Condensed concepts

Sometimes I never get around to writing or finishing planned blog posts. Last month something changed, but nothing changed for me. None of this is covid-related. Three years ago I negotiated with my university a "transition to retirement" contract. These seem to be designed by the accountants to incentivize "highly paid old farts" to retire (regardless of whether they have anything to contribute) and make the university "financially sustainable". I got to go half-time for three years with no teaching and administrative responsibilities.  (BTW. I actually love teaching. I just don't enjoy it or see the point when it becomes bureaucratic and/or students are disengaged.) Pretty strong incentive! I did this for a multitude of reasons: mental health, other opportunities and priorities, an unwillingness to take on administrative roles that seem to be mostly implementing dubious management decisions, and general concerns about where Australian universities ar

A range of isotope substitution experiments have been performed on spin-crossover materials.  Just like for other systems such as superconductors their interpretation is subtle. The first studies are reviewed in Section 2.3.5 of   this review article. Isotopic exchange was investigated for a tris(picolylamine)iron(II) system which exhibits a two-step spin transition. Results are shown in the figure below. Significant changes in the spin-state transition curve were observed only when the isotopic substitution (H/D and 14N/15N) was made for atoms directly involved in the hydrogen-bonding network that connects the spin-crossover molecules. For example, with C2H5OD/ND2 the crossover temperature was shifted to higher temperatures by about 15 K and the middle step was no longer present.  I would not have expected such a large effect given the chemical complexity of these systems and that the H atoms are not immediately bonded to the iron atoms which undergo the spin-state transition. I now

 Isotopic substitution has provided significant insights into molecular and solid-state physics. This involves the substitution of particular atoms in a compound by the same chemical element with a different nuclear mass (i.e. a nuclear isotope). An example is hydrogen/deuterium substitution which has shown the significant role that quantum nuclear motion can play in hydrogen bonding , particularly in strong hydrogen bonds. Of particular relevance to the discussion below is that isotopic substitution does not only change vibrational frequencies but can also change bond lengths.   A key piece of evidence on the road to the BCS theory of superconductivity in 1957 was the observation of an isotope effect. In 1950 a shift in the transition temperature of mercury was observed, suggesting that superconductivity resulted from electron-phonon interactions, as argued by Frohlich that same year. In particular, the magnitude of the shift was consistent with theoretical work by Herbert Frohlich .

How would you define condensed matter physics? In 250 words how might you motivate someone to want to know more. For Condensed Matter Physics: A Very Short Introduction,   I need to write a brief blurb (about 250 words) that will be used for marketing. Here is my first attempt. What do you think? There are many more states of matter than just solid, liquid, and gas. Examples include liquid crystal, magnet, glass, and superconductor. New states are continually being discovered leading to a stream of Nobel Prizes. Some states, such as superfluid and superconductor, exhibit the weirdness normally associated with the quantum physics of single atoms, such as Schrodinger's cat. Condensed matter physics seeks to understand how states of matter and their distinct physical properties emerge from the atoms that a material is composed of. Materials and states studied by condensed matter physicists are central to modern technology. Examples include superconductors in hospital MRI machines, mag

 My wife and I watched the movie, Radioactive , based on the life of Marie Sklodowska Curie.  She was an amazing scientist who showed incredible perseverance, particularly in the face of discrimination by the scientific establishment in France at the beginning of the twentieth century, and attacks in the media because of her gender, nationality, and personal life.   The movie is good entertainment and creative, maybe a bit too creative at times. But they be a matter of personal taste. There were many things that I learnt, some substantial and others just interesting trivia, particularly after reading more on Wikipedia. Here are a few. Curie did not only discover radioactivity, the elements radium and polonium (named after her native Poland), but also was the founder of nuclear medicine.  One can easily forget that more than a century ago, chemistry labs were very basic and that producing pure samples was a tedious process. For example, a tonne of pitchblende (uranium oxide ore) h

 Most Ph.D. students and postdocs will end up employed outside academia and doing work that is not related to their current research. For this reason alone it is important to learn a broad range of skills beyond what is needed to publish that paper in a luxury journal that their supervisor craves.  Furthermore, for faculty to survive, let alone flourish, in today's university (corporate) environment soft skills are very important. David Sholl (a frequent commenter on this blog) has just published a relevant book. Here is the publisher blurb. Long-term success in scientific research requires skills that go well beyond technical prowess. Success and Creativity in Scientific Research: Amaze Your Friends and Surprise Yourself i s based on a popular series of lectures the author has given to PhD students, postdoctoral researchers, and faculty at the Georgia Institute of Technology. Both entertaining and thought-provoking, this essential work supports advanced students and early career

Being in a management position is neither a necessary nor a sufficient condition for academic leadership. Senior managers at Australian universities sometimes wax lyrical about how they are in leadership. When it comes to promotion decisions, they also judge junior academics on whether they show "leadership".  This seems to be equated with the size of one's research group and the number of one's citations. The rise of this fixation on "leadership" in universities was highlighted by a commenter on a recent post. This misunderstanding is another example of how university management does not actually consider what their own academics in the university may actually know. Leadership is a well-researched topic. If managers talked to faculty in business and history, they might be told something along the following lines.                                                             The cartoon is from here. Real leadership is characterised by influence. It leads to

 In Condensed Matter Physics: A Very Short Introduction I would like to include an Appendix with  a list of all the Nobel Prizes related to condensed matter physics. My list includes 31 in Physics and 6 in Chemistry. I acknowledge that a few in my list are debatable. Some of the Chemistry prizes were to people who trained in condensed matter physics but eventually worked in chemistry departments. A few of the physics prizes are closer to electronic engineering than condensed matter. On the one hand, Nambu was not a condensed matter physicist, but he took Anderson's ideas about broken symmetry in superconductivity and applied them to particle physics. I want to include the list because I find it pretty amazing and it illustrates just how CMP consistently seems to turn up surprising new discoveries. Many of these prizes are mentioned in the text of the VSI. In writing the book, and particularly the chapter on topological quantum matter , I found that nobelprize.org is very helpfu