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The no-signaling principle constrains which multipartite correlations are allowed, but network scenarios considered so far were limited to specific cases. Here, the authors apply inflation technique to the no-input/binary-output triangle network, and show that it admits non-trilocal distributions.

Experimentally verifying that quantum states are indeed entangled is not always straightforward. With the recently proposed device-independent entanglement witnesses, genuine multiparticle entanglement of six ions has now been demonstrated.

In 1997, it was demonstrated that quantum states can be teleported from one location to a distant one. The discovery had huge consequences for the development of quantum communication and computing.

Harnessing entanglement between light and material systems is of interest for future quantum information technologies. Here, entanglement is demonstrated between a photon at the telecommunication wavelength (1,338 nm) and a single collective atomic excitation stored in a crystal. These resources pave the way for building multiplexed quantum repeaters for long-distance quantum networks.

Researchers observe heralded entanglement between two neodymium ensembles doped in Nd³⁺:Y₂SiO₅ crystals separated by 1.3 cm. The high level of interference indicates that the stored entanglement does not significantly decohere over a period of 33 ns. They demonstrate that rare-earth-ion ensembles have the potential to form compact, stable and coherent quantum network nodes.

Quantum mechanics enables distant events to be more strongly correlated than is possible classically. The proposal for a new family of experimental tests, and the implementation of one of them, provides further insight into the nature of such non-local correlations.

The presence of entanglement in macroscopic systems is notoriously difficult to observe. Here, the authors develop a witness which allow them to demonstrate entanglement between millions of atoms in a solid-state quantum memory prepared by the heralded absorption of a single photon.

Quantum communication applications require memories capable of storing multiple qubits. To implement scalable architectures for this purpose, Usmani and coworkers turn to a rare-earth doped silicate, in which they demonstrate coherent and reversible mapping of 64 optical modes at the single photon level.

Experiments have almost ruled out a classical explanation for entanglement, but it is possible that one event could influence a second if the influence occurs faster than the speed of light. The authors put experimental bounds on the speed of such hypothetical influences.

Quantum teleportation of the state of a qubit encoded in the polarization state is demonstrated from a telecom-wavelength photon to a solid-state quantum memory via 24.8 km of optical fibre. It is the longest distance ever reached in a teleportation experiment involving a quantum memory.

A discrete-variable quantum key distribution system that is capable of distributing a provably-secure cryptographic key over 307 kilometres is demonstrated at a telecom wavelength.

To realize scalable quantum information networks, it will be important to develop techniques for storage and retrieval of light at the single photon level. Quantum interfaces between light and matter have been demonstrated, but mainly with atomic gases that involve sophisticated schemes to trap the atoms. This paper demonstrates a potentially more practical approach; coherent and reversible mapping of a light field with less than one photon per pulse onto an ensemble of ∼10⁷ atoms naturally trapped in a solid state medium. The state of the light is mapped onto collective atomic excitations on an optical transition and stored for a pre-programmed time up of to one microsecond before being retrieved again.

A direct quantum equivalent of an electronic NOT gate is impossible. But the best possible approximation to the universal NOT transformation has now been demonstrated using photons.

Physics is formulated in terms of timeless, axiomatic mathematics. A formulation on the basis of intuitionist mathematics, built on time-evolving processes, would offer a perspective that is closer to our experience of physical reality.

Full network nonlocality, which certifies nonclassical behaviour in all sources of quantum networks, has so far only been demonstrated in the simplest scenarios. Here, the authors reach a complete experimental demonstration in a complex network involving three-qubit joint measurements.

Although they offer significant promise, practical implementations of quantum key distribution are often not as rigorous as theory predicts. This study demonstrates how two instances of such discrepancies can be resolved by taking advantage of an enotropic formulation of the uncertainty principle.

A Bell-like experiment that discriminates between real-number and complex-number multipartite quantum systems could disprove real quantum theory.

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.

Long coherence times in a subset of states that allows for transitions in both microwave and optical range have been reported using an isotopically purified ¹⁷¹Yb³⁺:Y₂SiO₅ crystal, rendering the system suitable for quantum information applications.