[
    {
        "id": "authors:52d3w-r3f96",
        "collection": "authors",
        "collection_id": "52d3w-r3f96",
        "cite_using_url": "https://authors.library.caltech.edu/records/52d3w-r3f96",
        "type": "monograph",
        "title": "Multi-qubit gates and 'Schr\u00f6dinger cat' states in an optical clock",
        "author": [
            {
                "family_name": "Cao",
                "given_name": "Alec",
                "orcid": "0000-0002-6111-1375",
                "clpid": "Cao-Alec"
            },
            {
                "family_name": "Eckner",
                "given_name": "William J.",
                "orcid": "0000-0003-0833-7137",
                "clpid": "Eckner-William-J"
            },
            {
                "family_name": "Lukin Yelin",
                "given_name": "Theodor",
                "orcid": "0009-0000-7295-5701",
                "clpid": "Lukin-Yelin-Theodor"
            },
            {
                "family_name": "Young",
                "given_name": "Aaron W.",
                "orcid": "0000-0002-3490-4046",
                "clpid": "Young-Aaron-W"
            },
            {
                "family_name": "Jandura",
                "given_name": "Sven",
                "orcid": "0000-0003-0282-7637",
                "clpid": "Jandura-Sven"
            },
            {
                "family_name": "Yan",
                "given_name": "Lingfeng",
                "clpid": "Yan-Lingfeng"
            },
            {
                "family_name": "Kim",
                "given_name": "Kyungtae",
                "orcid": "0000-0001-5428-6700",
                "clpid": "Kim-Kyungtae"
            },
            {
                "family_name": "Pupillo",
                "given_name": "Guido",
                "orcid": "0000-0002-1549-0386",
                "clpid": "Pupillo-Guido"
            },
            {
                "family_name": "Ye",
                "given_name": "Jun",
                "clpid": "Ye-Jun"
            },
            {
                "family_name": "Darkwah Oppong",
                "given_name": "Nelson",
                "orcid": "0000-0002-2114-6848",
                "clpid": "Darkwah-Oppong-N"
            },
            {
                "family_name": "Kaufman",
                "given_name": "Adam M.",
                "orcid": "0000-0003-4956-5814",
                "clpid": "Kaufman-Adam-M"
            }
        ],
        "abstract": "<p>Many-particle entanglement is a key resource for achieving the fundamental precision limits of a quantum sensor. Optical atomic clocks, the current state-of-the-art in frequency precision, are a rapidly emerging area of focus for entanglement-enhanced metrology. Augmenting tweezer-based clocks featuring microscopic control and detection with the high-fidelity entangling gates developed for atom-array information processing offers a promising route towards leveraging highly entangled quantum states for improved optical clocks. Here we develop and employ a family of multi-qubit Rydberg gates to generate 'Schr&ouml;dinger cat' states of the Greenberger-Horne-Zeilinger (GHZ) type with up to 9 optical clock qubits in a programmable atom array. In an atom-laser comparison at sufficiently short dark times, we demonstrate a fractional frequency instability below the standard quantum limit using GHZ states of up to 4 qubits. A key challenge to improving the optimal achievable clock precision with GHZ states is their reduced dynamic range. Towards overcoming this hurdle, we simultaneously prepare a cascade of varying-size GHZ states to perform unambiguous phase estimation over an extended interval. These results demonstrate key building blocks for approaching Heisenberg-limited scaling of optical atomic clock precision.</p>",
        "doi": "10.48550/arxiv.2402.16289",
        "publisher": "arXiv",
        "publication_date": "2024-02-26"
    }
]