[Joint CQSE & NCTS Seminar] Device-Independent Quantum Rigidity for Secure Global Positioning

Title: [Joint CQSE & NCTS Seminar] Device-Independent Quantum Rigidity for Secure Global Positioning
Speaker: Prof. En-Jui Kuo (National Yang Ming Chiao Tung University)
Time: 2026/5/22 (Fri.) 14:30-15:30
Place: NCTS Physics Lecture Hall, 4F, Chee-Chun Leung Cosmology Hall, NTU
Online: https://nationaltaiwanuniversity-zbh.my.webex.com/nationaltaiwanuniversity-zbh.my/j.php?MTID=madb2c3b9d23a56faace3593823ecfdee
 

Abstract
Device-independent (DI) protocols provide the strongest form of security by eliminating trust assumptions on quantum devices and relying solely on observed nonlocal correlations together with quantum rigidity. In this talk, I will discuss how multipartite Bell nonlocality and self-testing can be leveraged to secure distributed positioning tasks, using a quantum-secured global positioning system (GPS) as a concrete case study.

We consider a protocol based on a five-qubit entangled state shared among four satellites and one ground station, where correct state preparation and measurement behavior are certified solely through Bell inequality violations. I will explain how rigidity guarantees enable device-independent authentication against spoofing and cyberattacks, and discuss practical considerations in the NISQ era, including implementation trade-offs between superconducting and trapped-ion platforms, as well as constraints arising from long-distance photonic distribution.

The emphasis of this talk will be on conveying the core ideas of device independence and self-testing, while providing sufficient background to make the discussion accessible to a broad quantum information audience.

For reference, my related paper is available here:
https://link.springer.com/article/10.1140/epjqt/s40507-026-00470-6
 
Biography
En-Jui Kuo

Education
University of Maryland, College Park Aug. 2018 – Aug. 2023
Ph.D. in Physics
• Awarded the Monroe H. Martin Graduate Research Fellowship (2023).
• Researched quantum computing, information theory, and complexity.
• Studied condensed matter physics and applied machine learning.

National Taiwan University, Taipei Feb. 2016 – Jul. 2017
M.Sc. in Physics, GPA: 3.97
• Conducted research in string theory.

National Yang Ming Chiao Tung University, Hsinchu Sep. 2012 – Jan. 2016
B.Sc. in Electrophysics, GPA: 3.98
• Graduated in 3.5 years with academic honors.
• Early research experience in high energy physics.

Academic Appointments
National Yang Ming Chiao Tung University, Hsinchu Feb. 2025 – Present
Assistant Professor, Department of Electrophysics

National Center for Theoretical Sciences (NCTS) Jan. 2024 – Jan. 2025
Postdoctoral Researcher, Quantum Information Group
• Collaborated on quantum information and complexity theory.
• Explored machine learning techniques in quantum systems.

Foxconn Technology Group (Hon Hai Research Institute) Sep. 2022 – Dec. 2023
Intern, Quantum Research (Remote)
• Studied quantum algorithms using matrix completion techniques.
• Contributed to quantum oracle separation problems.

Selected Publications
Quantum Information, Computing, and Simulation
• Quantum state tomography via non-convex Riemannian gradient descent, Phys. Rev. Lett. 132, 240804
(2024).
• Qubit-oscillator concatenated codes: decoding formalism and comparison, PRX Quantum 4, 020342.
• Efficient quantum computations of molecular properties using wavelet orbitals, PRX Quantum 3, 020360.
• Boson sampling for generalized bosons, Phys. Rev. Research 4, 043096.
Machine Learning in Condensed Matter
• Unsupervised learning of SPT phase transitions, Phys. Rev. B 105, 235136.
• Decoding CFTs: from supervised to unsupervised learning, Phys. Rev. Research 4, 043031.
• Learning molecular dynamics with LSTM networks, Nat. Commun. 11, 1–11.

Research Areas and Skills
Languages: Python, Julia
Research Areas: Quantum Computing, Quantum Information, Complexity Theory, Condensed Matter,
Mathematical Physics