Course 8 Quantum cryptography: From one to many photons

N. Gisin, N. Brunner

École d'été de physique théorique, D. Estève, J. M. Raimond +2 more

Course 1. Principles of quantum computation, by Isaak Chuang Course 2. Mesoscopic state superpositions and decoherence in quantum optics, by S. Haroche Course 3. Cavity quantum electrodynamics, by M. Brune Course 4. Quantum optical implementation of quantum information processing, by P. Zoller, J.I. Cirac, Luming Duan and J.J. Garcia-Ripoll Course 5. Quantum information processing in ion traps I, by R. Blatt, H. Haffner, C.F. Roos, C. Becher and F. Schmidt-Kaler Course 6. Quantum information processing in ion traps II, by D.J. Wineland Course 7. Quantum cryptography with and without entanglement, by N. Gisin and N. Brunner Course 8. Quantum cryptography: from one to many photons, by Philippe Grangier Course 9. Entangled photons and quantum communication, by M. Aspelmeyer, C. Brukner and A. Zeilinger Course 10. Nuclear magnetic resonance quantum computation, by J.A. Jones Course 11. Introduction to quantum conductors, by D.C. Glattli Course 12. Superconducting qubits, by Michel H. Devoret and John M. Martinis Course 13. Superconducting qubits and the physics of Josephson junctions, by John M. Martinis Course 14. Josephson quantum bits based on a Cooper pair box, by Denis Vion Course 15. Quantum tunnelling of magnetization in molecular nanomagnets, by W. Wernsdorfer Course 16. Prospects for srtong cavity quantum electrodynamics with superconducting cirquits, by S.M. Girvin, R.-S. Huang, A. Blais, A. Wallraff andf R.J. Schoelkopf

Maria Bondani, Valentina De Renzi

Abstract Quantum technologies rely on superposition and entanglement, concepts that challenge classical physics and provide a rich context for teaching. In this paper, we report on a course for high school teachers that focused on quantum cryptography, one of the most mature quantum technologies. The course aims to provide teachers with an innovative approach to introducing quantum physics at the high-school level, showcasing quantum cryptography as a compelling example of how modern technology exploits fundamental principles of quantum theory. The course covers quantum mechanics, light polarization, and the BB84 quantum key distribution protocol through theoretical and experimental sessions by integrating formal and informal approaches exploiting lectures, online simulations (QuVis) and hands-on laboratory activities (using Thorlabs Quantum Cryptography Demonstration Kit). In addition, a card game, originally developed as a public outreach tool, was introduced to interactively perform the BB84 protocol. Feedback from teachers confirmed the feasibility of integrating these concepts into curricula to promote quantum literacy and engagement in secondary education.

André Chailloux

Anthony Leverrier

Samuel J. Lomonaco

Alice and Bob wish to communicate without the archvillainess Eve eavesdropping on their conversation. Alice, decides to take two college courses, one in cryptography, the other in quantum mechanics. During the courses, she discovers she can use what she has just learned to devise a cryptographic communication system that automatically detects whether or not Eve is up to her villainous eavesdropping. Some of the topics discussed are Heisenberg's Uncertainty Principle, the Vernam cipher, the BB84 and B92 cryptographic protocols. The talk ends with a discussion of some of Eve's possible eavesdropping strategies, opaque eavesdropping, translucent eavesdropping, and translucent eavesdropping with entanglement.