John G. Rarity FRS[1] is professor of optical communication systems in the department of electrical and electronic engineering at the University of Bristol, a post he has held since 1 January 2003.[2] He is an international expert on quantum optics, quantum cryptography and quantum communication using single photons and entanglement. Rarity is a member of the Quantum Computation and Information group and quantum photonics at the University of Bristol.[3][4]

John Rarity
John Rarity at the Royal Society admissions day in London, 2015
John G. Rarity
Alma materUniversity of Sheffield (BSc)
Royal Military College of Science (PhD)
Scientific career
InstitutionsUniversity of Bristol
ThesisNumber fluctuation spectroscopy applied to coagulating dispersions (1984)



Rarity was educated at the University of Sheffield (BSc)[5] and awarded a PhD from the Royal Military College of Science in 1984 for research on spectroscopy applied to coagulating dispersions.[6]

Research and career


Prior to moving to the University of Bristol in 2001, Rarity worked as a physicist at the Defence Evaluation and Research Agency (DERA) arm of the Ministry of Defence (United Kingdom).

Notable early achievements while at DERA included demonstrations of quantum interference and non-locality over large distances, demonstrating a violation of Bell's Inequality over 4 km of optical fibre in 1994. These experiments were followed by work in quantum cryptography, resulting in his team at DERA setting a world record of 1.9 km range for free space secure quantum cryptography.[7] A collaboration with Ludwig-Maximilian University, Munich in 2002 successfully demonstrated an open air quantum cryptography experiment over a distance of 23.4 km.

Since moving to the University of Bristol, Rarity has built up a group working in experimental quantum optics. One project which has received substantial publicity recently in collaboration with the Quantum Information Processing group at HP Labs is developing affordable quantum key distribution systems.[8] The scheme reduces the cost by using pulsed LEDs rather than lasers as the source of transmitted qubits.[9]

In 2007 Rarity collaborated in a demonstration of quantum key distribution using free space optical communications over 144 km[10] between the islands of Tenerife and La Palma.



His books include Microcavities and Photonic Bandgaps: Physics and Applications[11] and highly cited papers include Practical quantum cryptography based on two-photon interferometry[12] and Experimental violation of Bell's inequality based on phase and momentum.[13]

Awards and honours


Rarity won the Thomas Young Medal and Prize in 1995.

Rarity was elected a Fellow of the Royal Society (FRS) in 2015.[1]


  1. ^ a b Anon (2015). "Professor John Rarity FRS – The Royal Society". Retrieved 1 May 2015. One or more of the preceding sentences incorporates text from the website where:

    “All text published under the heading 'Biography' on Fellow profile pages is available under Creative Commons Attribution 4.0 International License.” --Royal Society Terms, conditions and policies at the Wayback Machine (archived 2016-11-11)

  2. ^ "University News – New chairs" (PDF). University of Bristol. April 2003. p. 9. Archived from the original (PDF) on 28 June 2006. Retrieved 25 July 2006.
  3. ^ "Bristol University Physics—Centre for Quantum Photonics—Academic Staff". University of Bristol. Archived from the original on 8 February 2010. Retrieved 29 May 2010.
  4. ^ John Rarity publications indexed by Google Scholar  
  5. ^ Bristol, University of. "Professor John Rarity - Faculty of Engineering".
  6. ^ Rarity, John G. (1984). Number fluctuation spectroscopy applied to coagulating dispersions (PhD thesis). Royal Military College of Science. OCLC 499808067. EThOS
  7. ^ "DERA Scientists achieve world record 1.9 km range for free-space secure key exchange using quantum cryptography". (Press release). DERA. January 2001. Archived from the original on 28 September 2006. Retrieved 25 July 2006.
  8. ^ "'Quantum ATM' rules out fraudulent web purchases". {{cite journal}}: Cite journal requires |journal= (help)
  9. ^ J. L. Duligall; M. S. Godfrey; K. A. Harrison; W. J. Munro; J. G. Rarity (2006). "Low Cost and Compact Quantum Cryptography". New Journal of Physics. 8 (10): 249. arXiv:quant-ph/0608213. doi:10.1088/1367-2630/8/10/249.
  10. ^ R. Ursin; F. Tiefenbacher; T. Schmitt-Manderbach; H. Weier; T. Scheidl; M. Lindenthal; B. Blauensteiner; T. Jennewein; J. Perdigues; P. Trojek; B. Ömer; M. Fürst; M. Meyenburg; J. Rarity; Z. Sodnik; C. Barbieri; H. Weinfurter; A. Zeilinger (2007). "Entanglement-based quantum communication over 144 km". Nature Physics. 3 (7): 481. arXiv:quant-ph/0607182. Bibcode:2007NatPh...3..481U. doi:10.1038/nphys629. Nature Physics 3, 481 – 486.
  11. ^ NATO Scientific Affairs Division (1996). C. Cargese; C. Weisbuch and John Rarity (eds.). Microcavities and Photonic Bandgaps: Physics and Applications. Springer. ISBN 0-7923-4170-8. OCLC 35055551.
  12. ^ Artur K. Ekert; John G. Rarity; Paul R. Tapster; G. Massimo Palma (1992). "Practical quantum cryptography based on two-photon interferometry". Physical Review Letters. 69 (9): 1293–1295. Bibcode:1992PhRvL..69.1293E. doi:10.1103/PhysRevLett.69.1293. PMID 10047180.
  13. ^ J. G. Rarity; P. R. Tapster (1990). "Experimental violation of Bell's inequality based on phase and momentum". Physical Review Letters. 64 (21): 2495–2498. Bibcode:1990PhRvL..64.2495R. doi:10.1103/PhysRevLett.64.2495. PMID 10041727.