High-fidelity operation and algorithmic initialisation of spin qubits above one kelvin

Abstract

The encoding of qubits in semiconductor spin carriers has been recognised as a promising approach to a commercial quantum computer that can be lithographically produced and integrated at scale. However, the operation of the large number of qubits required for advantageous quantum applications will produce a thermal load exceeding the available cooling power of cryostats at millikelvin temperatures. As the scale-up accelerates, it becomes imperative to establish fault-tolerant operation above 1 kelvin, where the cooling power is orders of magnitude higher. Here, we tune up and operate spin qubits in silicon above 1 kelvin, with fidelities in the range required for fault-tolerant operation at such temperatures. We design an algorithmic initialisation protocol to prepare a pure two-qubit state even when the thermal energy is substantially above the qubit energies, and incorporate radio-frequency readout to achieve fidelities up to 99.34 per cent for both readout and initialisation. Importantly, we demonstrate a single-qubit Clifford gate fidelity of 99.85 per cent, and a two-qubit gate fidelity of 98.92 per cent. These advances overcome the fundamental limitation that the thermal energy must be well below the qubit energies for high-fidelity operation to be possible, surmounting a major obstacle in the pathway to scalable and fault-tolerant quantum computation.

References in corpus (63)

• Quantum Computing in the NISQ era and beyond
• Quantum Computation with Quantum Dots
• Surface codes: Towards practical large-scale quantum computation
• Single-shot read-out of an individual electron spin in a quantum dot
• Silicon Quantum Electronics
• Randomized Benchmarking of Quantum Gates
• An addressable quantum dot qubit with fault-tolerant control fidelity
• A >99.9%-fidelity quantum-dot spin qubit with coherence limited by charge noise
• Fault-tolerant quantum computation with high threshold in two dimensions
• Single-shot readout of an electron spin in silicon
• A programmable two-qubit quantum processor in silicon
• Storing quantum information for 30 seconds in a nanoelectronic device
• Interfacing spin qubits in quantum dots and donors - hot, dense and coherent
• Roads towards fault-tolerant universal quantum computation
• How to Enhance Dephasing Time in Superconducting Qubits
• Computing with spin qubits at the surface code error threshold
• Fast universal quantum control above the fault-tolerance threshold in silicon
• Universal control of a six-qubit quantum processor in silicon
• Silicon quantum processor unit cell operation above one Kelvin
• Fidelity benchmarks for two-qubit gates in silicon
• Qubits made by advanced semiconductor manufacturing
• Quantum computing with nearest neighbor interactions and error rates over 1%
• Two-qubit silicon quantum processor with operation fidelity exceeding 99%
• Universal quantum logic in hot silicon qubits
• Spin-valley lifetimes in a silicon quantum dot with tunable valley splitting
• Reduced sensitivity to charge noise in semiconductor spin qubits via symmetric operation
• Blueprint for a microwave trapped-ion quantum computer
• Scaling silicon-based quantum computing using CMOS technology: State-of-the-art, Challenges and Perspectives
• Precision tomography of a three-qubit donor quantum processor in silicon
• Noise suppression using symmetric exchange gates in spin qubits
• Ultrahigh Error Threshold for Surface Codes with Biased Noise
• Silicon qubit fidelities approaching incoherent noise limits via pulse engineering
• A hole spin qubit in a fin field-effect transistor above 4 kelvin
• Scaling of Dynamical Decoupling for Spin Qubits
• Gate-reflectometry dispersive readout and coherent control of a spin qubit in silicon
• Low-frequency spin qubit detuning noise in highly purified ${}^{28}$Si/SiGe
• Pauli Spin Blockade in a Highly Tunable Silicon Double Quantum Dot
• Spin lifetime and charge noise in hot silicon quantum dot qubits
• Fault-tolerant thresholds for the surface code in excess of 5% under biased noise
• Randomized benchmarking of single and multi-qubit control in liquid-state NMR quantum information processing
• A Dressed Spin Qubit in Silicon
• Spin-orbit coupling and operation of multi-valley spin qubits
• Pauli Blockade in Silicon Quantum Dots with Spin-Orbit Control
• Integrated silicon qubit platform with single-spin addressability, exchange control and robust single-shot singlet-triplet readout
• Repetitive single electron spin readout in silicon
• Coherent spin control of s-, p-, d- and f-electrons in a silicon quantum dot
• Single-spin qubits in isotopically enriched silicon at low magnetic field
• High fidelity state preparation, quantum control, and readout of an isotopically enriched silicon spin qubit
• Fast and high-fidelity state preparation and measurement in triple-quantum-dot spin qubits
• On-demand electrical control of spin qubits
• Dynamically controlled charge sensing of a few-electron silicon quantum dot
• Orbital and valley state spectra of a few-electron silicon quantum dot
• The SMART protocol -- Pulse engineering of a global field for robust and universal quantum computation
• Single-electron spin resonance in a nanoelectronic device using a global field
• A taxonomy of small Markovian errors
• Quantum Computation Protocol for Dressed Spins in a Global Field
• Implementation of the SMART protocol for global qubit control in silicon
• Coherent control of electron spin qubits in silicon using a global field
• Fast Bayesian tomography of a two-qubit gate set in silicon
• Beating the thermal limit of qubit initialization with a Bayesian Maxwell's demon
• A high-sensitivity charge sensor for silicon qubits above one kelvin
• Feedback-based active reset of a spin qubit in silicon
• Characterizing non-Markovian Quantum Process by Fast Bayesian Tomography

Cited by in corpus (39)

• A 300 mm foundry silicon spin qubit unit cell exceeding 99% fidelity in all operations
• Artificial Intelligence for Quantum Computing
• Grover's algorithm in a four-qubit silicon processor above the fault-tolerant threshold
• High-fidelity single-spin shuttling in silicon
• Strategies for enhancing spin-shuttling fidelities in Si/SiGe quantum wells with random-alloy disorder
• Compromise-Free Scaling of Qubit Speed and Coherence
• Cross-architecture Tuning of Silicon and SiGe-based Quantum Devices Using Machine Learning
• Modular Autonomous Virtualization System for Two-Dimensional Semiconductor Quantum Dot Arrays
• Single-step high-fidelity three-qubit gates by anisotropic chiral interactions
• Violating Bell's inequality in gate-defined quantum dots
• Impact of electrostatic crosstalk on spin qubits in dense CMOS quantum dot arrays
• Entangling gates on degenerate spin qubits dressed by a global field
• An Integrated Deep-Cryogenic Temperature Sensor in CMOS Technology for Quantum Computing Applications
• Toward Axion Signal Extraction in Semiconductor Spin Qubits Via Spectral Engineering
• Quantum geometric protocols for fast high-fidelity adiabatic state transfer
• A thermal-noise-resilient microwave quantum network traversing 4 K
• All-electrical operation of a spin qubit coupled to a high-Q resonator
• Experimental online quantum dots charge autotuning using neural networks
• A 2x2 quantum dot array in silicon with fully tuneable pairwise interdot coupling
• Compiling the surface code to crossbar spin qubit architectures
• Interplay of Zeeman Splitting and Tunnel Coupling in Coherent Spin Qubit Shuttling
• A diverse set of two-qubit gates for spin qubits in semiconductor quantum dots
• Minimal evolution times for fast, pulse-based state preparation in silicon spin qubits
• Polarimetry With Spins in the Solid State
• Effects of dissipation in reservoir computing using a spin qubit array
• Simultaneous study of acoustic and optic phonon scattering of electrons and holes in undoped $\mathrm{GaAs}$/$\mathrm{A}{\mathrm{l}}_{\mathrm{x}}\mathrm{G}{\mathrm{a}}_{1-\mathrm{x}}\mathrm{As}$ heterostructures
• Variability of hole spin qubits in planar Germanium
• The role of antisymmetric orbitals and electron-electron interactions on the two-particle spin and valley blockade in graphene double quantum dots
• A SWAP Gate for Spin Qubits in Silicon
• Limitations of the $g$-tensor formalism of semiconductor spin qubits
• Characterization of a quantum bus between two driven qubits
• Charge-induced energy shift of a single-spin qubit under a magnetic-field gradient
• Highly Tunable Two-Qubit Interactions in Si/SiGe Quantum Dots by Interchanging the Roles of Qubit-Defining Gates
• Dressed basis sets for the modeling of exchange interactions in double quantum dots
• Phonon-induced frequency shift in semiconductor spin qubits
• Maximizing the nondemolition nature of a quantum measurement via an adaptive readout protocol
• Coupling a ${}^{73}$Ge nuclear spin to an electrostatically defined quantum dot
• Four-state discrimination for a pair of spin qubits via gate reflectometry
• Dispersive detection of single microwave photons with quantum dots