Here are a couple of neat papers that I came across in the last week. (Planning to write something about multiferroics as well, once I have a bit of time.)
- The idea of directly extracting useful energy from the rotation of the earth sounds like something out of an H. G. Wells novel. At a rough estimate (and it's impressive to me that AI tools are now able to provide a convincing step-by-step calculation of this; I tried w/ gemini.google.com) the rotational kinetic energy of the earth is about 2.6×1029 J. The tricky bit is, how do you get at it? You might imagine constructing some kind of big space-based pick-up coil and getting some inductive voltage generation as the earth rotates its magnetic field past the coil. Intuitively, though, it seems like while sitting on the (rotating) earth, you should in some sense be comoving with respect to the local magnetic field, so it shouldn't be possible to do anything clever that way. It turns out, though, that Lorentz forces still apply when moving a wire through the axially symmetric parts of the earth's field. This has some conceptual contact with Faraday's dc electric generator. With the right choice of geometry and materials, it is possible to use such an approach to extract some (tiny at the moment) power. For the theory proposal, see here. For an experimental demonstration, using thermoelectric effects as a way to measure this (and confirm that the orientation of the cylindrical shell has the expected effect), see here. I need to read this more closely to decide if I really understand the nuances of how it works.
- On a completely different note, this paper came out on Friday. (Full disclosure: The PI is my former postdoc and the second author was one of my students.) It's an impressive technical achievement. We are used to the fact that usually macroscopic objects don't show signatures of quantum interference. Inelastic interactions of the object with its environment effectively suppress quantum interference effects on some time scale (and therefore some distance scale). Small molecules are expected to still show electronic quantum effects at room temperature, since they are tiny and their electronic levels are widely spaced, and here is a review of what this could do in electronic measurements. Quantum interference effects should also be possible in molecular vibrations at room temperature, and they could manifest themselves through the vibrational thermal conduction through single molecules, as considered theoretically here. This experimental paper does a bridge measurement to compare the thermal transport between a single-molecule-containing junction between a tip and a surface, and an empty (farther spaced) twin tip-surface geometry. They argue that they see differences between two kinds of molecules that originate from such quantum interference effects.