Abstract

We give an algorithm for pure state tomography with near-optimal copy complexity using single-qubit measurements. Specifically, given \widetilde{O}(2^n/\epsilon) copies of an unknown pure n-qubit state \lvert\psi\rangle, the algorithm performs only \textit{nonadaptive Pauli measurements}, runs in time \mathrm{poly}(2^n,1/\epsilon), and outputs \lvert \widehat{\psi} \rangle that has fidelity 1-\epsilon with \lvert \psi \rangle with high probability. This improves upon the previous best copy complexity bound of \widetilde{O}(3^n/\epsilon).

Personal information

Sabee Grewal is a PhD student at UT Austin advised by Scott Aaronson and a student researcher at Google Quantum AI. He is interested in quantum algorithms, quantum learning theory, and quantum complexity theory.

Reference

https://arxiv.org/abs/2601.04444