Speaker
Description
The complexity and variety of molecules offer opportunities for metrology and quantum information that go beyond what is possible with atomic systems. The hydrogen molecular ion is the simplest of all molecules and can thus be calculated ab initio to very high precision [1]. Combined with spectroscopy this allows to determine fundamental constants and test fundamental theory at record precision [2–4]. Spectroscopy of H$^+_2$ should improve substantially by performing experiments with single hydrogen molecular ions, reducing systematic uncertainties and improving signal strength. This necessitates quantum control.
I will present our progress towards full quantum control of a single hydrogen molecular ion. Our most recent results demonstrate the co-trapping and cooling of single H$^+_2$ and $^9$Be$^+$ ions. The experimental apparatus features a cryogenic ultra-high vacuum chamber, housing a micro-fabricated monolithic linear Paul trap. H$^+_2$ is loaded into the trap by electron bombardment of H$_2$. We aim to use He buffer gas cooling in combination with quantum logic spectroscopy to initialize the internal state of H$^+_2$ in a pure quantum state and implement non-destructive readout [5-9].
[1] V. I. Korobov, J.-P. Karr, M. Haidar, and Z.-X. Zhong, “Hyperfine structure in the H+2 and HD+ molecular ions at order m 6,” Phys. Rev. A, vol. 102, p. 022804, Aug 2020.
[2] S. Alighanbari, G. S. Giri, F. L. Constantin, V. I. Korobov, and S. Schiller, “Precise test of quantum electrodynamics and determination of fundamental constants with HD+ ions,” Nature, vol. 581, no. 7807, pp. 152–158, 2020.
[3] S. Patra, M. Germann, J.-P. Karr, M. Haidar, L. Hilico, V. I. Korobov, F. M. J. Cozijn, K. S. E. Eikema, W. Ubachs, and J. C. J. Koelemeij, “Proton-electron mass ratio from laser spectroscopy of HD+ at the part-per-trillion level,” Science, vol. 369, no. 6508, pp. 1238–1241, 2020.
[4] I. V. Kortunov, S. Alighanbari, M. G. Hansen, G. S. Giri, V. I. Korobov, and S. Schiller, “Proton–electron mass ratio by high-resolution optical spectroscopy of ion ensembles in the resolved-carrier regime,” Nature Physics, 2021.
[5] S. Schiller, I. Kortunov, M. Hernández Vera, F. Gianturco, and H. da Silva, “Quantum state preparation of homonuclear molecular ions enabled via a cold buffer gas: An ab initio study for the H+2 and the D+2 case,” Phys. Rev. A, vol. 95, p. 043411, Apr 2017.
[6] P. O. Schmidt, T. Rosenband, C. Langer, W. M. Itano, J. C. Bergquist, and D. J. Wineland, “Spectroscopy using quantum logic,” Science, vol. 309, pp. 749–752, 2005.
[7] F. Wolf, Y. Wan, J. C. Heip, F. Gebert, C. Shi, and P. O. Schmidt, “Non-destructive state
detection for quantum logic spectroscopy of molecular ions," Nature, vol. 530, no. 7591, pp. 457-460, 2016.
[8] C.-W. Chou, C. Kurz, D. B. Hume, P. N. Plessow, D. R. Leibrandt, and D. Leibfried, “Preparation and coherent manipulation of pure quantum states of a single molecular ion," Nature, vol. 545, pp. 203-207, 2017.
[9] M. Sinhal, Z. Meir, K. Naja an, G. Hegi, and S. Willitsch, “Quantum-nondemolition state detection and spectroscopy of single trapped molecules," Science, vol. 367, no. 6483, pp. 1213-1218, 2020.
