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Engineering the coupling between molecular spin qubits by coordination chemistry

Nature Nanotechnology volume 4, pages 173–178 (2009)Cite this article

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Abstract

The ability to assemble weakly interacting subsystems is a prerequisite for implementing quantum information processing and generating controlled entanglement. In recent years, molecular nanomagnets have been proposed as suitable candidates for qubit encoding and manipulation. In particular, antiferromagnetic Cr7Ni rings behave as effective spin-1/2 systems at low temperature and show long decoherence times. Here, we show that these rings can be chemically linked to each other and that the coupling between their spins can be tuned by choosing the linker. We also present calculations that demonstrate how realistic microwave pulse sequences could be used to generate maximally entangled states in such molecules.

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Figure 1: Structures of the {Cr7Ni}–link–{Cr7Ni} molecules.
Figure 2: Low-temperature specific heat C of linked and free Cr7Ni rings.
Figure 3: Powder Q-band EPR spectra of free Cr7Ni and linked Cr7Ni–Cu–Cr7Ni.
Figure 4: Simulated generation of GHZ states.

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Change history

  • 17 February 2009

    In the version of this Article originally published online, the caption for Fig. 1 was incorrect. The error has been corrected for all versions.

References

  1. Nielsen, M. A. & Chuang, I. L. Quantum Computation and Quantum Information (Cambridge Univ. Press, 2000).

    Google Scholar 

  2. Pan, J.-W., Bouwmeester, D., Daniell, M., Weinfurter, H. & Zeilinger, A. Experimental test of quantum nonlocality in three-photon Greenberger–Horne–Zeilinger entanglement. Nature 403, 515–519 (2000).

    Article  CAS  Google Scholar 

  3. Zhao, Z. et al. Experimental demonstration of five-photon entanglement and open-destination teleportation. Nature 430, 54–58 (2004).

    Article  CAS  Google Scholar 

  4. Sackett, C. A. et al. Experimental entanglement of four particles. Nature 404, 256–259 (2000).

    Article  CAS  Google Scholar 

  5. Roos, C. F. et al. Control and measurement of three-qubit entangled states. Science 304, 1478–1481 (2004).

    Article  CAS  Google Scholar 

  6. Petta, J. R. et al. Coherent manipulation of coupled electron spins in semiconductor quantum dots. Science 309, 2180–2184 (2005).

    Article  CAS  Google Scholar 

  7. Steffen, M. et al. Measurement of the entanglement of two superconducting qubits via state tomography. Science 313, 1423–1425 (2006).

    Article  CAS  Google Scholar 

  8. Leuenberger, M. & Loss, D. Quantum computing in molecular magnets. Nature 410, 789–793 (2001).

    Article  CAS  Google Scholar 

  9. Meier, F., Levy, J. & Loss, D. Quantum computing with spin cluster qubits. Phys. Rev. Lett. 90, 047901 (2003).

    Article  Google Scholar 

  10. Meier, F., Levy, J. & Loss, D. Quantum computing with antiferromagnetic spin clusters. Phys. Rev. B 68, 134417 (2003).

    Article  Google Scholar 

  11. Troiani, F. et al. Molecular engineering of antiferromagnetic rings for quantum computation. Phys. Rev. Lett. 94, 207208 (2005).

    Article  CAS  Google Scholar 

  12. Lehmann, J., Gaita-Ariño, A., Coronado, E. & Loss, D. Spin qubits with electrically gated polyoxometalate molecules. Nature Nanotech. 2, 312–317 (2007).

    Article  CAS  Google Scholar 

  13. Wernsdorfer, W. Molecular magnets: A long-lasting phase. Nature Mater. 6, 174–176 (2007).

    Article  CAS  Google Scholar 

  14. Bogani, L. & Wernsdorfer, W. Molecular spintronics using single molecule magnets. Nature Mater. 7, 179–186 (2008).

    Article  Google Scholar 

  15. Gatteschi, D., Sessoli, R. & Villain, J. Molecular Nanomagnets (Oxford Univ. Press, 2007).

    Google Scholar 

  16. Ardavan, A. et al. Will spin relaxation times in molecular magnets permit quantum information processing? Phys. Rev. Lett. 98, 057201 (2007).

    Article  Google Scholar 

  17. Bertaina, S. et al. Quantum oscillations in a molecular magnet. Nature 453, 203–206 (2008).

    Article  CAS  Google Scholar 

  18. Wernsdorfer, W., Aliaga-Alcalde, N., Hendrickson, D. N. & Christou, G. Exchange-biased quantum tunnelling in a supramolecular dimer of single-molecule magnets. Nature 416, 406–408 (2002).

    Article  Google Scholar 

  19. Hill, S., Edwards, R. S., Aliaga-Alcalde, N. & Christou, G. Quantum coherence in an exchange-coupled dimer of single-molecule magnets. Science 302, 1015–1018 (2003).

    Article  CAS  Google Scholar 

  20. Larsen, F. K. et al. Synthesis and characterization of heterometallic {Cr7M} wheels. Angew. Chem. Int. Ed. 42, 101–105 (2003).

    Article  CAS  Google Scholar 

  21. Carretta, S. et al. Topology and spin dynamics in magnetic molecules. Phys. Rev. B 72, 060403 (2005).

    Article  Google Scholar 

  22. Caciuffo, R. et al. Spin dynamics of heterometallic Cr7M wheels (M = Mn, Zn, Ni) probed by inelastic neutron scattering. Phys. Rev. B 71, 174407 (2005).

    Article  Google Scholar 

  23. Carretta, S. et al. Quantum oscillations of the total spin in a heterometallic antiferromagnetic ring: evidence from neutron spectroscopy. Phys. Rev. Lett. 98, 167401 (2007).

    Article  CAS  Google Scholar 

  24. Troiani, F., Affronte, M., Carretta, S., Santini, P. & Amoretti, G. Proposal for quantum-gate in permanently coupled AF spin rings, without need of local fields. Phys. Rev. Lett. 94, 190501 (2005).

    Article  Google Scholar 

  25. Troiani, F., Bellini, V. & Affronte, M. Decoherence induced by hyperfine interactions with nuclear spins in antiferromagnetic molecular rings. Phys. Rev. B 77, 054428 (2008).

    Article  Google Scholar 

  26. Corradini, V. et al. Isolated heterometallic Cr7Ni rings grafted on Au(111) surface. Inorg. Chem. 46, 4937–4943 (2007).

    Article  CAS  Google Scholar 

  27. Affronte, M. et al. Linking rings through diamines and clusters: exploring synthetic methods for making magnetic quantum gates. Angew. Chem. Int. Ed. 44, 6496–6500 (2005).

    Article  CAS  Google Scholar 

  28. Dür, W., Vidal, G. & Cirac, J. I. Three qubits can be entangled in two inequivalent ways. Phys. Rev. A 62, 062314 (2000).

    Article  Google Scholar 

  29. Röthlisberger, B., Lehmann, J., Saraga, D. S., Traber, P. & Loss, D. Highly entangled ground states in tripartite qubit systems. Phys. Rev. Lett. 100, 100502 (2008).

    Article  Google Scholar 

  30. Laflamme, R., Knill, E., Zurek, W. H., Catasti, P. & Mariappan, S. V. S. NMR Greenberger–Horne–Zeilinger states. Phil. Trans. R. Soc. Lond. A 356, 1941–1948 (1998).

    Article  CAS  Google Scholar 

  31. Carretta, S., Santini, P., Amoretti, G., Troiani, F. & Affronte, M. Spin triangles as optimal units for molecule-based quantum gates. Phys. Rev. B 76, 024408 (2007).

    Article  Google Scholar 

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Acknowledgements

This work was supported by the European Community through the Network of Excellence Molecular Approach to Nanomagnets and Multifunctional Materials (MAGMANet), contract N.515767 and the ICT-FET Open Project Molecular Spin Clusters for Quantum Information Processes (MolSpinQIP), contract N. 211284, by the Engineering and Physical Sciences Research Council (EPSRC) (UK), and by Progetti di Interesse Nazionale (PRIN) 2006029518 (IT). F.T. (Modena) was supported by Fondo per gli Investimenti della Ricerca di Base (FIRB) Contract RBIN01EY74.

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Authors and Affiliations

  1. The Lewis Magnetism Laboratory, School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK

    Grigore A. Timco, Floriana Tuna, Robin J. Pritchard, Christopher A. Muryn, Eric J. L. McInnes & Richard E. P. Winpenny

  2. Dipartimento di Fisica, Università di Parma, v. G.P. Usberti n. 7/A, Parma, 43100, Italy

    Stefano Carretta, Paolo Santini & Giuseppe Amoretti

  3. CNR-INFM-S3 National Research Centre, via G. Campi 213/A, Modena, 41100, Italy

    Filippo Troiani, Alberto Ghirri, Andrea Candini & Marco Affronte

  4. Dipartimento di Fisica, Università di Modena e Reggio Emilia, via G. Campi 213/A, Modena, 41100, Italy

    Alberto Ghirri & Marco Affronte

Authors
  1. Grigore A. Timco
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  2. Stefano Carretta
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  12. Marco Affronte
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  13. Richard E. P. Winpenny
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Contributions

The key idea to use Cr7Ni spin systems for quantum processes was jointly developed by the Manchester, Modena and Parma leaders. F. Troiani, S.C., P.S. and G.A. contributed with modelling, numerical simulations and development of quantum schemes. A.G. and A.C. performed specific heat and magnetic measurements; in addition to these, M.A. contributed with data analysis. G.T. made the compounds after discussion with R.E.P.W. F. Tuna measured the EPR spectra and susceptibility, and E.J.L.M. performed the EPR simulations. The X-ray structure determinations were performed by R.J.P. and C.A.M.

Corresponding authors

Correspondence to Marco Affronte or Richard E. P. Winpenny.

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Timco, G., Carretta, S., Troiani, F. et al. Engineering the coupling between molecular spin qubits by coordination chemistry. Nature Nanotech 4, 173–178 (2009). https://doi.org/10.1038/nnano.2008.404

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