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Guaranteed entanglement sharing over long distances can be verified by violating a Bell inequality. That's a tricky enough proposition in itself, but what if more than two parties are involved?

Light is an excellent tool for making precise measurements of objects, but can sometimes alter or damage a sensitive sample. Researchers have now shown that entanglement and quantum-correlated light can be used to help alleviate this problem.

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.

Polarization is a convenient way to encode quantum information for cryptography, remote transfer and optical quantum computing, but sharing entanglement is problematic over a noisy link. Hiding in an isolated corner of the state space can make a big difference.

Quantum systems are uncertain by nature. By 'squeezing' this uncertainty, physicists can make better measurements of quantities such as distance. But overdoing it makes things burst out all over the place.

Unconditional entanglement-enhanced photonic interferometry is implemented by using a state-of-the-art photon source and detectors. Sampling a birefringent phase shift, precision beyond the shot-noise limit is demonstrated without data correction.

Quantum devices should allow simulating stochastic processes using less memory than classical counterparts, but only if quantum coherence is maintained through multiple steps. Here, the authors demonstrate a coherence-preserving three-step stochastic simulation using photons.

Measurements of an unknown optical phase have not yet been performed with the ultimate precision, i.e. saturating the Heisenberg limit. Here, Daryanoosh et al. demonstrate this with a precision within 4% of the Heisenberg limit by combining photonic entanglement and multiple passes.

Quantum channel correction could provide a remedy to unavoidable losses in long-distance quantum communication, but the break-even point has escaped demonstration so far. Here, the authors fill this gap using distillation by heralded amplification, followed by teleportation of entanglement.

For a scenario of two separated but entangled observers, inequalities are derived from three fundamental assumptions. An experiment shows that these inequalities can be violated if quantum evolution is controllable on the scale of an observer.

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.

A manufacturable platform for quantum computing with photons is introduced and a set of monolithically integrated silicon-photonics-based modules is benchmarked, demonstrating dual-rail photonic qubits with performance close to thresholds required for operation.

A general approach to simplifying quantum logic circuits—the ‘programs’ of quantum computers—is described and demonstrated on a platform based on photonic qubits.