Probing interacting two-level systems with rare-earth ions

Physical review. B./Physical review. B, vol. 101

Abstract

Two-level systems (TLS) in amorphous materials limit coherence times of a number of solid-state quantum devices. Interactions between TLS become prominent below 100 mK, but the coupling mechanism and statistical properties are still unclear. Here we determine the homogeneous linewidth of ytterbium ions $({\mathrm{Yb}}^{3+})$ in silica glass at 10--80 mK by using photon echo techniques as a probe of TLS. First, the homogeneous linewidth can be reduced by applying a magnetic field of 0.3 T. This effect is due to reduced magnetic interactions between adjacent ${\mathrm{Yb}}^{3+}$. Secondly, we observe saturation of the linewidth below 50 mK to a level of approximately 30 kHz, which is much larger than the lifetime-limited value of 0.2 kHz. This saturation behavior is in conflict with the coupling to independent TLS. We show that this effect can be explained by coherently coupled TLS.

Authors 11

1. Dapeng Ding Aachen Huygens-Kamerlingh Onnes Laboratory

   Leiden University

   Affiliation as printed

   Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands

2. David van Driel Aachen Huygens-Kamerlingh Onnes Laboratory

   Leiden University

   Affiliation as printed

   Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands

3. L. M. C. Pereira

   KU Leuven

   Affiliation as printed

   KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium

4. Jared F. Bauters

   University of California, Santa Barbara

   Affiliation as printed

   Department of Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara, California 93106, USA

5. Martijn J. R. Heck

   University of California, Santa Barbara

   Affiliation as printed

   Department of Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara, California 93106, USA

6. G. Welker Aachen Huygens-Kamerlingh Onnes Laboratory

   Leiden University

   Affiliation as printed

   Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands

7. M. J. A. de Dood Aachen Huygens-Kamerlingh Onnes Laboratory

   Leiden University

   Affiliation as printed

   Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands

8. A. Vantomme

   KU Leuven

   Affiliation as printed

   KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium

9. John Edward Bowers

   University of California, Santa Barbara

   Affiliation as printed

   Department of Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara, California 93106, USA

10. W. Löffler Aachen Huygens-Kamerlingh Onnes Laboratory

    Leiden University

    Affiliation as printed

    Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands

11. Dirk Bouwmeester Aachen Huygens-Kamerlingh Onnes Laboratory

    Leiden University · University of California, Santa Barbara

    Affiliation as printed

    Department of Physics, University of California Santa Barbara, Santa Barbara, California 93106, USA

    Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands