Hot Topics and Controversies

The Dave Bacon post linked earlier today is actually the beginning of a plug for Doug Natelson’s list of hot topics and controversies in condensed matter and nanoscale science.

As was suggested in a recent comment, now that a nonzero number of condensed matter and nano people are (apparently) reading this blog (at least occasionally), this could be a fun opportunity to have a series of discussions about the hot topics and controversies out there in the world of condensed matter and nanoscale science. The idea would be to take maybe one topic a week, give a relatively gentle introduction to the subject, and then have some discussion, just for fun. This only works, of course, if enough people contribute to make the discussion interesting, rather than just me pontificating (though I suppose that would be de rigour for a blog). As a preamble, I suggest trying to generate a list of topics.

He follows with a list of 13 big open questions in the field, and it’s a fascinating list of stuff.

It’s a nice idea for a blog series, and it’ll be interesting to see how it works out. Like Dave, I’m tempted to steal it, but there are two problems (discussed after the cut):

The first problem is a bit of a conflict with what I perceive as my audience, and my purpose in writing this blog. I know I have a handful of readers who are in AMO physics, but I think a large fraction of the readership here is non-technical people. And from the beginning of this blog (four years ago– yikes!), I’ve tried to keep the physics discussion accessible to a non-technical audience– no equations requiring LaTeX, no dropping terms like “spontaneous symmetry breaking” in without defining them, a minimal amount of jargon. It’d be a little tough to run a discussion of hot topics and controversies without it sliding into the kind of highly technical material that make many of the blogs on Mixed States all but unreadable to non-specialists. And I’m not entirely comfortable going there.

The other issue is more a matter of the somewhat amorphous nature of modern Atomic, Molecular, and Optical (AMO) physics. I can draw up at least the beginnings of a list of “hot topics” in the field, but the interesting thing about that list is the degree to which they overlap with other disciplines.

For example, there’s been a lot of work done recently on the “crossover region” between the well-described limits of Bose-Eisntein Condensation (BEC) and Bardeen-Cooper-Schrieffer (BCS) pairing of fermions, using quantum-degenerate fermionic atoms with tunable interactions. This is really a problem from condensed matter physics (BCS theory explains one type of superconductivity), being explored in an atomic physics system.

Another subject that turns up a lot at DAMOP is quantum computing and quantum information. There are numerous schemes for using atomic or molecular systems to make a quantum computer, and the most highly developed quantum computing experiments in the world are the ion trap systems pioneered by Dave Wineland and his group at NIST. Again, this involves exploring fundamental questions of quantum mechanics and information, and even computer science, in an AMO context.

This happens again and again– there are fascinating atomic-based measurements of parity non-conservation and the like that use the power and precision of laser spectroscopy to address nuclear physics. There are the various EDM measurements, which actually get at some particle physics issues. There are the fine-structure constant measurements I talked about recently, that tie in to cosmology. And so on.

It’s striking that so much of the most interesting work in AMO physics these days is really based on using our detailed understanding of atoms, photons, and their interactions as a tool to explore problems from other areas of physics. There aren’t huge open questions dealing with the structure of atoms and simple molecules that need answering– or, at least, I couldn’t think of any this morning when I sat down to write this.

It’s kind of a weird situation, really, and makes it a little hard to really do the sort of blog series that Doug is proposing for condensed matter/ nanoscale physics.

On the other hand, a weekly on-line journal club (which is really what’s being proposed) might help me stay more plugged in to the hot topics in the field, so it’s tempting. I don’t know if there are enough AMO physicist readers to sustain it, though, and as Doug notes, it would only really work well if there were multiple contributors to the discussion.

Anyway, comments on the general idea, or suggestions of “hot topics” in AMO physics are welcome in the comments.