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Real-time adaptive control of a qubit has been demonstrated but limited to single-axis Hamiltonian estimation. Here the authors implement two-axis control of a singlet-triplet spin qubit with two fluctuating Hamiltonian parameters, resulting in improved quality of coherent oscillations.

By implanting ¹¹⁷Sn, a fibre-packaged nanophotonic diamond waveguide with optically addressable hyperfine transitions separated by 452 MHz is demonstrated. This enables the formation of a spin-gated optical switch and achieving a waveguide-to-fibre extraction efficiency of 57%.

A family of multi-qubit Rydberg quantum gates is developed and used to generate Schrödinger cat states in an optical clock, allowing improvement in frequency measurement precision by taking advantage of entanglement.

Einstein challenged physics to describe “the real factual situation”. But an understanding of the very concepts that he criticized a century ago may provide the best clues yet about reality ‘out there’.

The triangle causal structure represents a departure from the usual Bell scenario, as it should allow to violate classical predictions without the need for external inputs setting the measurement bases. Here the authors realise this scenario using a photonic setup with three independent photon sources.

A three-partite cluster state made of one semiconductor spin and two indistinguishable photons is generated from an InGaAs quantum dot embedded in a pillar microcavity. The three-partite entanglement rate is 0.53 MHz at the output of the device.

It is hoped that simulations of molecules and materials will provide a near-term application of quantum computers. A study of the performance of error mitigation highlights the obstacles to scaling up these calculations to practically useful sizes.

Many-body quantum systems that escape thermalization are promising candidates for quantum information applications. A weak-ergodicity-breaking mechanism—quantum scarring—has now been observed with superconducting qubits in unconstrained models.

Experiments demonstrate the powerful capabilities of ultracold molecules to study dynamics in the context of quantum magnetism, and create new possibilities for studying quantum physics with ultracold molecules more broadly.

Multipartite entangled states are a fundamental resource for quantum information processing tasks; it is thus important to verify their presence. Here the authors present and demonstrate a protocol that allows any party in a network to verify if an untrusted source is distributing multipartite entangled states.

Light could be used to carry quantum information in networks, but this requires methods to prepare and control individual photons. A superconducting circuit can controllably emit photons in either direction along a microwave waveguide.

The realization of two-qubit entangling gates with 99.5% fidelity on up to 60 rubidium atoms in parallel is reported, surpassing the surface-code threshold for error correction and laying the groundwork for neutral-atom quantum computers.

Quantum physics aims another blow at common sense: a simple quantum computer gives the right answer, even when it is not run. (Traditionalists be comforted: the computer must be turned on.)

Monkey King is first in a line of Chinese space missions focused on scientific discovery.

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.

The wave-particle duality postulate is well verified and holds that 'atomic' particles have wave as well as particle properties. But, in terms of increasing mass, how far does this principle of quantum theory apply? Experiments with the fullerene C₆₀extend evidence for wave-particle behaviour by an order of magnitude towards -- but still far short of -- the macroscopic domain.

New types of nonlocal correlations can arise in quantum networks, but experiments have not been done for more than two independent sources. Here, the authors violate a chained n-locality inequality in a network with five nodes and four independent sources, relying only on single-qubit measurements.

A proposed network of atomic clocks—using non-local entangled states—could achieve unprecedented stability and accuracy in time-keeping, as well as being secure against internal or external attack.

Entanglement in many-body systems is notoriously hard to quantify, but in certain situations relevant to atomic and condensed-matter experiments an entanglement witness, the quantum Fisher information, becomes measurable by means of the dynamic susceptibility.

Creating entangled photon states becomes technologically ever more difficult as the number of particles increases, and the current record stands at six entangled photons. However, using both their polarization and momentum degrees of freedom, up to ten-qubit states can be encoded in ‘only’ five photons, as has now been demonstrated.

Quantum computers, which harness the superposition and entanglement of physical states, hold great promise for the future. Here, the demonstration of a two-qubit superconducting processor and the implementation of quantum algorithms, represents an important step in quantum computing.

Manipulating the electrons trapped in quantum-dot pairs is one possible route to quantum computation. Translating this idea to three quantum dots would enable a whole host of extended functionality. Researchers now generate and manipulate coherent superpositions of quantum states using the spins across three electrical-gate-defined dots.

The observation of controlled adiabatic evolution from paramagnetic into ferromagnetic order in a system made of two trapped ions represents an initial step into the emerging field of quantum simulation.

Quantum measurements are subject to an uncertainty that is usually distributed equally between pairs of complementary properties (such as position and momentum). However, a technique known as 'squeezing' can be used to reduce the uncertainty of one desired property at the expense of increasing that of the other. Squeezing may have a critical role in high precision applications such as atomic clocks and optical communications. This paper demonstrates the ultimate squeezing limit for the polarization of a composite optical system.

So-called one-way schemes have emerged as a powerful model to describe and implement quantum computation. This article reviews recent progress, highlights connections to other areas of physics and discusses future directions.

Optical entanglement — a key requirement for many quantum communication protocols — is typically formed between two distinct beams, requiring repeated combination of complex resources, which becomes increasingly difficult as the number of entangled information channels increases. Here entanglement between two spatial modes within one beam is demonstrated.

Quantum communication networks are expected to exceed the performance of communications systems based on classical physics in terms of security and communication efficiency and contribute towards the formation of quantum internet. Here, the authors present a model of complex quantum communication networks based on quantum Ising spins where entangled clusters serve as efficient communication channels.

In 2000, Asher Peres put forward the paradoxical idea that entanglement could be produced after the entangled particles have been measured, even if they no longer exist. Researchers now experimentally demonstrate this idea using four photons.

Physicists have spent a century puzzling over the paradoxes of quantum theory. Now a few of them are trying to reinvent it.