QIP 2010 – Further thoughts and CAKE!

So I’m back from QIP now, and full of chocolate. One might say I am maximally satisfied. However I didn’t have time to post this final update so I’ll do it now.

I really enjoyed 2 talks on Thursday afternoon session. The first was by Roderich Moessner and the second by Julia Kempe. They were entitled:

“Random quantum satisfiability: statistical mechanics of disordered quantum optimization” and “A quantum Lovasz Local Lemma” respectively.

I enjoyed these talks because they weren’t completely theoretically based, even though the titles made them sound like they might have been. In particular, I liked the way that random, average and typical instances were considered.

The bounds of ‘hardness’ (going from always satisfiable (easy) to possibly satisfiable (hard) to unsatisfiable (easy)) as you increase the number of clauses compared to the number of variables in a SAT problem were explored, and what kind of phase transitions occur throughout this process. Entanglement can help make some of the possibly satisfiable ones easier, so effectively utilising quantum mechanics allows you to tighten the boundaries of the ‘region of hardness’.

One final thought that I had about the conference was that I think that QIP people need to think about Physics a bit more. Physics seems to underlie all these processes and ties them to the real world in some way. I found that quite a few people were advocating the point of view that Computer Science underlies Physics, but I believe this to be the wrong way of looking at the problem. Physics is all we are given really, it is fruitful to remember this and perhaps just considering it once in a while might help keep you a little more grounded in reality.

Anyway, enough Physics, lets talk about cake. So I mentioned in a previous post about this cake shop I found in Zurich called Cakefriends. Well now I have pictures.

The cake that I chose was a heterostructure of deliciously thick cream (almost cheesecake thick) with interstitial poppy seed sponge layers. To complete the unit cell there was some raspberry sauce around the outside of each sponge layers. It was served in a glass:

Here is a picture of me enjoying said cake. And yes, there were Physics discussions throughout the cakey experience, which should always be the case.

And a photo from the Cakefriends menu:

Yes. Yes we do.

Also thanks to this conference I finally understand the meaning of the complexity class qpoly. Thanks QIP for clearing this one up for me.

QIP 2010 – Day 2, erm I mean 3

I’ve been so busy at this conference, I haven’t had much time to write stuff down. So yes, I totally suck at liveblogging 🙂

On Tuesday the sessions seemed a lot more attuned to the underground QIP physics community. You wouldn’t know we existed by just looking, but we’ve been able to signal our presence to each other by arranging the croissants into Ising configurations.

Anyway, I very much enjoyed the talks by Hari Krovi and Phillipe Corboz. Hari talked about the failure of the Adiabatic algorithm for certain problem instances. This is a very open question and sparked much discussion. My take on this is that most real world problems do not seem to fall into this category, they tend to be somewhat easier. Concentrating on the very hardest instances is useful from a theoretical point of view but not really from a real world applications one.

Kristan Temme’s talk about quantum metropolis sampling was also very interesting. I find myself trying to relate every talk I hear to the adiabatic algorithm. It’s pretty tricky as most of the topics first assume a Universal gate model Quantum Computer, with an extreme amount of error correction. But as I’m interested in actually building Quantum Computers, and I believe that AQC is the best way to achieve this currently, I’m looking for ways to manipulate all these results into a more limited, but realizable framework.

I’m also even posting *this* a day late because just as I was about to make the entry public my internet allocation ran out….

QIP 2010 – Day 1

Hmmm. I think I AM the only experimental physicist here 🙂

Still, I’ve absorbed a fair amount. Interestingly quite a few of the conference participants seem to be Theoretical Computer Scientists with only very slight inclinations towards the quantum, although I haven’t sampled a large set of conversations yet.

I had lunch with Ed Farhi and several other people working in the area of AQO/AQC. it was really interesting to discuss some of the open questions regarding the adiabatic quantum algorithm.

I really enjoyed Daniel Gottesman’s (Perimeter Institute) talk as he discussed SAT problems in spin systems, which are things that we can actually make and play with, and see if they are behaving quantum mechanically, so I’ll have to talk to people a bit more about that. I’m not sure if there’s any way to distinguish between extremely similar complexity classes such as ‘QMA’ and ‘QMAEXP’ experimentally using such systems, but it might be something worth thinking about.

I also finally met Quantum Moxie.

I really like the way that they have put chocolate bars on all the seats in the lecture theatre…

Anyway, more later.

QIP2010 – Preconference musings

I’m now in Zurich at the QIP2010 conference. I’m hoping to do a bit of live-blogging! I’ve never live-blogged from a conference before, so we’ll see how this goes.

I’m looking forward to hearing all about the cutting edge of theoretical quantum information! I’ll probably be the only experimentalist there and be totally confused…

Zurich seems very beautiful, I love the river running through the city and there are several buildings with really spikey spires. (A red one and a green one). If I had any sense of culture or history I would tell you all about these buildings. But at the moment I just think they are cool because they are spikey. Pictures and slightly more useful information may follow soon.

There is also a cake shop. It’s called CakeFriends. It’s like they knew I was coming. I tried to get in there today but it was way too busy. Looks like they do really cool coffee and cake 😀 Gaining access to this confectionary resource is definitely on the agenda for the upcoming week!

Writing a cool lecture is hard. But rewarding!

I’m currently writing a lecture about…well I’m not quite sure what it is going to be about yet. It’s an IOP evening lecture, and I want it to be awesome.

It’s entitled: Quantum Computing – The end of the silicon chip?
For a start that’s a misnomer as Quantum Computing devices are still, for the most part, made on Silicon chips 🙂 But the idea is that there is a materials revolution in there as well as a shift in computational paradigm.

I want to do a slightly unusual style of lecture where I talk about lots of really cool stuff. I want to get some brains in there somehow so I’m going to talk about the applications of QCs to neural networks. I also want to get in there the idea of how you actually make integrated circuits, what is actually INSIDE your iPhone, and just how awesome the engineering that goes on to produce that kind of thing is. I have a hunch that there’s nothing on the National Curriculum about that kind of stuff. (There certainly wasn’t when I was taught at school). I also want to get some LN2 demos in there as schools always love this kind of stuff.

I’m actually not a great fan of the current demo that I routinely give to audiences of varying sizes. The format generally goes like: Low temp Physics -> Superconductivity -> JJ/SQUIDs -> Quantum Computing.

Why is this bad?

Well, one problem I find with this style of lecture is that you get onto the cool stuff (from my POV) at the end (hell, we make stuff colder than interstellar space and then make it quantum compute. We exploit the power of the multiverse, b*tches!) but in order to get to that bit you have to explain superconductivity, and in order to explain that you first have to talk about lots of low temperature experiments and properties of solids, liquids and gases, blah blah. So what actually happens is that you do all the LN2 demos at the start, and then the audience gets really bored at the end. I also just don’t think that superconductors have the same WOW factor that they used to. I give this lecture so many times and talking about things like High Temperature Superconductivity being cutting edge research just doesn’t do it for schoolkids anymore (it’s also not true). And they’ve all seen the floating magnet and the liquid nitrogen before. It’s sometimes embarrassing…

The second problem is that the EMPHASIS is all wrong. You shouldn’t try to entice kids into Physics by throwing liquid Nitrogen at them, putting balloons and flowers and bananas and *insert your favourite normally-at-room-temperature item here* into cryogenic liquids. It’s quite fun for them to watch at the time, but it’s actually quite psychologically deceitful. Believe it or not, physicists don’t actually dip bananas into cryogens as part of their normal working day.

In fact what we do is even cooler, and getting across a sense of why is much more difficult. But it is also a much more rewarding challenge. So…what I shall try to do is either play down the easy-but-somewhat-irrelevant demos, make the later stuff more awesome, or intersperse the demos through the talk somehow. I suspect I will implement a combination of the latter two.

I also think that these kind of lectures are not supposed to teach kids what we already know about Physics. We should teach them that there’s a lot we don’t know. That is what will probably make them want to be scientists in the future. So explaining the ideal gas law is all very well and good, but they can do that in class. By holding these research lectures, we should inspire and humbly explain that as a scientific community we really don’t know enough, but it’s a great challenge to face that unknown. To teach them that this is where we are stuck, and that’s why we need people like you guys sitting in the audience to ace your science classes now, and help us out in the future.

I’m probably going to blog about the progress of this as I write it. Hey, I might even get some more people attending! I’m thinking of doing a RI Christmas lecture style thing with lots of visuals, demos, audience participation, microscope connected to projector. etc. I’m going to try to get a volunteer to dress up in a cleanroom suit and bring him/her into the lecture theatre to illustrate the idea of humans+fab=bad…any takers? 😀

Another amazing video

Another stunningly beautiful video visually describing our place in the universe.

The bit that struck me the most was how small our sphere of entire radio wave transmission is, compared to the size of the galaxy. Pretty obvious when you think about it but putting it into this visualisation really helps to grasp the sense of scale.

I love the mapping of all the earth’s satellites too.