Wednesday, November 02, 2011

Tunneling Experiment Proposed To Distinguish Superconducting Pairing Origin

It certainly was a nice coincidence that I mentioned about the paper on tunneling spectroscopy on superconductors earlier. It turns out that a new paper proposes an experiment using Josephson tunneling junction to distinguish between the pairing model proposed by 5 different theories.

Now, She et al. lay out in parallel the theoretical expectations for the pair susceptibility of 5 different theories of superconductivity in quantum critical metals. These scenarios include the orthodox BCS theory with a simple Einstein-oscillator pairing function, BCS with a Hertz-Millis-type criticality of the bosonic spectrum, BCS with a simple pairing function and quantum critical electrons, and two limits of the recently developed holographic superconductivity that borrow mathematical concepts from string theory [anti–de Sitter/conformal field theory (AdS/CFT) correspondence] in order to handle scaling near a quantum critical point.
It will be interesting to see which group gets to do this test first, and whether the results can actually distinguish one versus the others. Still, this is a prime example of the tunneling phenomenon being used to study other things.


1 comment:

Logan Wright said...

As a relative noob to quantum mechanics, or physics for that matter (I'll be finishing my undergraduate degree in May), I totally agree about the widespread usefulness of tunelling. I remember bow it was introduced as something of a "weird consequence" of the quantum theory in my first course. Since then the number of times it has come up in course material, new papers and presentations has relegated it to a decidedly less "weird" place in my perception of the world. It may help that I never had much time to develop an "electron is a ball of mass and charge" picture.

At any rate, this is great for those of us who aren't engaged in a sleepless race to publish the experiment.