A description of the terminology and methodology used in this supplement, and a guide to the functionality available free online at natureindex.com.

A look at the inputs that result in high scientific research outputs.

The two US cities have a peerless partnership for life sciences.

Sizing up the success of the world’s science hotspots.

In a commentary on high-impact research outputs across 245 cities, György Csomós, Zsófia Viktória Vida and Balázs Lengyel explore changing patterns.

China’s powerhouse holds firm as the number one city in the Nature Index.

A large volume of charcoal sold in Europe comes from tropical forests and is often incorrectly labelled, raising questions about whether it was logged illegally.

Genetics reveals which Vikings went where during the influential Viking Age. Plus, how to get a COVID-19 vaccine to those who need it most and what happens when you read a paper every single day.

Despite our intimate familiarity with fire, we still struggle with a complete understanding of it. Plus, fast antigen coronavirus tests and increasingly impenetrable papers.

We derive the AdS5×S5 Green-Schwarz superstring from four-dimensional Beltrami-Chern-Simons theory reduced on a manifold with singular boundary conditions. In this construction, the Lax connection and spectral parameter of the integrable superstring have a simple geometric origin in four dimensions as gauge connection and reduction coordinate. κ symmetry arises as a certain class of singular gauge

DIY COVID-19 vaccines raise legal and ethical questions.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

SARS-CoV-2 infection is initiated by virus binding to ACE2 cell surface receptors1–4, followed by fusion of virus and cell membranes to release the virus genome into the cell. Both receptor binding and membrane fusion activities are mediated by the virus Spike glycoprotein, S5–7. As with other class I membrane fusion proteins, S is post-translationally cleaved, in this case by furin, into S1 and S2

A new type of peptide produces pain so intense that sometimes even morphine cannot quell it.

Advisory groups around the world release guidance to prioritize healthcare workers and others.

We have not met any of the biodiversity targets agreed in 2010 — but there are hopeful signs to build on. Plus, how COVID-19 can damage the brain and a visually sumptuous tour of the latest dinosaur discoveries.

In science news around the world, President Donald Trump admits he knew in February that the coronavirus that causes COVID-19 was "deadly," even as he publicly called the disease no worse than the seasonal flu. Scientists study the long-term health consequences of smoke from record wildfires on the U.S. West Coast. The virus that causes African swine fever, deadly to pigs, is discovered in Germany

We report instability of a superheated granular layer when a droplet is deposited on top of the layer. We find that the instability caused by evaporating vapor may trap or cause the droplet to sail away from the deposited position. The sailing motion is triggered by an unstable pressure distribution originated from fast fluidization of metallic grains. We provide a predictive model and experimental

Multiorbital systems such as the iron-based superconductors provide a new avenue to attack the longstanding problem of superconductivity in strongly correlated systems. In this work we study the superconductivity driven by a generic bosonic mechanism in a multiorbital model including the full dynamical electronic correlations induced by the Hubbard U and the Hund’s coupling. We show that superconductivity

Symmetry-breaking dynamical phase transitions (DPTs) abound in the fluctuations of nonequilibrium systems. Here we show that the spectral features of a particular class of DPTs exhibit the fingerprints of the recently discovered time-crystal phase of matter. Using Doob’s transform as a tool, we provide a mechanism to build classical time-crystal generators from the rare event statistics of some driven

The hyperfine structures of the 23S1 states of the 6Li+ and 7Li+ ions are investigated theoretically to extract the Zemach radii of the 6Li and 7Li nuclei by comparing with precision measurements. The obtained Zemach radii are larger than the previous values of Puchalski and Pachucki [] and disagree with them by about 1.5 and 2.2 standard deviations for 6Li and 7Li, respectively. Furthermore, our Zemach

With density functional molecular dynamics simulations, we computed the phase diagram of MgO from 50 to 2000 GPa up to 20000 K. Via thermodynamic integration (TDI), we derive the Gibbs free energies of the B1, B2, and liquid phases and determine their phase boundaries. With TDI and a pseudo-quasi-harmonic approach, we show that anharmonic effects are important and stabilize the B1 phase in particular

Selective excitation of a diffusive system’s transmission eigenchannels enables manipulation of its internal energy distribution. The fluctuations and correlations of the eigenchannels’ spatial profiles, however, remain unexplored so far. Here we show that the depth profiles of high-transmission eigenchannels exhibit low realization-to-realization fluctuations. Furthermore, our experimental and numerical

A universal quantum processor is a device that takes as input a (quantum) program, containing an encoding of an arbitrary unitary gate, and a (quantum) data register, on which the encoded gate is applied. While no perfect universal quantum processor can exist, approximate processors have been proposed in the past two decades. A fundamental open question is how the size of the smallest quantum program

As a result of non-equilibrium forces, purely repulsive self-propelled particles undergo macro-phase separation between a dense and a dilute phase. We present a thorough study of the ordering kinetics of such Motility-Induced Phase Separation (MIPS) in Active Brownian Particles in two-dimensions, and we show that it is generically accompanied by micro-phase separation. The growth of the dense phase

We present the results of an all-sky search for continuous gravitational wave signals with frequencies in the 500-1700,Hz range targeting neutron stars with ellipticity of 10−8. The search is done on LIGO O2 data using the Falcon analysis pipeline. The results presented here double the sensitivity over any other result on the same data . The search is capable of detecting low ellipticity sources up

Axion dark matter (DM) may convert to radio-frequency electromagnetic radiation in the strong magnetic fields around neutron stars. The radio signature of such a process would be an ultra-narrow spectral peak at a frequency determined by the mass of the axion particle. We analyze data we collected from the Robert C. Byrd Green Bank Telescope in the L-band and the Effelsberg 100-m Telescope in the L-Band

Controlling magnetism, essential for a wide-range of technologies, is impaired by the impossibility of generating a maximum of magnetic field in free space. Here, we propose a strategy based on negative permeability to overcome this stringent limitation. We experimentally demonstrate that an active magnetic metamaterial can emulate the field of a straight current wire at a distance. Our strategy leads

At low temperature, collective excitations of one-dimensional (1D) interacting fermions exhibit spin-charge separation, a unique feature predicted by the Tomonaga-Luttinger liquid (TLL) theory, but a rigorous understanding remains challenging. Using the thermodynamic Bethe Ansatz (TBA) formalism, we analytically derive universal properties of a 1D repulsive spin-1/2 Fermi gas with arbitrary interaction

The gyroid lattice is a metamaterial which allows chirality that is tunable by geometry. Gyroid lattices were made in chiral and non-chiral form by 3D printing. The chiral lattices exhibited nonclassical elastic effects including coupling between compressive stress and torsional deformation. Gyroid lattices can approach upper bounds on elastic modulus. Effective modulus is increased by distributed

Information is physical but information is also processed in finite time. Where computing protocols are concerned, finite-time processing in the quantum regime can dynamically generate coherence. Here we show that this can have significant thermodynamic implications. We demonstrate that quantum coherence generated in the energy eigenbasis of a system undergoing a finite-time information erasure protocol

The characterization of quantum features in large Hilbert spaces is a crucial requirement for testing quantum protocols. In the continuous variables encoding, quantum homodyne tomography requires an amount of measurements that increases exponentially with the number of involved modes, which practically makes the protocol intractable even with few modes. Here we introduce a new technique, based on a

Several studies about to start will explore whether near-infrared (NIR) light can improve symptoms of Parkinson's disease—including a study in France in which a fiber optic cable implanted in patients' brains will deliver NIR directly to the substantia nigra, a region that degenerates in Parkinson's disease. Animal models and small tests in people have suggested benefits, but some mainstream Parkinson's

Motivated by non-zero neutrino masses and the possibility of New Physics discovery, a number of experiments search for neutrinoless double beta decay. While hunting for this hypothetical nuclear process, a significant amount of two-neutrino double beta decay data has become available. Although these events are regarded and studied mostly as the background of neutrinoless double beta decay, they can

We describe a new mechanism of dark matter production. If dark matter particles acquire mass during a first order phase transition, it is energetically unfavourable for them to enter the expanding bubbles. Instead, most of them are reflected and quickly annihilate away. The bubbles eventually merge as the phase transition completes and only the dark matter particles which have entered the bubbles survive

Matrix Product States (MPS) and Projected Entangled Pair States (PEPS) are powerful analytical and numerical tools to assess quantum many-body systems in one and higher dimensions, respectively. While MPS are comprehensively understood, in PEPS fundamental questions, relevant analytically as well as numerically, remain open, such as how to encode symmetries in full generality, or how to stabilize numerical

A massive new study of DNA sequences from Viking Age burials around Europe presents the story of the Vikings written in genes. The results, published this week in Nature, trace how the Vikings radiated across Europe from their Scandinavian homeland, and how people with roots elsewhere also took up Viking ways, making "Viking" a job description, not a matter of heredity. Researchers gathered human remains

A major report card on the state of biodiversity gives failing grades to the world's nations. The United Nations's Global Biodiversity Outlook 5, released this week, concludes the world has not met ambitious targets set 10 years ago to protect nature. The new assessment finds some bright spots, such as a substantial rise in the extent of protected areas. But only six of the U.N. Convention on Biological