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There are many quantum systems that act as high-quality quantum harmonic oscillators, and they can be used to store quantum information using the Gottesman–Kitaev–Preskill code. Entangling gates have now been demonstrated between two of these qubits.

A loophole-free violation of Bell’s inequality with superconducting circuits shows that non-locality is a viable new resource in quantum information technology realized with superconducting circuits, promising many potential applications.

Entangled particles some distance apart can be used to show the strikingly nonlocal nature of quantum mechanics. Here the authors generate spatially separated pairs of helium atoms by colliding Bose-Einstein condensates and show that they are entangled by observing nonlocal correlations.

A violation of Bell’s inequality would prove that a classical deterministic view of the universe is incorrect; however, despite long-standing efforts, irrefutable experimental proof of such a violation has yet to be produced. Teo et al. propose a realistic scenario that may finally overcome this challenge.

Long-lived entanglement is a key resource for quantum metrology with optical clocks. Rydberg-based entangling gates within arrays of neutral atoms enable the generation of clock-transition Bell states with high fidelity and long coherence times.

This study demonstrates the experimental realization of a complete protocol for quantum key distribution using entangled trapped strontium ions with device-independent quantum security guarantees.

In-cell NMR reveals the molecular details of NDM-1 degradation, an enzyme linked to antibiotic resistance, and sheds light on protein quality control in the periplasm of live bacteria at an atomic level.

Qubit-cavity entanglement can be used for quantum information processing and for investigating the quantum-to-classical transition with high control. Here, the authors characterize the entanglement between an artificial atom and a cat state and its susceptibility to decoherence through Bell test witnesses.

A Bell experiment that is ‘loophole’ free—leaving no room for explanations based on experimental imperfections—reveals a statistically significant conflict with local realism

A study demonstrates a public generator of random numbers based on device-independent techniques, with the randomness being fully auditable and traceable.

Bell inequalities are a quantitative measure that can distinguish classically determined correlations from stronger quantum correlations, and their measurement provides strong experimental evidence that quantum mechanics provides a complete description. The violation of a Bell inequality is now demonstrated in a solid-state system; the experiment provides further strong evidence that a macroscopic electrical circuit is really a quantum system.

Erwin Schrödinger introduced in 1935 the concept of ‘steering’, which generalizes the famed Einstein–Podolsky–Rosen paradox. Steering sits in between quantum entanglement and non-locality — that is, entanglement is necessary for steering, but steering can be achieved, as has now been demonstrated experimentally, with states that cannot violate a Bell inequality (and therefore non-locality).

While Bell inequalities have been violated several times—mostly in photonic systems—their violations within particle physics experiments are less explored. Here, the BESIII Collaboration showcases Bell-violating nonlocal correlations between entangled hyperon pairs.

Bell’s theorem experiments, which test the completeness of quantum mechanics, have a number of loopholes. However, one type—detection loopholes—becomes smaller when the measurement has more possible outcomes. Bell’s inequality is now violated in tests with as many as 11 different results.

Web summaryHarnessing the entanglement of different ionic species could bring new flexibility in quantum computing, and now two groups independently demonstrate entanglement between different atomic species; Ballance et al. achieve entanglement between different atomic isotopes, whereas the related paper by Tan et al. shows entanglement between different elements, together demonstrating a first step towards mixed-species quantum logic.

Drugs that rescue function of episodic ataxia 1 (EA1) mutant potassium channels are lacking. Here, Manville et al identify and describe the molecular basis for Native American botanical ataxia remedies that directly rescue EA1 mutant channels.

A 142-qubit processor can be realized by connecting two smaller quantum processors using classical communications and circuit cutting.

A four-qubit processor of three phosphorus nuclear spins and an electron spin in silicon enables the implementation of a three-qubit Grover’s search algorithm with 95% fidelity. The implementation is based on an advanced multi-qubit gate with single-qubit gate fidelities above 99.9% and two-qubit gate fidelities above 99%.

Future quantum networks will require entangled photons operating in the telecommunications band, so they can integrate with existing architectures. Ward et al.present a quantum-dot-entangled-photon-pair source in this region and a method to measure the fidelity of a time-evolving Bell state.

Quantum key distribution (QKD) holds promise for unconditionally secure communication, but due to fibre losses distances are so far restricted to intracity. Here, the authors present an all optical QKD protocol that can connect distant cities without the need of quantum repeaters or quantum error correction.

Prion-like proteins in Escherichia coli trigger an abortive infection mechanism in response to phage infection—a process similar to amyloid-mediated immune signalling in fungi and animals.

Inhibitors of the protein kinase Wee1 are promising drugs for cancer therapy. Here, the authors show that these drugs activate the integrated stress response via GCN2, synergising with mRNA translation defects. They suggest strategies such as PROTACs or ISR inhibitors to improve WEE1 mediated toxicity.

Recent advancements have enabled quantum control and measurement of mechanical resonators. Here the authors demonstrate quantum entanglement between two mechanical resonators on separate substrates by sharing one and two quanta of energy, followed by quantum measurement of these entangled states.

A deterministic violation of the Bell inequality is reported between two superconducting circuits, providing a necessary test for establishing strong enough quantum entanglement to achieve secure quantum communications.

Beck et al. develop a model where striosomes create a flexible “decision-space” that adapts to environmental context and internal state. It explains how we make choices and why decision-making varies between people, and in neuropsychiatric disorders.

Practical implementations of quantum communication need to securely deliver information over long distances without line-of-sight. Towards this goal, Cuevas et al.use an actively stabilized interferometer to close the geometry loophole for a Bell inequality violation over 1 km of optical fibre.

Entangled local states can be made capable of violating Bell inequalities via nonlocality activation. Typical theoretical approaches require processing many copies of the original state and performing joint measurements on the ensemble. Here, instead, the authors experimentally demonstrate how to do so using a single copy of the state, broadcasting it to two spatially separated parties within a three-node network.

Quantum steering is a form of quantum non-locality that can be verified for arbitrarily low detection efficiencies and high losses at the price of requiring complete trust in one of the parties. Here, Kocsis et al. present measurement-device-independent steering protocols that remove this need for trust.

Untrustworthy sources or detectors mean that quantum entanglement cannot always be ensured, but quantum steering inequalities can verify its presence. Using a highly efficient system, Smithet al. are able to close the detection loophole and clearly demonstrate steering between two parties.

Polyamides (PAs) or nylons are types of plastics with wide applications, but due to their accumulation in the environment, strategies for their deconstruction are of interest. Here, the authors screen 40 potential nylon-hydrolyzing enzymes (nylonases) using a mass spectrometry-based approach and identify a thermostabilized N-terminal nucleophile hydrolase as the most promising for further development, as well as crucial targets for progressing PA6 enzymatic depolymerization.

Spontaneous parametric down-conversion, the standard technique for generating entangled photons, is limited by low pair extraction efficiencies at near-unity fidelity. The authors show quantum dots in nanowires efficiently emit an oscillating state with near-unity entanglement fidelity and propose a time-resolved quantum key distribution protocol.

A programmable quantum processor based on encoded logical qubits operating with up to 280 physical qubits is described, in which improvement of algorithmic performance using a variety of error-correction codes is enabled.

Researchers demonstrate a reconfigurable integrated quantum photonic circuit. The device comprises a two-qubit entangling gate, several Hadamard-like gates and eight variable phase shifters. The set-up is used to generate entangled states, violate a Bell-type inequality with a continuum of partially entangled states and demonstrate the generation of arbitrary one-qubit mixed states.

The authors find subtype-specific influenza cross-reactivity patterns, including rapid declines for A(H3N2) within 6 years, sustained responses for A(H1N1)pdm09 and increased cross-reactive responses in humans after repeated A(H3N2) exposure.