Having been under the weather and also inundated with family over the past week and a half I have not had a chance to put up some thoughts about the March Meeting talks until now. And, actually, I’m only going to summarize two at the moment that particularly interested me. I’ll summarize some more in the days to come, but I’ll start with these two.
Personally, I’ve always been particularly interested in the work the Vienna group is doing in the Canary Islands. This year they reported on progress with their 144 km relay in which they achieved a half-millisecond lifetime for the Bell state (the longest on record). The link attenuation, while better than weakly coherent transmission, is still pretty darn low. Nonetheless, these guys from Vienna are always pushing the envelope. I would love to spend some time working with them on something (Caslav Brukner has helped critique a paper of mine before, but I’d love to get into some of the experimental stuff as well).
In a somewhat related problem (i.e. the lifetime of the entangled Bell states), there was some progress reported by Zhen-Sheng Yuan on quantum memory in which a quantum repeater is used. So, not only is decoherence a problem for the distance of information transmission, it is also a problem for storing the information for long periods of time (as we saw above, 0.5 ms is considered long). So Yuan’s group employed these repeaters and essentially entangled photons with atoms which is essentially a swap of information between two different types of storage “device,” so-to-speak. The photonic states, then, get stored in atomic states which have a longer lifetime. Not only does this improve the lifetime and efficiency, it also improves the scalability issue for quantum computers.
I found these two particularly interesting because they represent significant progress towards practical quantum communication and computing. This is truly exciting stuff!