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Klüsener V, Pucher S, Yankelev D, Trautmann J, Spriestersbach F, Filin D, Porsev SG, Safronova MS, Bloch I, Blatt S. Long-Lived Coherence on a μHz Scale Optical Magnetic Quadrupole Transition. PHYSICAL REVIEW LETTERS 2024; 132:253201. [PMID: 38996237 DOI: 10.1103/physrevlett.132.253201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/29/2024] [Indexed: 07/14/2024]
Abstract
We report on the coherent excitation of the ultranarrow ^{1}S_{0}-^{3}P_{2} magnetic quadrupole transition in ^{88}Sr. By confining atoms in a state insensitive optical lattice, we achieve excitation fractions of 97(1)% and observe linewidths as narrow as 58(1) Hz. With Ramsey spectroscopy, we find coherence times of 14(1) ms, which can be extended to 266(36) ms using a spin-echo sequence. We determine the lifetime of the ^{3}P_{2} level for spontaneous emission of magnetic quadrupole radiation to be 110(31) min, confirming long-standing theoretical predictions. These results establish an additional clock transition in strontium and pave the way for applications of the metastable ^{3}P_{2} state in quantum computing and quantum simulations.
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Unnikrishnan G, Ilzhöfer P, Scholz A, Hölzl C, Götzelmann A, Gupta RK, Zhao J, Krauter J, Weber S, Makki N, Büchler HP, Pfau T, Meinert F. Coherent Control of the Fine-Structure Qubit in a Single Alkaline-Earth Atom. PHYSICAL REVIEW LETTERS 2024; 132:150606. [PMID: 38682979 DOI: 10.1103/physrevlett.132.150606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/11/2024] [Indexed: 05/01/2024]
Abstract
We report on the first realization of a novel neutral atom qubit encoded in the spin-orbit coupled metastable states ^{3}P_{0} and ^{3}P_{2} of a single ^{88}Sr atom trapped in an optical tweezer. Raman coupling of the qubit states promises rapid single-qubit rotations on par with the fast Rydberg-mediated two-body gates. We demonstrate preparation, readout, and coherent control of the qubit. In addition to driving Rabi oscillations bridging an energy gap of more than 17 THz using a pair of phase-locked clock lasers, we also carry out Ramsey spectroscopy to extract the transverse qubit coherence time T_{2}. When the tweezer is tuned into magic trapping conditions, which is achieved in our setup by tuning the tensor polarizability of the ^{3}P_{2} state via an external control magnetic field, we measure T_{2}=1.2 ms. A microscopic quantum mechanical model is used to simulate our experiments including dominant noise sources. We identify the main constraints limiting the observed coherence time and project improvements to our system in the immediate future. Our Letter opens the door for a so-far-unexplored qubit encoding concept for neutral atom-based quantum computing.
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Affiliation(s)
- G Unnikrishnan
- 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - P Ilzhöfer
- 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - A Scholz
- 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - C Hölzl
- 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - A Götzelmann
- 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - R K Gupta
- 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - J Zhao
- 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - J Krauter
- 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - S Weber
- Institute for Theoretical Physics III and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - N Makki
- Institute for Theoretical Physics III and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - H P Büchler
- Institute for Theoretical Physics III and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - T Pfau
- 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - F Meinert
- 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
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