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Reducing rotational dephasing is a major challenge in ultracold molecules. Here, the authors demonstrate coherent control of three rotational states in ultracold molecules trapped in magic-wavelength optical tweezers, opening prospects towards quantum applications with higher-dimensional systems.

Two-qubit operations exceeding 99% fidelity have been demonstrated by silicon devices made with standard semiconductor tooling in a 300-mm foundry environment.

Impurity spins in silicon can be controlled with microwaves and then read-out electrically, offering a promising platform for quantum information applications. Here, the authors show that terahertz pulses can be used to address the orbital degree of freedom as well, which can also be detected electrically.

Conveyor-mode spin shuttling using a two-tone travelling-wave potential demonstrates an order of magnitude better spin coherence than bucket-brigade shuttling, achieving spin shuttling over 10 μm in under 200 ns with 99.5% fidelity in an isotopically purified Si/SiGe heterostructure.

Carbon nanotubes are promising hosts for spin qubits, however existing demonstrations show limited coherence times. Here the authors report quantum states in a carbon-nanotube-based circuit driven solely by cavity photons and exhibiting a coherence time of about 1.3 μs.

The presence of various noises in the qubit environment is a major limitation on qubit coherence time. Here, the authors demonstrate the use a closed-loop feedback to stabilize frequency noise in a flux-tunable superconducting qubit and suggest this as a scalable approach applicable to other types of noise.

Gatemons, or gate-tunable transmons, are superconducting qubits based on hybrid Josephson junctions, which typically use extended quantum conductors as weak links. Here the authors report a gatemon made with a carbon-nanotube-based junction, showing improved coherence time compared to graphene-based devices.

Quantum dot spin qubits in Si can be controlled using micromagnet-based electric-dipole spin resonance, but experiments have been limited to small 1D arrays. Here the authors address qubit control in 2D Si arrays, demonstrating low-frequency control of qubits in a 2 x 2 array using hopping gates.

Researchers demonstrate fast, single-qubit gates using a sequence of 13 ps pulses. Two vertically stacked InAs/GaAs quantum dots were coupled through coherent tunnelling and charged with controlled numbers of holes. The interaction between hole spins was investigated by Ramsey fringe experiments, showing a tunable interaction range of tens of gigahertz.

By engineering an exceptionally controlled environment using rotationally magic optical tweezers, long-lived entanglement between pairs of molecules using detectable hertz-scale interactions can be achieved.

Superconducting circuits are promising for quantum computing, but quasiparticle tunnelling across Josephson junctions introduces qubit decoherence. Ristè et al. convert a transmon qubit into its own real-time quasiparticle tunnelling detector and accurately measure induced decoherence in the millisecond range.

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.

Noise is a fundamental obstacle to the stability of atomic optical clocks. An experiment now realizes the design of a spin-squeezed clock that improves interrogation times and enables direct comparisons of performance between different clocks.

The authors fabricate a fluxonium circuit using a granular aluminium nanoconstriction to replace the conventional superconductor–insulator–superconductor tunnel junction. Their characterization suggests that this approach will be a useful element in the superconducting qubit toolkit.

Using a cryogenic 300-mm wafer prober, a new approach for the testing of hundreds of industry-manufactured spin qubit devices at 1.6 K provides high-volume data on performance, allowing optimization of the complementary metal–oxide–semiconductor (CMOS)-compatible fabrication process.

Superconducting qubits are measured using microwaves, posing constraints on its size and thermal budgets. The electro-optic transceiver presented here can be used to perform optical readout without affecting qubit performance.

A hybrid analogue–digital quantum simulator is used to demonstrate beyond-classical performance in benchmarking experiments and to study thermalization phenomena in an XY quantum magnet, including the breakdown of Kibble–Zurek scaling predictions and signatures of the Kosterlitz–Thouless phase transition.

An array of ⁸⁷Rb atoms with inter-atomic distances of 1.5 μm is prepared by holographic optical tweezers. When a pair of nearby ⁸⁷Rb atoms is optically excited to a Rydberg state, the energy exchange between the atoms is observed on a timescale of nanoseconds.

Optical clocks with a record low zero-dead-time instability of 6 × 10^–17 at 1 second are demonstrated in two cold-ytterbium systems. The two systems are interrogated by a shared optical local oscillator to nearly eliminate the Dick effect.

Quantum gates in 2D ion crystals are more challenging than in 1D. Here, the authors use their 2D ion trap platform and acousto-optical deflectors to demonstrate a 2-qubit gate that can stand the ion micromotion in such configuration.

A spin-based quantum processor in silicon achieves single-qubit and two-qubit gate fidelities above 99.5% using gate-set tomography, exceeding the theoretical threshold required for fault-tolerant quantum computing.

A scalable silicon quantum processor unit cell made of two qubits confined to quantum dots operates at about 1.5 K, achieving 98.6% single-qubit gate fidelities and a 2 μs coherence time.

Errors in a quantum computer that are correlated between different qubits pose a considerable challenge for correction schemes. Measurements of noise in silicon spin qubits show that electric field fluctuations can create strongly correlated errors.

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.

When performing interferometry-based magnetometry, there is generally a trade-off between sensitivity and range. Here, instead, the authors demonstrate a geometric-phase-based protocol which allows a 400-fold enhancement in static magnetic field range with a single NV-centre without reducing sensitivity.

High-fidelity control and readout of a superconducting qubit is performed with a low-noise optical fibre link that delivers microwave signals directly to the millikelvin quantum computing environment.

Generation of mesoscopic quantum superpositions requires both reliable coherent control and isolation from the environment. Here, the authors succeed in creating a variety of cat states of a single trapped atom, mapping spin superpositions into spatial superpositions using ultrafast laser pulses.

Long-range coherent spin-qubit transfer between semiconductor quantum dots requires understanding and control over associated errors. Here, the authors achieve high-fidelity coherent state transfer in a Si double quantum dot, underpinning the prospects of a large-scale quantum computer.

Scalable optics co-fabricated with a cryogenic surface-electrode ion trap are used to drive high-fidelity multi-ion quantum logic gates, demonstrating a route to simultaneously scale and reduce errors in quantum processors.

Accurately characterizing the noise influencing quantum devices is instrumental to improve coherence properties and design more robust control protocols. Sung et al. demonstrate non-Gaussian noise spectroscopy with a superconducting qubit, enabling the detection and characterization of dephasing noise without assuming Gaussian statistics.

Readout of a superconducting qubit embedded in a circuit quantum electrodynamics architecture is demonstrated at optical frequencies through a low-noise electro-optomechanical transducer.

CMOS-based circuits can be integrated with silicon-based spin qubits and can be controlled at milli-kelvin temperatures, which can potentially help scale up these systems.

Coupling advances in socioeconomic projections, climate models, damage functions and discounting methods yields an estimate of the social cost of carbon of US$185 per tonne of CO₂—triple the widely used value published by the US government.

Silicon spin qubits can be fabricated in a 300 mm semiconductor manufacturing facility using all-optical lithography and fully industrial processing.

Extending matter-wave interferometry to nanoscale objects requires beam splitters that can cope with their internal complexity. Here, the authors demonstrate that the absorption of individual photons allows the center-of-mass coherence of large molecules to be maintained.

The precision of interferometers — used in metrology and in the state-of-the-art time standard — is generally limited by classical statistics. Here it is shown that the classical precision limit can be beaten by using nonlinear atom interferometry with Bose–Einstein condensates.

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%.

A two-qubit quantum processor in a silicon device is demonstrated, which can perform the Deutsch–Josza algorithm and the Grover search algorithm.

The ability of individual ions trapped in separate potential wells to simulate spin–spin interactions is demonstrated by tuning the Coulomb interaction between two ions, independently controlling their local wells and entangling their internal states with a fidelity of approximately 0.82.

The quantum light–matter interaction between a superconducting artificial atom and squeezed vacuum reduces the transverse radiative decay rate of the atom by a factor of two, allowing the corresponding coherence time, T₂, to exceed the ordinary vacuum decay limit, 2T₁.

Some theories predict that fundamental constants may depend on time, position or the local density of matter. Truppe et al.compare new precise frequency measurements of microwave transitions in cold CH with Milky Way data, placing a new limit on variation in the fine structure constant.

Electrical detection and coherent manipulation of a single ³¹P nuclear spin qubit is reported; the high fidelities are promising for fault-tolerant nuclear-spin-based quantum computing using silicon.

A spatially distributed, atomic clock network entangled via quantum nondemolition measurements offers better precision and lower noise compared to an equivalent mode-separable network, and the improvements scale with network size.

Trapped ions are promising for electrometry but limited by their weak intrinsic spin coupling to electric fields. Now it is shown that using a magnetic field gradient enhances sensitivity and enables precise measurements across subhertz to kilohertz frequencies.

Qutrits, or quantum three-level systems, can provide advantages over qubits in certain quantum information applications, and high-fidelity single-qutrit gates have been demonstrated. Goss et al. realize high-fidelity entangling gates between two superconducting qutrits that are universal for ternary computation.

The hybrid architecture of Andreev spin qubits made using semiconductor–superconductor nanowires means that supercurrents can be used to inductively couple qubits over long distances.