Quantum state fidelity estimated with fewer measurements than before
Sublinear Copies Suffice for Fidelity Estimation with Pauli Measurements
Computational Complexity
Summary
Measuring how close a lab-made quantum state is to the ideal target usually requires many measurements. The authors show a way to estimate this closeness, called fidelity, more efficiently using much fewer Pauli measurements than previously known. Their method can work well even when measurement numbers grow slower than the size of the quantum system. This helps make checking quantum devices faster and less resource-intensive.
What this means in practice
- •For quantum hardware engineers: Evaluate the accuracy of quantum states produced by devices using fewer Pauli measurements to save time and effort during testing.
- •For quantum software developers: Use efficient fidelity estimation to verify state preparation in quantum algorithms without extensive measurement overhead.
Authors
Jayadev Acharya, Abhilash Dharmavarapu, Yuhan Liu, Nengkun Yu
Abstract
We present a protocol that estimates the quantum fidelity, up to precision $\varepsilon$, between a known target state and unknown lab-prepared state with sublinear, $o(d^{0.9908}/\varepsilon^2)$, number of Pauli basis measurements.