P13 - Photonic Quantum Computing

Philip Walther


Single photons provide unique advantages for quantum information applications due to their robustness, individual addressability and bosonic character. Moreover, the intrinsic mobility of single photons makes them the best quantum information carriers for quantum networks, delegated quantum cloud computing [R13-1] and novel quantum computation schemes such as Boson Sampling and quantum random walks [R13-2].

The long-term goals of our project are the development of quantum photonics technology for (i) secure delegated quantum computing in real-life scenarios and quantum homomorphic encryption schemes that enable a broad class of quantum computation on encrypted data, and (ii) hybrid quantum-classical systems, where classical computation is supported by feasible quantum photonics technology, and (iii) implementing machine learning and random-walk computations using complex integrated network structures, and (iv) demonstrating novel quantum protocols that exploit superimposed orders of gates for outperforming standard, fixed-order schemes.

PI Philip Walther on
Photonic Quantum Computing


Subproject Leader: Philip Walther

Co-PIs: Lee Rozema, Michael Trupke

PhD Students: Céline Van Valkenhoef, Valeria Saggio, Guilherme Luiz Zanin, Michael Antesberger


Experimental quantum speed-up in reinforcement learning agents
V. Saggio, B.E. Asenbeck, A. Hamann, T. Strömberg, P. Schiansky, V. Dunjko, N. Friis, N.C. Harris, M. Hochberg, D. Englund, S. Wölk, H. J. Briegel, P. Walther ,
Nature 591, 229–233 (2021)

Experimental quantum communication enhancement by superposing trajectories
G. Rubino, L. A. Rozema, D. Ebler, H. Kristjánsson, S. Salek, P. A. Guérin, A. A. Abbott, C. Branciard, Č. Brukner, G. Chiribella, P. Walther
Phys. Rev. Research 3, 013093 (2021)

Experimental Quantum Homomorphic Encryption
J. Zeuner,I. Pitsios, SH. Tan, A. Sharma, J. Fizsimons, R. Osellame and P. Walther.
npj Quantum Information 7, 25 (2021)

Quantum computing with graphene plasmons
I. A. Calafell, J. D. Cox, M. Radonjic, J. R. M. Saavedra, F. J. Garcia de Abajo, L. A. Rozema, P. Walther
npj Quantum Information, 5, 37 (2019)

Experimental few-copy multipartite entanglement detection
V. Saggio, A. Dimić, C. Greganti, L. A. Rozema, P. Walther, B. Dakić
Nature Physics 15 (2019)

Experimental Two‐Way Communication with One Photon
F. Massa, A. Moqanaki, Ä. Baumeler, F. Del Santo, J. A. Kettlewell, B. Dakić, P. Walther,
Advanced Quantum Technologies (2019).

Trace-free counterfactual communication with a nanophotonic processor
I. Alonso Calafell, T. Strömberg, D. R. M. Arvidsson-Shukur, L. A. Rozema, V. Saggio, C. Greganti, N. C. Harris, M. Prabhu, J. Carolan, M. Hochberg, T. Baehr-Jones, D. Englund, C. H. W. Barnes, P. Walther,
npj Quantum Information 5, 61 (2019).

For further publications: see here.