QCMC 2014

I am back after a week in Hefei, China, were I was attending the 12th International Conference on Quantum Communication, Measurement and Computing (QCMC). This is probably my favourite conference because it attracts researchers from the entire quantum information community: theorists, experimentalists, computers scientists and engineers. It is also a great way of catching up with the results of the field in the past two years, specially given that many of the talks are informative rather than technical.

On this occasion, the venue was the Institute for Advanced Technology, which is part of the University of Science and Technology of China. The building is impressive in size, dwarfing the dimensions of IQC’s headquarters: the Mike and Ophelia Lazaridis Quantum-Nano Centre. However, perhaps owing to its enormity, it is eerily empty, with most of its floors unoccupied. I venture to speculate that the institute, as well as its surrounding infrastructure, was planned as a long-term investment, and it will take time to have all the facilities running at full capacity. China has grown at a formidable rate in recent decades, and it seems that it is not stopping any time soon. I am genuinely excited and curious to see what this very peculiar and intriguing country will be like in the future.

Since the conference venue was in an unoccupied part of the city which is very hard to access, the organizers had planned for a collection of shuttle buses to take the attendees back and forth from the spectacular Jingling Grand Hotel to the institute. Breakfast and dinner were provided at the hotel, and the evening events were all happening in there as well, which made it basically mandatory for everyone to stay in the hotel. This situation gave the whole conference a very strange ‘school-trip’ feel to it: wake up, have breakfast, take the bus, attend talks, have lunch in the cafeteria, attend more talks, go back in the bus, have dinner, repeat. I disliked this greatly.

Institute for Advanced Technology

Institute for Advanced Technology

QCMC is not a technical, highly specialized conference, but instead it is closer to a summary of the results of the field. As such, close to half of the talks were ‘invited talks’, given by well-known PIs who were selected by the conference committee to talk about the research in their groups. Most of the talks were thus simply an overview of the activities that are taking place in several groups around the world. Overall, I enjoyed the majority of the talks and learnt significantly from them.

I can’t really comment on all the talks, so I have selected my favourite five instead. Note that this is a highly biased selection, as I tend to favour talks that are closest to my research interests.

Eugene Polzik: Beyond the Heisenberg uncertainty. I loved this talk because it introduced me to an entire field I was completely unaware of. This guy and his team are studying — read this carefully — the trajectory of oscillating systems with a negative mass in a quantized reference frame which is entangled with the oscillator. Extremely interesting stuff, with practical applications to magnetometry.

Stephanie Wehner: Quantum cryptography beyond QKD: As I become increasingly interested in quantum cryptography, it is very helpful to hear someone carefully articulate recent advances in the field and new research directions. This talk also convinced me of the power of moving away from information-theoretic security and instead opting for a framework to bounding the quantum capabilities of adversaries.

Nathan Killoran: Identical particles: an accessible source of entanglement: I admit I have a weak spot for elegant, simple and yet profound results. To understand Nathan’s result one needs only to read the title of his talk and carry out a simple calculation, and yet the result is enlightening and apparently settles a long-standing debate on the significance of entanglement in systems of identical particles.

Quantum cryptography using practical photonic systems, Eleni Diamanti: A very helpful overview of current research in quantum cryptography. It was very useful to hear the status, advantages, and disadvantages of continuous-variable QKD being stated clearly and eloquently. It also made me very curious about the challenges of improving quantum coin-flipping protocols and of performing cryptographic tasks in integrated photonic systems.

Steering many-body quantum dynamics, Tommaso Calarco: This has to be the best conference talk I have ever seen. It had it all: comedy, intrigue, theatrics, animations, eloquence and good science. Kudos to Tommaso for showing the rest of us how it’s done.

Unfortunately, the poster session was quite disappointing. The talks in the morning took longer than planned (more on this later), and this led to less time allocated for the poster session. Moreover, we were not given materials to hang the posters, so most of us had to rely on other people who had brought tape or blu-tack. Since there were so many posters and such little time, I had no chance to actually take a look at other posters, but spend the session presenting mine. I was fortunate to have many people interested in my results, and I managed to have very fruitful discussion with several researchers.

Pretending to discuss our posters with Jean-Daniel Bancal. Photo courtesy of Valerio Scarani.

Pretending to discuss our posters with Jean-Daniel Bancal. Photo courtesy of Valerio Scarani.

The conference started on a Sunday — I’m still not sure why — and on Monday night, in the hotel, there was an extremely interesting series of lectures given by the editors of PRL and Nature, discussing general aspects of the editorial process, problems with journal metrics and guidelines for submissions. The issues and polemics surrounding scientific publishing, specially with prestigious journals such as PRL and Nature, are close to the heart (brain?) of any scientist, so this session was obviously going to generate some reactions. Before I comment on this further, let me say that I find that the editors of these journals are actually doing a great job, and that most of the problems are not attributable to them but to the entire scientific community, as well as granting agencies and selection committees.

In case you were wondering how to write a PRL.

In case you were wondering.

Of course, I wasn’t the only one with an opinion on the matter. The day after, Reinhard Werner, during his award talk, took the opportunity to state his view. He planned to do so as a bonus to his talk on uncertainty relations, but it really was the thing to remember about his presentation. To give you an idea, one of the questions from the audience, after he finished his talk when he run out of time to continue was: “This is a question for the chairman: Can we give Prof. Werner extra time to continue talking about scientific publishing?”. The crowd applauded loudly and so the talk went on, beyond the schedule. Hence the shorter poster session.

Werner’s main point, which many of us are well aware of, is that the incessant focus on the impact factor — which Robert Garisto cleverly pointed out most scientists can’t even define — is extremely detrimental to science. In his words, “when we are judged by idiotic criteria, we all waste a lot of time behaving like idiots.” Carl Caves recently wrote a very timely and accurate column on making essentially this same point, which I highly recommend.

I want to dwell further on Werner’s talk. His first point was that judging the quality of a paper based on number of citations and journal of appearance is simply flawed. I already wrote an entire blog post about it more than a year ago.


Science is not just a competitive sport.

He went on to illustrate this further by pointing out that none of what he considers to be his best 10 papers are PRLs, and neither are any of the papers for which he was receiving the award. Nicolas Gisin also explained in his subsequent talk that his best paper was actually rejected by PRL and appeared instead in an obscure swiss journal. Werner also pointed out something we all know but are very good at forgetting: citation statistics are not an adequate method of assessing the quality of a paper.


Why do YOU cite papers?

Overall, Reinhard Werner made a great service to the quantum information community by reminding us that cleverness to solve scientific problems doesn’t give us a free license to behave like imbeciles.

The talk that followed was the other award talk by Nicolas Gisin. It was inspiring to see him literally share his award with all the students and postdocs that had contributed to his research career. Something else worth remembering: science is collaborative and highly social.


I want to add that this conference left me wondering about the future of the field. I am still fairly new to research, but I didn’t really see much novelty and certainly no breakthroughs, at least not compared to what I saw during QCMC 2012. The field has matured significantly and any ground-breaking results will not be easy to predict nor to attain. Maybe I am making a good bet by looking for new protocols in quantum communication? I guess we’ll have to wait for QCMC 2106 in Singapore!

Hefei skyline.

Hefei skyline.



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