Researchers Achieve Quantum Computing Fidelity Estimate Success

Scientists have made a breakthrough in quantum computing by demonstrating a method to verify the quality of complex quantum computations. Researchers used measurement-based quantum computation, which involves creating a large network of quantum particles, known as a cluster state, and then performing measurements on it.

This approach was led by a team that included researchers from the University of Innsbruck and Google. The experiment used trapped ions to generate a large cluster state with up to 20 qubits, which is a significant step towards achieving a quantum advantage. The team also developed a method for direct fidelity estimation, allowing them to efficiently verify the quality of the computations without running multiple experiments. This breakthrough has implications for companies like Google and IBM, which are developing quantum computing technologies, as well as researchers in the field, including those at the University of Innsbruck.

The authors discuss the importance of verifying the quality of quantum computations, particularly in the context of quantum random sampling experiments. They introduce MBQC as a viable approach for efficient verification.

The paper describes their experimental setup using trapped ions to generate cluster states, which are used for MBQC. They employ qubit recycling to perform large-scale MBQC with a quadratically larger qubits than the physical ion register.

The researchers demonstrate direct fidelity estimation as an efficient means of certifying both single instances and the average quality of measurement-based computations. This method has a sample complexity independent of system size, making it scalable.

The authors present experimental results for average performance verification using direct fidelity estimation, linear XEB (cross-entropy benchmarking), and logarithmic XEB. They compare these estimates to classical predictions based on gate fidelities and measurement errors.

The authors conclude that direct fidelity estimation provides an efficient and scalable means of certifying MBQC computations. They highlight the advantages of MBQC over circuit-based models for verification and discuss potential applications in various quantum computing platforms, including trapped ions, Rydberg atoms, photonics, and continuous-variable optical systems.