Thursday, October 23, 2014

Ask me something.

I haven't done this in a while.  Are there any particular subjects that you would like me to address, or concepts to explain?  It's a busy semester, but I can try....

Thursday, October 16, 2014

Some interesting links: Books and news

Here are some things that I wanted to share with my readership:
  • My friend Arjendu Pattanayak (founder of a very good blog) pointed out to me this book by Kittel.  It's really nice - it is very concise and tightly written without being incomplete, and it's cheap.
  • On a lighter note, Science...For Her! is a book by a friend of a friend.  The introductory video is here.  Attention Physics Today:  I volunteer to review this book when it comes out.  Seriously, I'd be happy to do it, and I think it would be great for some amount of wry humor to make its way into the pages of PT.  
  • Similarly, Randall Munroe's book What If? is magnificent.   Attention Physics Today:  I volunteer to review this one, also.  If you don't review this book, you are entirely humorless.
  • The MIT Technology Review has a fun article in it about topological quantum computing with non-Abelian anyons.  The reason it's fun is that it talks about the people involved (including my postdoctoral mentor) and manages to avoid becoming overly technical. 
  • A few people have pointed out to me that Lockheed Martin has made a rather strong press statement regarding a fusion reactor scheme being developed by Skunk Works (the folks who brought us the SR-71 and the F-117, among other things).   This is potentially interesting, but it's really hard to tell whether this is all vaporware so far.  It looks like a magnetic mirror configuration, something that has been explored extensively over the last few decades, and they don't provide enough technical discussion to figure out what they're doing that's different.  Still, there seem to be many takers trying alternatives to tokomaks (Washington, and what Nature termed "fusion upstarts"), and it's surely worth a shot.  
  • I listened in on a conference call today from Benefunder.  These people are trying to come up with an alternative philanthropic approach to research funding that isn't crowdsourcing.  Any commenters already sign up with them?

Tuesday, October 14, 2014

Quantitatively, how amazing are modern electronics technologies and materials?

I've talked before about how condensed matter/materials physics/engineering is so ubiquitous that it somehow fades into the background, and people don't appreciate how truly wondrous it is.  I thought I'd compile a few stats to try and drive this home.
  • A typical car contains something like 30,000 discrete parts, if you count down to the smallest individual screw.  By comparison, a typical microprocessor has around (to make the numbers work out conveniently) 3 billion transistors.  That's a factor of a million more constituents.  Bear in mind that essentially all of those transistors work, without fail, for a decade or more.  (When was the last time you actually had a processor failure, rather than a power supply or hard drive issue?).   Imagine taking a million cars, and claiming that they will all run, flawlessly, with no broken parts, for a decade.  
  • Parallel manufacturing is a wonderful thing.  If you built the 3 billion transistors serially at a rate of one per second, it would take around 95 years to put together a processor.  
  • There is a famous study that proved that Kansas is actually flatter than a pancake.  Perfect flatness would correspond with their flatness metric equalling 1, and they found that Kansas has a flatness of 0.9997.  By that measure, a 300 mm silicon wafer used to fabricate chips would have a flatness on the order of 1 - (30 nm/300mm) = 1 - 10-7.  If your dining room table was that flat, the typical height of a surface defect would be well under the wavelength of visible light.  If Kansas was that flat, the tallest feature in the state would be a few cm high.
  • The worst silicon purity acceptable for Si electronics processing is around 0.1 parts per billion.  That means that a single impurity atom in such silicon is more rare than, well, you as a member of the population of the earth.  
  • We have the ability to position particular devices with (roughly) few nm precision and accuracy on a processor of cm scale.  That's equivalent to being able to place an item on your desk in a particular place to within about 1/50th the diameter of a human hair.
If none of this impresses you, you're pretty jaded.

Thursday, October 09, 2014

Chapman Lecture - Paul McEuen

We were very fortunate last week to host Paul McEuen for our Chapman Lecture series (previous speakers here).  NAS member, successful novelist, director of LASSP at Cornell - typical underachiever.  The talk was tremendous fun, a look at several cool experiments going on in his lab examining the mechanical properties of graphene (which acts surprisingly like paper, and taught me about the Foppl/von Karman number, \(YL^2/\kappa\), where \(Y\) is the Young's modulus, \(L\) is a relevant length scale, and \(\kappa\) is the bending stiffness) and nanotubes.  The best part of the talk (apart from the rendition of the Cornell alma mater as played by electrically plucked carbon nanotubes) was the palpable sense of joy that he conveyed to the students in the audience.  He clearly really enjoys the playing-with-toys aspect of research!

Sunday, October 05, 2014

Annual Nobel speculation

It's that time of year again - go ahead and speculate away in the comments about possible Nobel laureates in physics or chemistry.  Natural suggestions in physics include Aharonov and Berry for geometric phases, Vera Rubin for dark matter/galaxy rotation curves, Charlie Kane and Shoucheng Zhang (and possibly Molenkamp) for topological insulators, Pendry, Smith, and Yablonovitch and John (oh dear that's four) for metamaterials and/or photonic bandgaps.

Update:  check out Slate's article on deserving women candidates.  Dresselhaus would be a good choice.  (I'm not as big a fan of, e,g., Lisa Randall, who is extremely smart but is in the space of high energy theorists who have not yet had predictions of exotic physics actually verified by experiment.)

Thursday, October 02, 2014

AAAS, Science magazine, and figure permissions

Hello readers - As I'd mentioned previously, I've written a nano textbook that's going to come out next year.  I'd like to ask my readership, on the off-chance that someone has a suggested contact:  Please email me if you can suggest a good contact at AAAS/Science, with whom I could have a discussion regarding figure permission fees.  (I'd like to try talking to someone first before turning this into a major blogging topic.)  Thanks.
Update:  I've made contact with an actual person.  We will see what happens....

Monday, September 29, 2014

Penny-wise, pound-foolish: Krulwich blog

I just read that NPR is getting rid of Robert Krulwich's excellent science blog, allegedly as part of cost-cutting.  Cost-cutting?  Really?  Does anyone actually think that it costs a huge sum of money to run that blog?  Surely the most expensive part of the blog is Robert Krulwich's time, which he seems more than willing to give.  Seriously, we should find out what the costs are, and have a kick-starter project to finance it.  Come on, NPR.