Authors

Ewin Tang

Publications 2

Preprint Open access

Pretty good shadow tomography

We give a shadow tomography algorithm that uses $O(\log(m) \log(m/δ) / \varepsilon^2)$ copies of the input state. Specifically, given a quantum state $ρ$ and observables $O_1,\ldots,O_m$, the algorithm outputs estimates of $\mathrm{tr}(O_iρ)$ for all $i\in[m]$ that are all accurate to within $\pm\varepsilon$, except wi …

Preprint Open access

Unitary complexity in polynomial space

We show that if quantum commitments exist, then either there is no polynomial-time solution to the unitary synthesis problem, or $\mathsf{BPP} \neq \mathsf{NEXP}$. Thus, showing unconditionally that quantum commitments exist would require answering at least one of two longstanding open questions in complexity theory. W …

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