Researchers: Kirsten Kanneworff, Mio Poortvliet, Thomas Steenbergen

Quantum Key Distribution (QKD) can secure a communication channel, but it can’t “authenticate” it. How can Alice be sure that she is communicating with Bob and not with some impostor? Next to physical meeting and exchange of cryptographic keys, verifying the geographical location of a party is possibly the only useful option. This can be done by Quantum Position Verification (QPV).

By combining principles from (i) special relativity, which limits the speed of information transfer to the speed of light, (ii) quantum information, which provides information security by the no-cloning theorem, and (iii) computer science, in particular complex functions, we aim to realize QPV.

The setup: Two “verifiers” share a secret channel want to confirm the location of a “prover” P. The verifiers send quantum and classical information to the prover, the prover performs a particular task and returns the result, possibly also quantum information, back to the two verifiers. By analyzing the information and the timing, the position of the prover can be verified.

Lorentz Center@Omega, Leiden, from 13 - 17 July 2026

Quantum position verification (QPV) is emerging as a promising way to use quantum communication to establish trust based on location without requiring any pre-shared keys. This is impossible without the use of quantum information, making it a truly new capability of quantum networks. Recent research has both seen experimental advances towards implementing QPV, and deep theoretical connections between QPV protocol analysis and foundational questions in cryptography and physics. This workshop brought together theoretical and experimental researchers, to advance the understanding of QPV implementations, security proofs and potential loopholes, and to explore connections to a variety of fields including relativistic quantum information and spacetime.

We structured the workshop around the three workshop goals (i) QPV protocols and implementations, (ii) QPV and connections to foundational principles, (iii) Deep use case analysis, and in order to achieve these goals, we formed 3 working groups on the first day which will worked on the 3 closely related challenges. This has very successfully engaged all participants in a useful way, and paved the way for future collaborations, joint publications and grant applications. Another essential part of the workshop were the 3 tutorials where everybody had the chance to work on exciting problems around nonlocal quantum computation, but with the key experts sitting next to you - a very nice and useful experience for everybody.

The organiers: Florian Speelman (IvI, UvA, QuSoft, NL), Paola Grosso (IvI, UvA, NL), Wolfgang Löffler (LION, UL, NL), Adrian Kent (Cambridge UK), Alex May (Perimeter Institute, CAN), Eric Chitambar (Illinois, USA)

We show here the first experiment towards fully secure QPV, using single photons demultiplexed from a single quantum dot - cavity single photon source. Our experiment highlights and explores several of the challenges towards implementing QPV in applications.

Quantum Sci. Technol. 10, 045004 (2025), arXiv:2502.04125, zenodo.15851088

Here is a sketch of the experiment: