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Efficient sympathetic cooling in mixed barium and ytterbium ion chains


We study sympathetic cooling of the radial ion motion in a linear RF trap in mixed barium-ytterbium chains. Barium ions are Doppler-cooled, while ytterbium ions are cooled through their interaction with cold barium ions. We estimate the efficiency of sympathetic cooling by measuring the average occupation quantum numbers, and thus the temperature, of all radial normal modes of motion in the ion chain. The full set of orderings in a chain of two barium and two ytterbium ions have been probed, and we show that the average thermal occupation numbers for all chain configurations strongly depend on the trap aspect ratio. We demonstrate efficient sympathetic cooling of all radial normal modes for the trap aspect ratio of approximately 2.9.

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  1. Häffner, H., Roos, C., Blatt, R.: Quantum computing with trapped ions. Phys. Rep. 469(4), 155 (2008)

    MathSciNet  Article  ADS  Google Scholar 

  2. Cirac, J.I., Zoller, P.: Quantum computations with cold trapped ions. Phys. Rev. Lett. 74, 4091 (1995).

    Article  ADS  Google Scholar 

  3. Moehring, D.L., Maunz, P., Olmschenk, S., Younge, K.C., Matsukevich, D.N., Duan, L.M., Monroe, C.: Entanglement of single-atom quantum bits at a distance. Nature (2007).

    Article  Google Scholar 

  4. Monroe, C., Raussendorf, R., Ruthven, A., Brown, K.R., Maunz, P., Duan, L.M., Kim, J.: Large-scale modular quantum-computer architecture with atomic memory and photonic interconnects. Phys. Rev. A 89, 022317 (2014).

    Article  ADS  Google Scholar 

  5. Rajagopal, V., Marler, J.P., Kokish, M.G., Odom, B.C.: Trapped ion chain thermometry and mass spectrometry through imaging. Eur. J. Mass Spectrom. 22(1), 1 (2016).

    Article  Google Scholar 

  6. Chen, J.S., Brewer, S.M., Chou, C.W., Wineland, D.J., Leibrandt, D.R., Hume, D.B.: Sympathetic ground state cooling and time-dilation shifts in an \({^{27}\rm Al}^{+}\) optical clock. Phys. Rev. Lett. 118, 053002 (2017).

    Article  Google Scholar 

  7. Rohde, H., Gulde, S.T., Roos, C.F., Barton, P.A., Leibfried, D., Eschner, J., Schmidt-Kaler, F., Blatt, R.: Sympathetic ground-state cooling and coherent manipulation with two-ion crystals. J. Opt. B Quantum Semiclass. Opt. 3(1), S34 (2001)

    Article  ADS  Google Scholar 

  8. Sugiyama, K.: Laser cooling of single 174 Yb + ions stored in a RF. Trap. Jpn. J. Appl. Phys. 38(4R), 2141 (1999)

    Article  ADS  Google Scholar 

  9. Blinov, B.B., Deslauriers, L., Lee, P., Madsen, M.J., Miller, R., Monroe, C.: Sympathetic cooling of trapped Cd\(^{+}\) isotopes. PRA 65(4), 040304 (2002).

    Article  Google Scholar 

  10. Hucul, D., Inlek, I.V., Vittorini, G., Crocker, C., Debnath, S., Clark, S.M., Monroe, C.: Modular entanglement of atomic qubits using photons and phonons. Nat. Phys. 11, 37 (2014).

    Article  Google Scholar 

  11. Home, J.P., McDonnell, M.J., Szwer, D.J., Keitch, B.C., Lucas, D.M., Stacey, D.N., Steane, A.M.: Memory coherence of a sympathetically cooled trapped-ion qubit. Phys. Rev. A 79(5), 050305 (2009).

    Article  ADS  Google Scholar 

  12. Wang, Y., Um, M., Zhang, J., An, S., Lyu, M., Zhang, J.N., Duan, L.M., Yum, D., Kim, K.: Single qubit quantum memory exceeding ten-minute coherence time. Nat. Photon. (2017).

    Article  Google Scholar 

  13. Wübbena, J.B., Amairi, S., Mandel, O., Schmidt, P.O.: Sympathetic cooling of mixed-species two-ion crystals for precision spectroscopy. Phys. Rev. A 85, 043412 (2012).

    Article  ADS  Google Scholar 

  14. Lin, G.-D., Zhu, S.-L., Islam, R., Kim, K., Chang, M.-S., Korenblit, S., Monroe, C., Duan, L.-M.: Large-scale quantum computation in an anharmonic linear ion trap. EPL 86(6), 60004 (2009).

    Article  ADS  Google Scholar 

  15. Zhu, S.L., Monroe, C., Duan, L.M.: Trapped ion quantum computation with transverse phonon modes. Phys. Rev. Lett. 97, 050505 (2006).

    Article  ADS  Google Scholar 

  16. Bentley, C.D.B., Carvalho, A.R.R., Hope, J.J.: Trapped ion scaling with pulsed fast gates. New J. Phys. 17(10), 103025 (2015)

    Article  ADS  Google Scholar 

  17. Kielpinski, D., King, B.E., Myatt, C.J., Sackett, C.A., Turchette, Q.A., Itano, W.M., Monroe, C., Wineland, D.J., Zurek, W.H.: Sympathetic cooling of trapped ions for quantum logic. Phys. Rev. A 61, 032310 (2000).

    Article  ADS  Google Scholar 

  18. Turchette, Q.A., Kielpinski, B.E., King, D., Leibfried, D.M., Meekhof, C.J., Myatt, M.A., Rowe, C.A., Sackett, C.S., Wood, W.M., Itano, C., Monroe, D.J. Wineland.: Heating of trapped ions from the quantum ground state. Phys. Rev. A 61, 063418 (2000).

    Article  ADS  Google Scholar 

  19. Safavi-Naini, A., Rabl, P., Weck, P.F., Sadeghpour, H.R.: Microscopic model of electric-field-noise heating in ion traps. Phys. Rev. A 84, 023412 (2011).

    Article  ADS  Google Scholar 

  20. Dietrich, M.R., Kurz, N., Noel, T., Shu, G., Blinov, B.B.: Hyperfine and optical barium ion qubits. Phys. Rev. A 81, 052328 (2010)

    Article  ADS  Google Scholar 

  21. Wright, J., Auchter, C., Chou, C.K., Graham, R.D., Noel, T.L.W., Sakrejda, T., Zhou, Z., Blinov, B.B.: Toward a scalable quantum computing architecture with mixed species ion chains. Quantum Inf. Process. 15, 5339 (2016)

    Article  ADS  Google Scholar 

  22. Noel, T., Dietrich, M.R., Kurz, N., Shu, G., Wright, J., Blinov, B.B.: Adiabatic passage in the presence of noise. Phys. Rev. A 85, 023401 (2012).

    Article  ADS  Google Scholar 

  23. Wright, J.: Phd thesis. Ph.D. thesis, University of Washington (2015)

  24. Janik, G., Nagourney, W., Dehmelt, H.: Doppler-free optical spectroscopy on the Ba\(+\) mono-ion oscillator. J. Opt. Soc. Am. B 2(8), 1251 (1985).

    Article  Google Scholar 

  25. Lin, Y., Gaebler, J.P., Tan, T.R., Bowler, R., Jost, J.D., Leibfried, D., Wineland, D.J.: Sympathetic electromagnetically-induced-transparency laser cooling of motional modes in an ion chain. Phys. Rev. Lett. 110, 153002 (2013).

    Article  ADS  Google Scholar 

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The authors wish to thank John Wright and Wen-Lin Tan for help with earlier parts of the experiments, and Megan Ivory, Jennifer Lilieholm, Alexander Pierce, Ramya Bhaskar and James Walker Steere for helpful discussions. This research was supported by National Science Foundation Grant No. 1505326.Tomasz P. Sakrejda and Liudmila A. Zhukas contributed equally to this manuscript.

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Correspondence to Liudmila A. Zhukas.

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Sakrejda, T.P., Zhukas, L.A. & Blinov, B.B. Efficient sympathetic cooling in mixed barium and ytterbium ion chains. Quantum Inf Process 20, 162 (2021).

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  • Trapped ions
  • Doppler cooling
  • Sympathetic cooling
  • Trap aspect ratio