Mixed Species Gates

  • Vera M. SchäferEmail author
Part of the Springer Theses book series (Springer Theses)


Entangling ions of different species is an important prerequisite for transferring quantum information between them. Thus we can choose to perform operations on the best suited species, harnessing their individual strengths. We use the \(\sigma _z\) geometric phase gate that only requires a single pair of Raman beams to perform a gate simultaneously on two different species. In a first test of the scheme we perform the gate between two different isotopes of calcium: \(^{40}\mathrm {Ca}^+\) and \(^{43}\mathrm {Ca}^+\). These results were published in [1] and are also discussed in parts in [2]. In a proof-of-principle experiment we then realise the same gate on two different atomic species—\(^{43}\mathrm {Ca}^+\) and \(^{88}\mathrm {Sr}^+\).


  1. 1.
    Ballance CJ et al (2015) Hybrid quantum logic and a test of Bell’s inequality using two different atomic isotopes. Nature 528:384–386. ISSN: 0028-0836Google Scholar
  2. 2.
    Ballance CJ (2014) High-fidelity quantum logic in Ca + PhD thesis, University of OxfordGoogle Scholar
  3. 3.
    Szwer D (2010) High fidelity readout and protection of a 43Ca+ trapped ion qubit PhD thesis, University of Oxford. papers://d311e016-dabd-41c6-98d5-71ce9eddf36c/Paper/p1856Google Scholar
  4. 4.
    Lucas DM et al (2004) Isotope-selective photoionization for calcium ion trapping. Phys Rev A 69:012711. ISSN: 1050-2947Google Scholar
  5. 5.
    Linke NM, Ballance CJ, Lucas DM (2013) Injection locking of two frequency doubled lasers with 3.2 GHz offset for driving Raman transitions with low photon scattering in 43Ca+. Opt Lett 38:5087–5089Google Scholar
  6. 6.
    McDonnell MJ, Stacey DN, Steane AM (2004) Laser linewidth effects in quantum state discrimination by electromagnetically induced transparency. Phys Rev A 70:053802. ISSN: 10502947Google Scholar
  7. 7.
    Ballance CJ, Harty TP, Linke NM, Sepiol MA, Lucas DM (2016) High-fidelity quantum logic gates using trapped-ion hyperfine qubits. Phys Rev Lett 117:060504. ISSN: 10797114Google Scholar
  8. 8.
    Bell JS (1964) On the Einstein Podolsky Rosen paradox. Physics 1:195–200MathSciNetCrossRefGoogle Scholar
  9. 9.
    Lanyon BP et al (2014) Experimental violation of multipartite Bell inequalities with trapped ions. Phys Rev Lett 112:100403. ISSN: 0031-9007Google Scholar
  10. 10.
    Freedman SJ, Clauser JF (1972) Experimental test of local hidden-variable theories. Phys Rev Lett 28:938–941ADSCrossRefGoogle Scholar
  11. 11.
    Hensen B et al (2015) Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometres. Nature 526:682–686. ISSN: 0028-0836Google Scholar
  12. 12.
    Brunner N, Cavalcanti D, Pironio S, Scarani V, Wehner S (2014) Bell nonlocality. Rev Mod Phys 86:419–478. ISSN: 15390756Google Scholar
  13. 13.
    Rowe MA et al (2001) Experimental violation of a Bell’s inequality with efficient detection. Nature 409:791–794ADSCrossRefGoogle Scholar
  14. 14.
    Clauser JF, Horne MA, Shimony A, Holt RA (1969) Proposed experiment to test local hidden-variable theories. Phys Rev Lett 23:880–884. ISSN: 03759601Google Scholar
  15. 15.
    Matsukevich DN, Maunz P, Moehring DL, Olmschenk S, Monroe C (2008) Bell inequality violation with two remote atomic qubits. Phys Rev Lett 100:150404. ISSN: 0031-9007Google Scholar

Copyright information

© Springer Nature Switzerland AG 2020

Authors and Affiliations

  1. 1.Clarendon Laboratory, Department of PhysicsUniversity of OxfordOxfordUK

Personalised recommendations