A couple weeks ago the “Second Annual Conference on Quantum Cryptography”, QCRYPT 2012, took place in the National University of Singapore. The first installment, in 2011 in Zurich, was a lot of fun, and I was greatly looking forward both to the workshop and to visiting Singapore, a city where I spent three of my teenage years.
The QCRYPT conference series attempts to address what seems to me like a formidable challenge: bringing together all communities working on quantum cryptography, from the hardcore theorists dreaming up relativistic bit commitment schemes (invited talk by Adrian Kent on “Quantum cryptography in Minkowski space”) or ruling out psi-epistemic theories (invited talk by Manas Kumar Patra on “Probing the reality of quantum state”), to the most talented experimentalists presenting detailed reports on recent advances (the best student paper award went to Paul Jouquet for his paper “Experimental demonstration of continuous-variable quantum key distribution over 80 km of standard telecom fiber”).
As you can imagine, such a diverse program makes for quite a diverse crowd, and a clear highlight of the conference is the discussions that take place in the hallways…or on the beach! We had our conference dinner on the Sentosa island (right next to the QIP 2011 rump session, for those who were around), timed to perfection with a beautiful sunset on the impressive Singapore harbor (photos courtesy of the qcrypt website)
Following the excellent food and dreadful beer (they can’t help it — it’s Singapore), the “cerise sur le gateau” came as an impromptu Skype session with, guess whom, the father of quantum cryptography, Stephen Wiesner. Stephanie Wehner had been trying very hard to get him to come, but Wiesner wouldn’t commit. Up till the last minute there was no guarantee we’d hear from him, and in fact he made quite a suspenseful appearance: apparently he had some kind of a private (unconditionally secure?) connection with Charlie Bennett, who was attending the dinner, and Charlie was sharing with us the minute details of Wiesner getting on the bus, off the bus, booting his computer…until it actually happened!
The sound quality wasn’t too good, and video was off, so we didn’t hear that much of him. Wiesner sounded quite curious and entertained though, and he recalled how the first thoughts of his famous quantum money scheme came to him: watching some physics experiment (ran, I think, by the army), he started wondering how quantum particles could be used to transmit information more efficiently. He got the idea of “multiplexing” two different signals in a quantum superposition — of course, while the superposition could in principle carry twice as much information, only one of the two signals, at random, could be recovered! This then somehow led him to the idea of a quantum bank note: a state that can be verified, but not copied (the subject of quantum money is a story for another day…)
At the end of the conversation Wiesner asked the audience if we had any questions. Since no one stood up, he took it upon him to warm up the atmosphere: sounding playful, he asked us what applications we had in mind for quantum key distribution (or was it quantum cryptography?). Silence…no one had any good answer? Indeed, that particular question was a recurrent theme during the whole workshop — maybe I will talk about it a later day; I also hope to discuss the scientific content of the conference some more.
Next year’s QCRYPT will be hosted by IQC Waterloo. The QCRYPT logo is a benevolent-looking sheep, and organizers seems to be putting increasing amounts of effort into promoting it…an attempt at making quantum cryptography less intimidating? To the right is this year’s sheep, the subject of a hotly contested photo contest (see the qcrypt webpage for pictures).
I don’t know about you, but to me this guy really looks like he’s up to something… Next year’s organizers already promised they’ll have a real flesh-and-blood sheep in attendance; we’ll have to see if it looks any more trustworthy.