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Fierce rivals have joined forces in the race to teleport information to and from space.

Low-loss superconducting aluminium cables and on-chip impedance transformers can be used to link qubit modules and create superconducting quantum computing networks with high-fidelity intermodule state transfer.

An 11-qubit atom processor comprising two precision-placed nuclear spin registers of phosphorus in silicon is shown to achieve state-of-the-art Bell-state fidelities of up to 99.5%.

Parity-breaking antisymmetric spin exchange interaction is reported in clusters of five qubits within superconducting circuits. This allows the creation of chiral spin dynamics, with potential for future quantum simulations of chiral molecules.

Distant quasars would decide whether quantum entanglement is an illusion.

According to Bell's theorem, any theory that is based on the joint assumption of realism and locality is at variance with certain quantum predictions. Here, theory and experiment agree that a class of such non-local realistic theories is incompatible with experimentally observable quantum correlations, suggesting that giving up the concept of locality is not sufficient to be consistent with quantum experiments, unless certain intuitive features of realism are abandoned.

Poll reveals diverse views about foundational questions in physics.

By suppressing questions they considered too ‘philosophical’, post-war physicists created an unquestioning orthodoxy that influences science to this day.

Perfect State Transfer is known to time-optimally connect distant nodes in a network. Here, the authors implement it on a chain of superconducting qubits and demonstrate that it also serves as a powerful tool for generating multi-qubit entanglement.

Fermionic systems in a pure state are subject to restrictions on the natural orbital occupation, known as the generalized Pauli constraints. The authors probe the violation of such constraints in 3-to-7 qubit systems, experimentally demonstrating that the one-fermion reduced density matrix encodes the openness of a fermionic quantum system.

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.

Future quantum computers will employ error correction to protect quantum data from decoherence and faulty hardware. Here, using a quantum processor with five superconducting qubits, the authors demonstrate how to protect one logical qubit from bitflip errors using multi-qubit, stabilizer measurements.

A method is described for the generation of large-scale entanglement that can be used for quantum-enhanced sensing even when systems are limited to short-range interactions in experiments with up to 51 trapped ions.

High-fidelity deterministic quantum state transfer and multi-qubit entanglement are demonstrated in a quantum network comprising two superconducting quantum nodes one metre apart, with each node including three interconnected qubits.

Efficient protocols for comparing quantum states generated on different quantum computing platforms are becoming increasingly important. Zhu et al. demonstrate cross-platform verification using randomized measurements that allow for scaling to larger systems as compared to full quantum state tomography.

Exploring correlations in strongly entangled quantum materials is of interest. Here the authors generate a tunable spin-, trajectory-, and energy-entangled neutron beam using a neutron spin-echo interferometer and show violations of Clauser-Horne-Shimony-Holt and Mermin contextuality inequalities with micron-scale trajectory separation.

The emerging field of quantum information science is harnessing nature's strangest habits — and providing an academic haven for young physicists. Eric Hand reports.

Networks have been widely explored in the context of classical statistical mechanics. But when quantum effects are added, qualitatively different behaviours emerge, even for the simplest cases.

The ability to assemble weakly-interacting subsystems is a prerequisite for implementing quantum-information processing. In recent years, molecular nanomagnets have been proposed as suitable candidates for qubit encoding and manipulation, with antiferromagnetic Cr₇Ni rings of particular interest. It has now been shown that such rings can be chemically linked to each other and the coupling between their spins tuned through the choice of chemical linker.

A programmable neutral-atom quantum computer based on a two-dimensional array of qubits led to the creation of 2–6-qubit Greenberger–Horne–Zeilinger states and showed the ability to execute quantum phase estimation and optimization algorithms.

Universal quantum logic operations with fidelity exceeding 99%, approaching the threshold of fault tolerance, are realized in a scalable silicon device comprising an electron and two phosphorus nuclei, and a fidelity of 92.5% is obtained for a three-qubit entangled state.

Silicon-based spin qubits are promising candidates for a scalable quantum computer. Here the authors demonstrate the violation of Bell’s inequality in gate-defined quantum dots in silicon, marking a significant advancement that showcases the maturity of this platform.

Vienna demonstration shows that the technology can boost data capacity of laser beams over long distances.

The orbital angular momentum of light is a promising degree of freedom for long-distance information transportation. To create high-dimensional entanglement for pairs of photons, Fickler et al.use an optical mode sorter in reverse to transfer entanglement between the path into the orbital angular momentum.

Photons are essential for quantum information processing, but to date only two-qubit single-photon operations have been realized. Here the authors demonstrate experimentally a three-qubit single-photon linear deterministic quantum gate by exploiting polarization along with spatial-parity symmetry.

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.

Quantum information processing normally uses either discrete- or continuous-variable encoding. Here, the authors bridge the two approaches, showing how to entangle Schrodinger’s cats states by conversion between Bell states in the Fock and cat bases and by a simple Fock-state-like gate operation.

A large nuclear spin has been successfully placed in a Schrödinger cat state, a superposition of its two most widely separated spin coherent states. This can be used as an error-correctable qubit.

A quantum error correction scheme is demonstrated in a system of superconducting qubits, and repeated quantum non-demolition measurements are used to track errors and reduce the failure rate; increasing the system size from five to nine qubits improves the failure rate further.

Micrometre-scale superconducting circuits are at present explored as the building blocks for scalable quantum information processors. In a system where two such qubits are coupled to a resonant cavity, tripartite interactions and controlled coherent dynamics have now been demonstrated. This platform should allow for a fuller exploration of multipartite quantum states and their deterministic preparation.

A digitized approach to adiabatic quantum computing, combining the generality of the adiabatic algorithm with the universality of the digital method, is implemented using a superconducting circuit to find the ground states of arbitrary Hamiltonians.

A universal set of logic gates in a superconducting quantum circuit is shown to have gate fidelities at the threshold for fault-tolerant quantum computing by the surface code approach, in which the quantum bits are distributed in an array of planar topology and have only nearest-neighbour couplings.

Quantum discord is the total non-classical correlation between two systems. This includes, but is not limited to, entanglement. Photonic experiments now demonstrate that separable states with non-zero quantum discord are a useful resource for quantum information processing and can even outperform entangled states.

Quantum teleportation — the transmission and reconstruction over arbitrary distances of the state of a quantum system — is demonstrated experimentally. During teleportation, an initial photon which carries the polarization that is to be transferred and one of a pair of entangled photons are subjected to a measurement such that the second photon of the entangled pair acquires the polarization of the initial photon. This latter photon can be arbitrarily far away from the initial one. Quantum teleportation will be a critical ingredient for quantum computation networks.

Quantum simulations, where one quantum system is used to emulate another, are starting to become experimentally feasible. Here, four-photon states are used to simulate spin tetramers, which are important in the description of certain solid-state systems. Emerging frustration within the tetramer is observed, as well as evolution of the ground state from a localized to a resonating-valence-bond state.

A proof-of-principle study reports a complete photonic quantum computer architecture that can, once appropriate component performance is achieved, deliver a universal and fault-tolerant quantum computer.

By emulating a 2D hard-core Bose–Hubbard lattice using a controllable 4 × 4 array of superconducting qubits, volume-law entanglement scaling as well as area-law scaling at different locations in the energy spectrum are observed.

Entanglement of two nanophotonic quantum network nodes is demonstrated through 40  km spools of low-loss fibre and a 35-km long fibre loop deployed in the Boston area urban environment.