Condensed concepts

There are several independent lines of argument that are used to support the idea of a multiverse: the many-worlds interpretation of quantum mechanics, the ``landscape problem'' in string theory, and the fine-tuning of fundamental physical constants . Previously, I wrote about four distinct responses to the fine-tuning of the cosmological constant. I was recently trying to explain the above to a group of non-physicists. One of them [Joanna] had the following objection that I had not heard before. Schrodinger's cat can only exist in one universe within the multiverse. The multiverse involves zillions of universes. However, because of fine-tuning carbon-based life is so improbable that it can only exist in one (or maybe a handful?) of the universes, within the multiverse. Thus, when one observes whether the cat is dead or alive, and the universe ``branches" into two distinct universes, one with a dead cat and the other with a living cat, there is a problem. It is possi

It is that time of year again. I have not made predictions for a few years. For physics this year I predict Experiments for testing Bell inequalities and elucidating the role of entanglement in quantum physics Alan Aspect, John Clauser, and Anton Zeilinger They received the Wolf Prize in 2010, a common precursor to the Nobel. My personal preference for the next Nobel for CMP would be centred around Kondo physics, since that is such a paradigm for many-body physics, maybe even comparable to BCS. Kondo effect and heavy fermions Jun Kondo , Frank Steglich , David Goldhaber-Gordon Arguably the latter two might be replaced with others who worked on heavy fermions and/or Kondo in quantum dots. Steglich discovered heavy fermion superconductivity. Goldhaber-Gordon realised tuneable Kondo and Anderson models in quantum dots (single-electron transistors). Unlike many, I still remain to be convinced that topological insulators is worthy of a Nobel. For chemistry, my knowledge is

I previously discussed how one of the simplest model effective Hamiltonians that can describe many physical properties of spin-crossover compounds is an Ising model in an external "field". The s_i=+/-1 is a pseudo-spin denoting the low-spin (LS) and high-spin (HS) states of a transition metal molecular complex at site i. The ``external field" is one half of the Gibbs free energy difference between the LS and HS states. The physical origin of the J interaction is ``believed to be'' elastic, not magnetic interactions. A short and helpful review of the literature is by Pavlik and Boca. Important questions are: 1. What is a realistic model that can explain how J arises due to elastic interactions? 2. How does one calculate J from quantum chemistry calculations? 3. How does one estimate J for a specific material from experimental data? 4. What are typical values of J? I will focus on the last two questions. One can do a mean-field treatment of the Ising m

As years go by the PhD thesis in science and engineering is less and less of a ``thesis'' and more just a box to tick. There was a time when the thesis was largely the work of the student and tackled one serious problem. Decades ago at the University of Chicago, students were meant to write a single author paper that was based on their thesis. At some universities, including my own, students can now staple several papers together, write an introductory chapter, and submit that as a thesis. One obvious problem with that system is the question of how large was the contribution of the student multi-author papers, both in terms of the writing and doing the experiments or calculations. Previously I have argued that A PhD is more than a thesis , a PhD should involve scholarship , and a thesis should suggest future directions and be self-critical.  In some sense these posts were negative, focusing on what may be missing. Here I just want to highlight several positive things I recen