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In superconducting circuits, the nonlinearity of Josephson junctions mediates photon interactions, but they are typically dominated by two-photon processes. Here the authors observe multi-photon interactions in a superconducting circuit with Cooper-pair pairing, revealing a new regime of microwave quantum optics.

Spin-entangled electron pairs are one possible resource for future solid-state quantum information processing systems. Here, the authors directly prove spin entanglement between two electrons that had previously been a Cooper pair in a superconducting lead but were split using two quantum dots.

By coupling two quantum dots via a superconductor-semiconductor hybrid region in a 2D electron gas, the authors achieve efficient splitting of Cooper pairs. Further, by applying a magnetic field perpendicular to the spin-orbit field, they can induce and measure large triplet correlations in the Cooper pair splitting process.

Disorder leads to localization of electrons at low temperatures, changing metals to insulators. In a superconductor the electrons are paired up, and scanning tunnelling microscopy shows that the pairs localize together rather than breaking up and forming localized single electrons in the insulating state.

Controllable detection of singlet and triplet Cooper pair splitting via crossed Andreev reflection is demonstrated in spin-polarized quantum dots on a superconducting nanowire platform with strong spin–orbit coupling.

Whether and how the Dirac electrons can be driven into superconducting state remains unclear. Here, Duet al. present systematic study to demonstrate the Dirac electrons condensing into Cooper pairs on the surface of a possible topological superconductor Sr_xBi₂Se₃.

One minute parity lifetimes are reported in a superconducting transistor made of niobium titanite nitride coupled to aluminium contacts even in the presence of small magnetic fields, enabling the braiding of Majorana bound states.

By pushing scanning tunnelling spectroscopy down to millikelvin temperatures, it is now possible to image a heavy fermion superconductor and measure the superconducting gap symmetry, with gap nodes in unexpected momentum-space locations.

One of the most counterintuitive fundamental properties of quantum mechanics is non-locality, which manifests itself as correlations between spatially separated parts of a quantum system. Although experimental tests of non-locality (Bell inequalities) have been successfully conducted with pairwise entangled photons, similar demonstrations using electrons have so far not been possible. The realization of a Y-shaped tunable Cooper pair splitter, to split entangled electrons on demand, brings this one step closer.

Although quantum phase transitions are attracting increasing attention as the conceptual link between conventional and exotic states of quantum matter—having been implicated, for example, in the properties of high-temperature superconductors—there are few model systems in which they can be studied and understood. Now it is revealed that placing simple elemental chromium under pressure suppresses its normal magnetic state and gives direct experimental access to the underlying quantum phase transition responsible for these changes.

Scanned Josephson tunnelling microscopy is used to image Cooper pair tunnelling from a superconducting microscope tip to the quantum condensate of Bi₂Sr₂CaCu₂O_8+x, thus revealing the spatially modulated density of Cooper pairs predicted from several theories of the cuprate pseudogap phase.

Owing to electron localization, two-dimensional materials are not expected to be metallic at low temperatures, but a field-induced quantum metal phase emerges in NbSe₂, whose behaviour is consistent with the Bose-metal model.

A measurement strategy is described that is able to read out the parity of minimal two-site Kitaev chains in real time, by coupling two Majoranas and resolving their quantum capacitance.

Werner et al. present the results of the 201 Trial, a 12-week randomized, double-blind placebo-controlled phase 2a study of risvodetinib, in patients with early untreated Parkinson’s disease. Risvodetinib was found to be safe and well tolerated.

The standard model describes many aspects of particle physics but mechanisms such as the binding of quarks into hadrons, still remain a mystery. The authors theoretically outline an analogy with the Cooper pairs of a superinsulator to demonstrate that the mechanisms behind the infinite resistance of a superinsulator are analogous to that which confine quarks into hadrons.

Terahertz microspectroscopic imaging at subgap millielectronvolt energies of a two-dimensional superfluid plasmon in few-layer Bi₂Sr₂CaCu₂O_8+x is demonstrated, allowing the spatial resolution of its deeply subdiffractive terahertz electrodynamics.

Quarks in the interior of hadrons make up most of ordinary matter, yet their observation is not possible, and their properties can only be probed indirectly. Adopting an analogy between physics of superinsulators and high energy physics, the authors present direct observations of the interior of electric mesons made of Cooper pairs by standard transport measurements.

Superconducting spintronics has the potential to enhance device functionality by realising spin polarised supercurrents with greater coherence and reduced dissipation. Here, using ferromagnetic resonance, the authors investigate the temperature dependence of the Gilbert damping for the Fe layer of Nb/Fe/Nb and Nb/Cr/Fe/Cr/Nb stacks and the impact superconducting spin triplets have on the spin pumping behaviour.

In high-temperature superconductors, a very low density of states, the pseudogap, exists even above the critical temperature. Here, the authors show that this is also the case for a conventional superconductor, titanium nitride thin films, and that this pseudogap is induced by superconducting fluctuations.

Johnson et al. link ARIA, a complication of anti-amyloid therapy, to clonal expansion of cytotoxic CD8 + T cells with glycolytic reprogramming and vascular trafficking potential, with implications for biomarker development and risk mitigation.

Transition of superfluid to insulator is observed in the layer-imbalanced regime of bilayer magnetoexcitons.

The authors present experimental evidence of three-dimensional superinsulation in a nanopatterned slab of NbTiN. In the electric Meissner state, they find polar nematic order arising from ferroelectric alignment of short electric strings excited by external electromagnetic fields.

Antigen presentation in skull bone marrow by hematopoietic stem and progenitor cells induces myelopoiesis and generates CD4⁺ regulatory T cells in a mouse model of ependymoma, promoting immune tolerance. Treatment with anti-GM-CSF antibody has antitumor effects that are augmented by immunotherapy.

This Review highlights chip-scale superconducting coherent photon source technologies and their rich potential as an important integrated quantum hardware to advance quantum information processing and communication networks.

The authors observe shot noise orders of magnitude greater than expected in superconductor/insulator/ferromagnet (V/MgO/Fe) junctions. They argue that the origin involves orbital-symmetry-controlled superconducting proximity effect and spin-triplet superconductivity in the Fe.

A hidden quality-control system to filter out defective sperm during development is exploited by selfish genes to eliminate competing chromosomes.

Chiral superconductors are very rare topological materials. Here, the authors report spontaneous magnetic fields inside the superconducting state and low temperature linear behavior in the superfluid density in LaPt₃P, suggesting a chiral d-wave singlet superconducting state.

Sabatino and colleagues examine expanded CD8⁺ T cell clonotypes from a small cohort of multiple sclerosis patients. They identified several cognate peptide epitopes that derive from Epstein–Barr virus, suggesting EBV reactivation may drive pathogenesis in these patients.

The authors study a disordered β-Ta film, finding that quasiparticle recombination is governed by the phonon scattering time, which is faster than conventional recombination in ordered superconductors. The authors interpret the results in terms of quasiparticle localization, which helps to understand the quasiparticle relaxation in disordered superconducting circuits.

Natural Killer cells are key mediators of anti-tumour immunosurveillance and anti-viral immunity. Here, the authors map regulatory genetic variation in primary Natural Killer cells, providing new insights into their role in human health and disease.

A major mystery in cuprate superconductors is how Cooper pairs form and condense. Here, the authors use RIXS and STM techniques to reveal that a charge-ordered insulating phase and enhanced bond-buckling phonons play important roles in this process.

The authors study epitaxial thin films of the pyrochlore-sublattice compound LiTi2O4 by RIXS and ARPES. They observe cooperation between strong electron correlations and strong electron-phonon coupling, giving rise to a mobile polaronic ground state in which charge motion and lattice distortions are coupled.

Conventional superconductors were thought to be spin inert, but long-lived, spin-polarized excitations, or quasiparticles, have recently been observed. Here, the authors demonstrate quasiparticle spin resonance in the mesoscopic superconductor aluminium and estimate the spin coherence time.

The ALICE Collaboration provides details on the microscopic mechanism that ends up creating antideuteron in high-energy proton–proton collisions at the Large Hadron Collider.

Exploring the photoionization process leads to better understanding of the fundamental interactions between light and matter. Here the authors show the non-dipole contribution in the form of asymmetric photoelectron angular distribution from the ionization of argon atoms and ions.

NbN/AlN/NbN qubits prepared by atomic layer deposition allow for precise control of the tunnelling barrier and stable operation beyond the temperature limit of aluminium-based devices.

Superconducting circuits are promising for quantum computing, but quasiparticle tunnelling across Josephson junctions introduces qubit decoherence. Ristè et al. convert a transmon qubit into its own real-time quasiparticle tunnelling detector and accurately measure induced decoherence in the millisecond range.