Wednesday, March 31, 2010
I learned so many things from him just by observing how he ran the weekly brown bag lunches with his graduate students and later mine--listening with great interest as they described their research progress. He asked insightful and penetrating questions, but not in a threatening manner, made suggestions, and frequently went to visit the labs late in the day to see what was going on. He also hosted many undergraduate research students. He was devoted to education and student training and would prepare as carefully for lectures to freshman chemistry classes as for presentations to prestigious assemblages of scientists.
Tuesday, March 30, 2010
Monday, March 29, 2010
Sunday, March 28, 2010
Friday, March 26, 2010
Thursday, March 25, 2010
Wednesday, March 24, 2010
Tuesday, March 23, 2010
"The preexisting magnetic singlet pairs of the insulating state become charged superconducting pairs when the insulator is doped sufficiently strongly."
- average scores on student evaluations of teaching
- impact factors of journals
- citation rates per paper
This site reports "large changes" in impact factors of Chemistry Journals from 2007 to 2008. It reports that of ChemPhysChem changed from 3.502 to 3.636.
Monday, March 22, 2010
Sunday, March 21, 2010
Friday, March 19, 2010
Wednesday, March 17, 2010
Tuesday, March 16, 2010
Monday, March 15, 2010
Sunday, March 14, 2010
the era of the great breakthrough is over..... I have found that when I suggest to senior physicists that the end of physics as we know it is in sight, they tell me, "That's just what everybody was saying in 1900". Now this may be a justification for optimism, but let's first ask whether the historical parallel is sound. I think in many ways it is.
....If you don't believe me, ask yourselves this question: Apart from the field of fundamental particles, what is the most recent discov- ery in physics that still remains in essence a mystery? I think I might remark that in low-temperature physics the disappearance of liquid helium, superconductivity, and magneto-resistance from the list of major unsolved problems has left this branch of research looking pretty sick from the point of view of any young innocent who thinks he's going to break new ground.
....but with the new IBM Laboratory, and all those other labs that we represent, plugging along assiduously doing research, ten years is going to see the end of our games as pure physicists,....
Note, that the same time Pippard was giving this talk his very own Ph.D student, Brian Josephson was making a discovery that led to elucidation of spontaneously broken symmetry, macroscopic quantum tunneling, .....
Saturday, March 13, 2010
Friday, March 12, 2010
Wednesday, March 10, 2010
Tuesday, March 9, 2010
In Mike Norman's nice review of the theory of superconductivity in the cuprates he states:
The RVB spin gap was probably the first prediction for the subsequently observed pseudogap phase. In RVB theory, the pseudogap phase corresponds to a spin singlet state (with its resulting spin gap) but no phase coherence in the charge degrees of freedom. One of the interesting ideas to emerge from this was an explanation for transport in this phase, which reveals a metallic behavior for in-plane conduction, but an insulating behavior for conduction between the planes. In the RVB picture, the metallic behavior is due to the fact that the holons can freely propagate. But to tunnel between the planes, the holons and spinons must recombine to form physical electrons, and this costs the spin gap energy, thus one obtains insulating like behavior for the c-axis conduction (Lee, Nagaosa, Wen, 2006). This “gap” has now been directly seen in c-axis infrared conductivity data (Homes et al., 1993).
However, it seems to me that there is now an alternative hypothesis to explain the c-axis infrared conductivity data, which does not require this exotic recombination of holons and spinons into an electron. This is provided by a paper by Michel Ferrero, Olivier Parcollet, Gabriel Kotliar, and Antoine Georges, discussed in this earlier post. The difference between in plane and interplane transport arises simply from the wavevector dependence of the interplane hopping matrix element. But, the observed gap is still due to the pseudogap.
Monday, March 8, 2010
Saturday, March 6, 2010
Even if quantum computing remains a dream, the physics of quantum information processing at the level of a few qubits is fascinating. Experiments on entangled particles with ions in a trap or atoms in a cavity will help us understand the fundamental aspects of quantum measurement theory, and they may lead to major improvements in the precision spectroscopy of simple quantum systems..... Testing quantum decoherence in conceptually simple experiments is also an important and challenging task. Rather than teaching us how to build a large quantum computer, such experiments are more likely to teach us about the processes that would ultimately make the undertaking fail. It is important to advertise this fascinating subfield of quantum optics for what, it really promises, which is a deeper insight into the most counterintuitive theory yet discovered by physicists.
- the emphasis that computational chemistry should be motivated by and ultimately connect with experiment
- the figures are key