Ruminations on emergent phenomena in condensed phases of matter
Lecture on phase boundaries
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Here is tomorrow's lecture for PHYS2020: Thermodynamics and Condensed Matter Physics. I am finding it a challenge to come up with good questions for clickers. Any suggestions welcome.
if you use clickers the same way i do, then you want them to be 'supereasy' because they are done on the fly. so one i might ask is to show two free energies a la landau as a function of temperature, and pick out the one which has a first order transition, i.e. touches down with a finite order parameter.
another one is to show experimental data with a latent heat of some variety vs. one which is not 1st order.
maybe that helps. i didnt look through the slides before commenting in case you already did that.
I find clickers to be effectively used in two ways. Firstly is like greg said, it's a great wake-up thing, just to check to see if the students are paying attention at all, but the second method is the more important one in my opinion which involves getting the students to argue amongst themselves about why their answer is correct. For the trickier problems this produces critical thinking in the students as they're "forced" to reason through their answer and explain it to another person rather than going "well that's what I THINK the answer is..."
If you look on the arXiv and in Nature journals there is a continuing stream of people claiming to observe superconductivity in some new material. There is a long history of this and it is worth considering the wise observations of Robert Cava , back in 1997, contained in a tutorial lecture. It would have been useful indeed in the early days of the field [cuprate superconductors] to have set up a "commission" to set some minimum standard of data quality and reproducibility for reporting new superconductors. An almost countless number of "false alarms" have been reported in the past decade, some truly spectacular. Koichi Kitazawa from the University of Tokyo coined these reports "USOs", for Unidentified Superconducting Objects , in a clever cross-cultural double entendre likening them to UFOs (Unidentified Flying Objects, which certainly are their equivalent in many ways) and to "lies" in the Japanese translation of USO. These have caused g
Is it something to do with breakdown of the Born-Oppenheimer approximation? In molecular spectroscopy you occasionally hear this term thrown around. Google scholar yields more than 3000 hits. But I have found its precise meaning and the relevant physics hard to pin down. Quantum mechanics in chemistry by Schatz and Ratner is an excellent book , but the discussion on page 204 did not help me. "Herzberg-Teller" never appears in Atkins' Molecular quantum mechanics. So here is my limited understanding. Herzberg and Teller wanted to understand why one observed certain vibronic (combined electronic and vibrational) transitions that were not expected, particularly some that were expected to be forbidden on symmetry grounds. " Intensity borrowing " occurred. Herzberg and Teller pointed out that his could be understood if the dipole transition moment for the electronic transition depended on the nuclear co-ordinate associated with the vibration. In the Franck-Condo
I welcome discussion on this point. I don't think it is as sensitive or as important a topic as the author order on papers. With regard to paper authorship my general rule is that the person who does the bulk of the work, including actually writing the paper should be the first author. Doug Natelson has a good post on co-authorship , that I largely agree with. My only difference is that I am not really convinced that good practice prevails in the majority of circumstances. I fear there are increasing numbers of co-authors, particularly senior ones, with marginal contributions. But, what about conference talks and posters? Many of these are based on work that is already or about to be published. Should the author order be identical as the associated papers? I am not sure it should necessarily be. My tentative view is that the person who writes and submits the abstract and actually prepares and presents the post/talk should be the first author. Perhaps they should also highlig
if you use clickers the same way i do, then you want them to be 'supereasy' because they are done on the fly. so one i might ask is to show two free energies a la landau as a function of temperature, and pick out the one which has a first order transition, i.e. touches down with a finite order parameter.
ReplyDeleteanother one is to show experimental data with a latent heat of some variety vs. one which is not 1st order.
maybe that helps. i didnt look through the slides before commenting in case you already did that.
I find clickers to be effectively used in two ways. Firstly is like greg said, it's a great wake-up thing, just to check to see if the students are paying attention at all, but the second method is the more important one in my opinion which involves getting the students to argue amongst themselves about why their answer is correct. For the trickier problems this produces critical thinking in the students as they're "forced" to reason through their answer and explain it to another person rather than going "well that's what I THINK the answer is..."
ReplyDeleteThanks for the helpful suggestions.
ReplyDelete