- 2d metal-insulator transition - What is the mechanism for the apparent metal-insulator transition in 2d electron and hole systems at low densities? Is it profound or not?
- High-Tc - what is the mechanism of high temperature superconductivity? What is the ultimate limit of Tc? What is the "bad metal", and what is the pseudogap, really? How important are stripes and checkerboards? Is the phrase "doped Mott insulator" really a generic description of these systems?
- Quantum criticality and heavy fermions - Do we really understand these systems? What are the excitations in the "local moment" phase? What is the connection to high-Tc, if any?
- Manganites - What sets the length scale for inhomogeneities in these materials?
- Quantum coherence and mesoscopics - Do we really have a complete understanding of mesoscopic physics and decoherence at this point? What about in correlated materials?
- Quantum Hall systems - Are there really non-Abelian states at certain filling factors? In bilayers, is there excitonic condensation?
- 1d systems - Is there conclusive evidence of spin-charge separation and Luttinger liquid behavior in semiconductor nanowires? Nanotubes?
- Mixed valence compounds - Is there or is there not charge ordering at low temperatures in Fe3O4, something that's been argued about for literally 60 years now?
- Two-channel Kondo physics - Is there firm evidence for the two-channel Kondo effect and non-Fermi liquid behavior in some physical system?
- Molecular electronics - Is there really improving agreement between experiment and theory? Can novel correlation physics be studied in molecular systems? Can molecules exhibit intrinsic (to the molecule) electronic functionality?
- Organic semiconductors - What is the ultimate limit of charge mobility in these materials? Are there novel electronic correlation effects to be seen? Can one see a metal-insulator transition in these systems?
- Nanomechanical systems - Can we demonstrate true "quantum mechanics", in the sense of a mechanical system that acts quantum mechanically?
- Micro/nano systems to address "fundamental physics" - Can we measure gravity on the 100 nm length scale? Are there experiments with Josephson junctions that can probe "dark energy"?
Wednesday, August 02, 2006
hot topics and controversies
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. Here are a few off the top of my head:
Posted by Douglas Natelson at 8:05 AM