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The acoustic Purcell effect is observed by constructing a specially engineered, microwave-frequency nanomechanical resonator around a colour centre spin qubit in diamond.

Multielectron quantum dots offer a promising platform for high-performance spin qubits; however, previous demonstrations have been limited to single-qubit operation. Here, the authors report a universal gate set and two-qubit Bell state tomography in a high-occupancy double quantum dot in silicon.

A single electron spin in silicon is dressed by a microwave field to create a new qubit with tangible advantages for quantum computation and nanoscale research.

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.

Hole spin qubits in germanium have seen significant advancements, though improving control and noise resilience remains a key challenge. Here, the authors realize a dressed singlet-triplet qubit in germanium, achieving frequency-modulated high-fidelity control and a tenfold increase in coherence time.

The coherent operation of individual ³¹P electron and nuclear spin qubits in a ²⁸Si substrate shows new benchmark decoherence times and provides essential information on the dechorence mechanism.

Global control of a qubits using a single microwave field is a promising strategy for scalable quantum computing. Here the authors demonstrate individual addressability vial local electrodes and two-qubit gates in an array of Si quantum dot spin qubits dressed by a global microwave field and driven on-resonance.

Donors spins in silicon are coherent, high-performance qubits, but scale-up has been challenging. Here the authors present the first experimental demonstration of exchange-based, entangling two qubit gates between electrons bound to ³¹P donors in Si.

For solid-state qubits, the material environment hosts sources of errors that vary in time and space. This systematic analysis of errors affecting high-fidelity two-qubit gates in silicon can inform the design of large-scale quantum computers.

A high-fidelity two-qubit CNOT logic gate is presented, which is realized by combining single- and two-qubit operations with controlled phase operations in a quantum dot system using the exchange interaction.

Initialization and operation of spin qubits in silicon above 1 K reach fidelities sufficient for fault-tolerant operations at these temperatures.

A violation of Bell's inequality, which is a direct proof of entanglement, can be observed in the solid state using the electron and nuclear spins of a single phosphorus atom in silicon.

High-performance all-electrical control is a prerequisite for scalable silicon quantum computing. The switchable interaction between spins and orbital motion of electrons in silicon quantum dots now enables the electrical control of a spin qubit with high fidelity and speed, without the need for integrating a micromagnet.

Understanding the microscopic variability of CMOS spin qubits is crucial for developing scalable quantum processors. Here the authors report a combined experimental and numerical study of the effect of interface roughness on variability of quantum dot spin qubits formed at the Si/SiO₂ interface.

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.

Operating donor-based quantum computers in silicon is hindered by the dependence of inter-qubit coupling on the precise donor position. Here, the authors show controlled rotation operation on exchange-coupled electron spins in the weak-exchange regime, loosening the requirements on positioning precision.

Quantum dots are often referred to as “artificial atoms” as they create zero-dimensional traps for electrons, with characteristic atom-like spectra. Leon et al. demonstrate that higher shell and orbital states of a multi-electron silicon quantum dot with better control fidelity than single electron dots.

Coherent quantum control of a single ¹²³Sb nucleus using electric fields produced within a silicon nanoelectronic device is demonstrated experimentally, validating a concept predicted theoretically in 1961.

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.

One of the main sources of decoherence in silicon electron spin qubits is their interaction with nearby fluctuating nuclear spins. Zhao et al. present a device made from enriched silicon to reduce the nuclear spin density and find its performance is still limited by fluctuations of residual spins.

Pulse engineering techniques can be used to reduce the average Clifford gate error rates for silicon quantum dot spin qubits down to 0.043%, a factor of three improvement over state-of-the-art silicon devices.

Significant progress has been made developing the different methods needed for a spin-based quantum computer but the challenge of integrating them remains. Fogarty et al. present a system with single-spin addressability, spin-spin interactions and high-fidelity readout that provides a scalable foundation for error-corrected devices.

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.

In a birth cohort, Holz et al. found widespread structural brain changes at the age of 25 years as a function of adversity. This pattern was replicated at the age of 33 years and in another cohort. Individual-level volume reductions on top of this pattern predicted anxiety.

An inequality is shown to exist between the spectral directional emissivity and absorptivity in a structure supporting a guided-mode resonance coupled to a magneto-optic material. This finding provides the direct observation of the violation of Kirchhoff’s law of thermal radiation.

Quantum computing requires fast and selective control of a large number of individual qubits while maintaining coherence, which is hard to achieve concomitantly. All-electrical operation of a hole spin qubit in a Ge/Si nanowire demonstrates the principle of switching from a mode of selective and fast control to idling with increased coherence.

In one-dimensional systems, the combination of a strong spin-orbit interaction and an applied magnetic field can give rise to a spin-gap, however experimental identification is difficult. Here, the authors present new signatures for the spin-gap, and verify these experimentally in hole QPCs.

Nuclear spins are excellent qubits, but long-range interactions are difficult to establish. Here, the authors couple a ²⁹Si nuclear spin to electrons in a lithographically defined quantum dot and show initialization, readout and entanglement with the electron spin. The ²⁹Si retains its coherence under electron transfer between quantum dots.

Quantum computers will require a large network of coherent qubits, connected in a noise-resilient way. Tosi et al. present a design for a quantum processor based on electron-nuclear spins in silicon, with electrical control and coupling schemes that simplify qubit fabrication and operation.

The coherent manipulation of an individual electron spin qubit bound to a single phosphorus donor atom in natural silicon provides an excellent platform on which to build a scalable quantum computer.

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.

Two-qubit logic gates in a silicon-based system are shown (using randomized benchmarking) to have high gate fidelities of operation and are used to generate Bell states, a step towards solid-state quantum computation.

Although quantum physics underpins the behaviour of nanoscale objects, its role in nanoscience has been mostly limited to determining the static, equilibrium properties of small systems. This Review describes seminal developments and new directions for the explicit exploitation of quantum coherence in nanoscale systems, a research area termed quantum-coherent nanoscience.

Instead of using capacitively coupled charge sensors, which imply additional complexity in the device architecture, radiofrequency reflectometry on the gate defining the quantum dot can read out the spin state of a double quantum dot in a single shot.

This Review examines the scaling prospects of quantum computing systems based on silicon spin technology and how the different layers of such a computer could benefit from using complementary metal–oxide–semiconductor (CMOS) technology.