The Signal
JPMorgan Researchers Publish QPV Protocol With Loss-Independent State Preparation
A JPMorganChase research paper introduces a quantum position-verification protocol whose verifier’s state preparation is independent of channel loss and revises security analysis for experimental imperfections. The work also describes QPV a
Quantum.world Team · Written with AI · fact-checked ·
“First, we introduce a robust QPV protocol in which the verifier’s state preparation is independent of channel loss, improving reliability in real-world conditions.”
Wen Yu Kon, Ignatius William Primaatmaja, Kaushik Chakraborty and Charles Lim, authors of the paper
A location claim built on quantum communication
JPMorganChase researchers published a protocol on October 31 that aims to make quantum position verification less vulnerable to channel loss, a practical problem for systems that exchange quantum states between separated sites. The paper, in npj Quantum Information, sets out three contributions: a protocol whose verifier’s state preparation does not depend on channel loss, revised security analysis for experimental imperfections, and a framework for addressing assumptions in existing analyses.
Quantum position verification, or QPV, lets multiple verifiers test whether a prover is at a claimed location using quantum communication and physical assumptions. The protocol’s security depends on whether the prover can answer challenges correctly and quickly enough to satisfy the verifiers’ location test. Loss along a communication channel can complicate that test; the authors’ first contribution is intended to make the preparation of the verifier’s state independent of that loss.
Security analysis meets imperfect hardware
The paper also revises existing security-analysis techniques to account for experimental imperfections, according to its abstract. The authors say they identify implicit assumptions in earlier analyses and provide a framework to remove them. The abstract does not specify numerical performance gains or give a measured security bound, so the work should be read as a protocol and security-analysis contribution rather than a reported hardware result.
That distinction matters because QPV has begun moving from theory into laboratory tests. In a separate study published in Nature Physics on September 3, researchers reported a coherent-state experiment in which the two verifiers were separated by 2 kilometres. The prover was positioned between them, approximately 0.98 kilometres from each verifier; the experiment reported position accuracy better than 75 metres. The JPMorganChase paper proposes a different contribution; its abstract does not claim a new experimental demonstration.
From location checks to QKD authentication
The authors also describe an application beyond checking a prover’s location: using QPV to authenticate classical communication in quantum key distribution. QKD systems use quantum communication to establish keys, while classical messages coordinate the exchange; the paper’s abstract identifies authentication of those classical communications as an example application of QPV.
The article’s publication record shows it was received on June 18, 2025, accepted on July 5, 2026, and published on October 31, 2026. Its authors are affiliated with JPMorganChase’s Global Technology Applied Research group. The paper also discloses that Wen Yu Kon, Ignatius William Primaatmaja and Kaushik Chakraborty are co-inventors on a related patent application filed by JPMorganChase on January 2, 2026.
The test is whether the assumptions hold in practice
The paper’s stated target is the gap between security proofs and imperfect experimental conditions: channel loss, implementation errors and assumptions embedded in earlier analyses. Its proposed framework addresses those questions at the protocol and analysis level, while the September experiment offers a separate reference point for what a QPV setup has achieved in hardware. A next comparison will be whether implementations of the new protocol can retain their security guarantees when real channels and devices introduce loss and error.