’s arrow’ to express the fact that the time reversibility of events on a microscale does not necessarily exist in macroscopic processes, for which we can usually discern temporal order. Now, a machine learning algorithm trained to infer the direction of time’s arrow has identified entropy production as key to making this decision.

    Seif, Article