Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

A photon–photon quantum gate based on Rydberg interactions


The interaction between Rydberg states of neutral atoms is strong and long-range, making it appealing to put it to use in the context of quantum technologies. Recently, first applications of this idea have been reported in the fields of quantum computation1 and quantum simulation2,3,4. Furthermore, electromagnetically induced transparency allows one to map these Rydberg interactions to light5,6,7,8,9,10,11,12,13,14,15. Here we exploit this mapping and the resulting interaction between photons to realize a photon–photon quantum gate16,17, demonstrating the potential of Rydberg systems as a platform also for quantum communication and quantum networking18. We measure a controlled-NOT truth table with a fidelity of 70(8)% and an entangling-gate fidelity of 63.7(4.5)%, both post-selected upon detection of a control and a target photon. The level of control reached here is an encouraging step towards exploring novel many-body states of photons or for future applications in quantum communication and quantum networking18.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Atomic level schemes.
Fig. 2: Simplified scheme of the experimental set-up.
Fig. 3: Performance of the photon-photon gate.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.


  1. Saffman, M. Quantum computing with atomic qubits and Rydberg interactions: progress and challenges. J. Phys. B 49, 202001 (2016).

    Article  ADS  Google Scholar 

  2. Schauß, P. et al. Crystallization in Ising quantum magnets. Science 347, 1455–1458 (2015).

    Article  ADS  Google Scholar 

  3. Labuhn, H. et al. Tunable two-dimensional arrays of single Rydberg atoms for realizing quantum Ising models. Nature 534, 667–670 (2016).

    Article  ADS  Google Scholar 

  4. Bernien, H. et al. Probing many-body dynamics on a 51-atom quantum simulator. Nature 551, 579–584 (2017).

    Article  ADS  Google Scholar 

  5. Lukin, M. D. et al. Dipole blockade and quantum information processing in mesoscopic atomic ensembles. Phys. Rev. Lett. 87, 037901 (2001).

    Article  ADS  Google Scholar 

  6. Friedler, I., Petrosyan, D., Fleischhauer, M. & Kurizki, G. Long-range interactions and entanglement of slow single-photon pulses. Phys. Rev. A 72, 043803 (2005).

    Article  ADS  Google Scholar 

  7. Gorshkov, A. V., Otterbach, J., Fleischhauer, M., Pohl, T. & Lukin, M. D. Photon–photon interactions via Rydberg blockade. Phys. Rev. Lett. 107, 133602 (2011).

    Article  ADS  Google Scholar 

  8. Pritchard, J. D. et al. Cooperative atom–light interaction in a blockaded Rydberg ensemble. Phys. Rev. Lett. 105, 193603 (2010).

    Article  ADS  Google Scholar 

  9. Firstenberg, O. et al. Attractive photons in a quantum nonlinear medium. Nature 502, 71–75 (2013).

    Article  ADS  Google Scholar 

  10. Baur, S., Tiarks, D., Rempe, G. & Dürr, S. Single-photon switch based on Rydberg blockade. Phys. Rev. Lett. 112, 073901 (2014).

    Article  ADS  Google Scholar 

  11. Gorniaczyk, H., Tresp, C., Schmidt, J., Fedder, H. & Hofferberth, S. Single-photon transistor mediated by interstate Rydberg interactions. Phys. Rev. Lett. 113, 053601 (2014).

    Article  ADS  Google Scholar 

  12. Tiarks, D., Baur, S., Schneider, K., Dürr, S. & Rempe, G. Single-photon transistor using a Förster resonance. Phys. Rev. Lett. 113, 053602 (2014).

    Article  ADS  Google Scholar 

  13. Tiarks, D., Schmidt, S., Rempe, G. & Dürr, S. Optical π phase shift created with a single-photon pulse. Sci. Adv. 2, 1600036 (2016).

    Article  ADS  Google Scholar 

  14. Ningyuan, J. et al. Observation and characterization of cavity Rydberg polaritons. Phys. Rev. A 93, 041802 (2016).

    Article  ADS  Google Scholar 

  15. Thompson, J. D. et al. Symmetry-protected collisions between strongly interacting photons. Nature 542, 206–209 (2017).

    Article  ADS  Google Scholar 

  16. O’Brien, J. L., Pryde, G. J., White, A. G., Ralph, T. C. & Branning, D. Demonstration of an all-optical quantum controlled-NOT gate. Nature 426, 264–267 (2003).

    Article  ADS  Google Scholar 

  17. Hacker, B., Welte, S., Rempe, G. & Ritter, S. A photon–photon quantum gate based on a single atom in an optical resonator. Nature 536, 193–196 (2016).

    Article  ADS  Google Scholar 

  18. Kimble, H. J. The quantum internet. Nature 453, 1023–1030 (2008).

    Article  ADS  Google Scholar 

  19. He, B., Sharypov, A. V., Sheng, J., Simon, C. & Xiao, M. Two-photon dynamics in coherent Rydberg atomic ensemble. Phys. Rev. Lett. 112, 133606 (2014).

    Article  ADS  Google Scholar 

  20. Paredes-Barato, D. & Adams, C. S. All-optical quantum information processing using Rydberg gates. Phys. Rev. Lett. 112, 040501 (2014).

    Article  ADS  Google Scholar 

  21. Khazali, M., Heshami, K. & Simon, C. Photon–photon gate via the interaction between two collective Rydberg excitations. Phys. Rev. A 91, 030301 (2015).

    Article  ADS  Google Scholar 

  22. Hao, Y. M. et al. Quantum controlled-phase-flip gate between a flying optical photon and a Rydberg atomic ensemble. Sci. Rep. 5, 10005 (2015).

    Article  ADS  Google Scholar 

  23. Das, S. et al. Photonic controlled-PHASE gates through Rydberg blockade in optical cavities. Phys. Rev. A 93, 040303 (2016).

    Article  ADS  Google Scholar 

  24. Wade, A. C. J., Mattioli, M. & Mølmer, K. Single-atom single-photon coupling facilitated by atomic-ensemble dark-state mechanisms. Phys. Rev. A 94, 053830 (2016).

    Article  ADS  Google Scholar 

  25. Murray, C. R. & Pohl, T. Coherent photon manipulation in interacting atomic ensembles. Phys. Rev. X 7, 031007 (2017).

    Google Scholar 

  26. Lahad, O. & Firstenberg, O. Induced cavities for photonic quantum gates. Phys. Rev. Lett. 119, 113601 (2017).

    Article  ADS  Google Scholar 

  27. Milburn, G. J. Quantum optical Fredkin gate. Phys. Rev. Lett. 62, 2124–2127 (1989).

    Article  ADS  Google Scholar 

  28. Bowdrey, M. D., Oi, D. K. L., Short, A. J., Banaszek, K. & Jones, J. A. Fidelity of single qubit maps. Phys. Lett. A 294, 258–260 (2002).

    Article  ADS  MathSciNet  Google Scholar 

  29. Hsiao, Y.-F. et al. Highly efficient coherent optical memory based on electromagnetically induced transparency. Phys. Rev. Lett. 120, 183602 (2018).

    Article  ADS  Google Scholar 

  30. Kazimierczuk, T., Fröhlich, D., Scheel, S., Stolz, H. & Bayer, M. Giant Rydberg excitons in the copper oxide Cu2O. Nature 514, 343–347 (2014).

    Article  ADS  Google Scholar 

Download references


This work was supported by Deutsche Forschungsgemeinschaft through Nanosystems Initiative Munich.

Author information

Authors and Affiliations



All authors contributed extensively to the work presented here.

Corresponding author

Correspondence to Stephan Dürr.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Information

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Tiarks, D., Schmidt-Eberle, S., Stolz, T. et al. A photon–photon quantum gate based on Rydberg interactions. Nature Phys 15, 124–126 (2019).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing