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A discovered letter explains the loss of key paragraphs during the translation of one of Georges Lemaître's papers about the expanding Universe, shows Mario Livio.

Astronomer Fred Hoyle supposedly coined the catchy term to ridicule the theory of the Universe’s origins — 75 years on, it’s time to set the record straight.

Despite huge breakthroughs, astronomers still can’t agree on what the cosmos is made of, much less how it came to be. A fresh account delves into the reasons.

Data collected from zoos and aquariums worldwide show that hormonal contraception or permanent surgical sterilization in mammals increase life expectancy, with different mechanisms in males and females.

Here, the authors find that mammals with more diverse immune genes (MHC I) face lower cancer risk, suggesting that immune surveillance could be a widespread natural defense against cancer.

Quantum information processing requires a system in which a single photon controls a single atom and vice versa. Here, the authors demonstrate such reciprocal operation and achieve coherent manipulation of a quantum dot by a few photons sent on an optical cavity.

Exciton–polaritons are bosonic quasi-particles resulting from strong coupling of excitons and photons but so far only their photon component had been resolved. Here, Menard et al. monitor the intra-excitonic transitions and study how a reservoir of optically dark excitons forms and feeds the degenerate state.

Genome-wide association analyses of intracranial and nine subcortical brain volumes in 74,898 participants of European ancestry identify 254 independent loci and yield polygenic scores accounting for brain variation across ancestries.

Quantum fluids such as cavity-polaritons show nonlinear optical properties of interest in applications such as quantum optics. Here, Sturm and colleagues demonstrate an optical control of the phase of a polariton flow, and make use of this to realize a compact exciton–polariton interferometer.

Bright and tunable single-photon sources are essential for future quantum technologies. Here, the authors deterministically couple a quantum dot to a pillar structure that enables application of electric fields to provide a tunable single-photon source with a demonstrated extraction efficiency of 53%.

For quantum technologies to become widespread and scalable, bright sources of indistinguishable single photons are essential. Through deterministic positioning of quantum dots in pillar cavities, Gazzano et al.present a solid-state single-photon source with brightness as large as 0.65 photons per pulse.

Coupled semiconductor microcavities constitute a model system where the hopping, interaction, and decay of exciton polaritons can be engineered. Here, Rodriguez et al. show how the phase acquired by polaritons hopping between cavities can be controlled through polariton-polariton interactions.

Recent numerical simulations indicate that well-defined topological defects arise in the dynamics of glasses. Here, the authors report the presence of topological defects in the vibrational eigenspace of an experimental two-dimensional colloidal glass.

Similar to atoms in cold gases, exciton–polaritons in semiconductor microcavities can undergo Bose–Einstein condensation, but under non-equilibrium conditions. Now, quantized vortices and persistent currents — hallmarks of superfluid behaviour — have been observed in such condensates.

Based on optically breaking time-reversal symmetry by spin polarizing a gain medium with a circularly polarized optical pump, an integrated scheme for controlling the chirality of orbital angular momentum lasing is demonstrated.

Topologically protected lasing is reported in a lattice of polariton micropillars.

Miniature optomechanical disks could be used as ultrafast and ultrasensitive fluidic sensors due to the combination of their high-frequency vibrations, small mass and low dissipation in liquids.

Li et al. introduced tract-geometry coupling (TGC) to quantify the coupling between white matter tracts and cortical geometry in the human brain, shedding light on how the brain’s wiring and shape evolve together and its support for behavior and growth.

Pioneering techniques could settle longstanding controversy about the accuracy of previous simulations.

Quantum emitters have recently been identified as efficient sources of graph states, which are entangled states crucial for photonic quantum computation. Here the authors demonstrate deterministic and reconfigurable generation of caterpillar graph states using a semiconductor quantum dot in a cavity.

The RNA-cleaving Cas13 degrades both host and bacteriophage transcripts, thereby rendering infected cells dormant and broadly resistant to phage-mediated lysis.

Genome-wide analysis identifies variants associated with the volume of seven different subcortical brain regions defined by magnetic resonance imaging. Implicated genes are involved in neurodevelopmental and synaptic signaling pathways.

Embrace mistakes, urges Mario Livio — they are portals to scientific progress.

Monoclonal antibodies show great promise in treating Covid-19 patients. Here, Maisonnasse, Aldon and colleagues report pre-clinical results for COVA1-18 and demonstrate that it reduces viral infectivity in three animal models with over 95% efficacy in macaques upper respiratory tract.

Evidence from large longitudinal neuroimaging cohorts, which include genetic and behavioral data, suggest a common neural basis for symptoms seen across multiple psychiatric disorders.

What is the link between the discovery of the relativistic expanding Universe and British imperialism? A public panel debate in the early days of relativistic cosmology shows how fundamental scientific research, whether there are obvious political stakeholders (like biosecurity and climate) or not, runs real-time risks of being repurposed for political ends.

Particles' changing masses could explain why distant galaxies appear to be rushing away.

Light-matter interfaces implementing arbitrary conditional operations on incoming photons would have several applications in quantum computation and communications. Here, the authors demonstrate conditional polarization rotation induced by a single quantum dot spin embedded in an electrically contacted micropillar, spanning up to a pi flip.

A versatile cloud-accessible single-photon-based quantum computing machine is developed, which shows a six-photon sampling rate of 4 Hz over weeks. Heralded generation of a three-photon Greenberger–Horne–Zeilinger state—a key milestone toward measurement-based quantum computing—is implemented.

The discovery of a multiply imaged, probably of type Ia, supernova in a galaxy at redshift 1.95 enables a time-delay measurement with an uncertainty of <1%. The prediction that a new image will appear in the year 2037 ± 2 allows the use of this system as a cosmological probe.

An analysis of cancer mortality data for zoo mammals highlights marked differences across mammalian orders and an influence of diet, and shows that mortality risk is largely independent of body mass and life expectancy across species.

A three-partite cluster state made of one semiconductor spin and two indistinguishable photons is generated from an InGaAs quantum dot embedded in a pillar microcavity. The three-partite entanglement rate is 0.53 MHz at the output of the device.

Experiments show that the dynamics of phase fluctuations  in a one-dimensional polariton condensate falls in the Kardar–Parisi–Zhang universality class, and theoretical analysis supports this finding revealing the key signatures of this universality class.

Long-lived polariton condensates can propagate well beyond the area of their initial excitation while still maintaining spatial coherence. This enables direct and controllable manipulation of the condensate wavefunction.

The interaction between electron and nuclear spins in quantum dots is often seen as detrimental for the use of electron spin for quantum information processing. It is now shown, however, that such interaction can be used to coherently control the polarization of tens of thousands of nuclear spins, opening the way to experiments using nuclear rather than electron spin.

The Josephson effects that arise when two quantum states are coupled through a barrier are difficult to observe in optical systems because photon–photon interactions are so weak. Researchers have now demonstrated an optical realization of two such phenomena—macroscopic self-trapping and Josephson oscillations—using polariton condensates in overlapping microcavities.

A photon-number Bell state is generated from a quantum dot by controlling the light–matter entanglement during spontaneous emission. This excitation protocol can be scaled up by using N consecutive π-pulses to deliver multimode photonic entanglement.

The hippocampus in mammalian brain varies in size across individuals. Here, Hibar and colleagues perform a genome-wide association meta-analysis to find six genetic loci with significant association to hippocampus volume.

Quantum dots are a promising host for spin-based qubits. Whereas nuclear-field fluctuations adversely affect electron-spin coherence, the smaller hyperfine interaction between holes and nuclei makes holes a promising alternative. A sensitive measurement of the hyperfine constant of the holes in different quantum-dot material systems now demonstrates how this interaction can be tuned and perhaps further reduced.