204. Twitter updates for 2009-01-25

Evolutionary model for species body mass diversification: http://link.aps.org/doi/10.110…..102.038103 #evolution #prl # How precisely total cross-section will be measured at LHC? http://link.aps.org/doi/10.110…..102.032003 #LHC #PRL # @itscomplicated Sorry, that’s always the case with “Nature”. But the chance is that if you seat in the University, you can get it for free. in reply to itscomplicated # @beerzealot [...]

203. Quantum Hall effect. One open question

I cannot finish discussing quantum Hall effect without explaining why, after all those years of study, Laughlin wavefunction and composite fermions, it still remains interesting for a condensed matter theorist. The reason is existence of the state with is a fully spin polarized FQHE state described by so called Moore-Read wavefunction. Some people also think [...]

202. Twitter updates for 2009-01-24

Dissipative structures in supersonic turbulence http://link.aps.org/doi/10.110…..102.034501 #turbulence #hydrodynamics # Delusional brain: http://tinyurl.com/8ylkx6 # Good Saturday morning # Steven Chu addresses the National Labs: http://snipr.com/al5vf #chu #doe # Robots moving through the bloodstream in human body: http://is.gd/gWg9 #transhumanism #nanotechnology # Lubos Motl on EPR: http://snipr.com/al5yl #quantum #epr # Terence Tao on exactly solvable nonlinear wave equation [...]

201. Breaking Symmetry

Our universe has things in it because Chance quantum fluctuations enable. Nothing is what violates Nature’s laws – Something is apparently more stable. Super-symmetry was asking for it. It was just too perfect to be withstood, And once it took the predictable hit It lit up the entire neighbourhood, And in that Big Bang, the [...]

200. That’s right – two hundred

And THIS… IS… (let me say that again) a post number 200! I cannot believe my own eyes – it seems that I celebrated the post number 100 just a couple of months ago! As you can see, NEQNET grows relatively slowly but it grows. What has changed the last month? Many things. First of [...]

199. Twitter updates for 2009-01-23

Satellite shows enormous crowds at the Obama’s inauguration : http://short.to/mmp # College presidents say it’s time to lower the drinking age http://is.gd/gCbN # That’s fine, buddy. It is also good to offer a free drink for students who attend lectures # “Nature” says it’s better to go to Titan rather than to Europa http://short.to/mmq # [...]

198. Fractional quantum Hall effect – a few words about theory

Finally, after going through the integer quantum Hall effect, we are a kind of ready to discuss one of the biggest puzzles in condensed matter theory: the fractional quantum Hall effect. As you remember, it is also characterized by the quantization of the the Hall resistivity , (1) but the number in this formula acquires [...]

197. Twitter updates for 2009-01-22

Every day’s physics – what is stress tensor? http://twurl.nl/bzkd6e # Jacques Distler on topological quantum field theory: http://jijr.com/ige # This is an outline of long Lurie’s paper – very technical! # Klebanov and Maldacena on hyperbolic cows: http://is.gd/gGTU # This was Lubos Motl’s post about Klebanov and Maldacena’s paper in Physics Today: http://twurl.nl/i6xga2 # Jester [...]

196. Video of the day: How big is the Universe?

195. Integer quantum Hall effect – plateaus in Hall resistivity

This post is my attempt to give an answer to tg’s question: Ok, we a kind of proved that the Hall resistivity is quantized in the integer quantum Hall effect, but how to explain plateaus in the Hall resistivity and deep minima in diagonal resistivity as shown on the Fig. We have to introduce quite [...]