Friday, November 22, 2024

Brief items

 A few tidbits that I encountered recently:

  • The saga of Ranga Dias at Rochester draws to a close, as described by the Wall Street Journal.  It took quite some time for this to propagate through their system.  This is after multiple internal investigations that somehow were ineffective, an external investigation, and a lengthy path through university procedures (presumably because universities have to be careful not to shortcut any of their processes, or they open themselves up to lawsuits).
  • At around the same time, Mikhail Eremets passed away.  He was a pioneer in high pressure measurements of material properties and in superconductivity in hydrides.
  • Also coincident, this preprint appeared on the arXiv, a brief statement summarizing some of the evidence for relatively high temperature superconductivity in hydrides at high pressure.
  • Last week Carl Bender gave a very nice colloquium at Rice, where he spoke about a surprising result.  When we teach undergrad quantum mechanics, we tell students that the Hamiltonian (the expression with operators that gives the total energy of a quantum system) has to be Hermitian, because this guarantees that the energy eigenvalues have to be real numbers.  Generically, non-hermitian Hamiltonians would imply complex energies, which would imply non-conservation of total probability. That is one way of treating open quantum systems, when particles can come and go, but for closed quantum systems, we like real energies.  Anyway, it turns out that one can write an explicitly complex Hamiltonian that nonetheless has a completely real energy spectrum, and this has deep connections to PT symmetry conservation.  Here is a nice treatment of this.
  • Just tossing this out:  The entire annual budget for the state of Arkansas is $6.5B.  The annual budget for Stanford University is $9.5B.  
More soon.

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