[
    {
        "id": "authors:jatnv-n6p95",
        "collection": "authors",
        "collection_id": "jatnv-n6p95",
        "cite_using_url": "https://authors.library.caltech.edu/records/jatnv-n6p95",
        "type": "article",
        "title": "Quantum state preparation with optimal T-count",
        "author": [
            {
                "family_name": "Gosset",
                "given_name": "David",
                "orcid": "0000-0003-3975-2253"
            },
            {
                "family_name": "Kothari",
                "given_name": "Robin",
                "orcid": "0000-0001-6114-943X"
            },
            {
                "family_name": "Wu",
                "given_name": "Kewen",
                "orcid": "0000-0002-5894-822X",
                "clpid": "Wu-Kewen"
            }
        ],
        "abstract": "<p>How many T gates are needed to approximate an arbitrary n -qubit quantum state to within error &epsilon; ? Improving prior work of Low, Kliuchnikov, and Schaeffer, we show that the optimal asymptotic scaling is &Theta; ( 2 n log \u2061 ( 1 / &epsilon; ) + log \u2061 ( 1 / &epsilon; ) ) if we allow ancilla qubits. We also show that this is the optimal T -count for implementing an arbitrary diagonal n -qubit unitary to within error &epsilon; . We describe applications in which a tensor product of many single-qubit unitaries can be synthesized in parallel for the price of one.</p>",
        "doi": "10.22331/q-2026-07-22-2168",
        "issn": "2521-327X",
        "publisher": "Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften",
        "publication": "Quantum",
        "publication_date": "2026-07-22",
        "volume": "10",
        "pages": "2168"
    }
]