Science journalism - dark times

At this point it's old hat to decry the problems facing traditional news media.  Still, it is abundantly clear in our late stage capitalist society that there has been a collective business decision over the last 20+ years that, like local newspapers and television news, real science journalism is not a money maker.   Just a few examples:  Seventeen years ago, CNN cut its entire science, technology and environment reporting team.  In 2022, Popular Science ceased publication.  In 2023, National Geographic laid off their staff writers.  Last week, the Wall Street Journal laid off their science and health reporters.  

I have it on good authority that there is now only one science reporter left at the WSJ.  One, at a time when science and technology are more critically important to our rapidly changing society than ever, and there is enormous tumult in the US and elsewhere about how science is or is not supported and is or is not factoring into policy decisions.  All of this is happening at a time when public trust in science is falling.  (Check out this from Science Friday.)  

(updated for context) Leaving aside professional science outlets (the news sections of Science, Nature, and society publications like Physics Today, C&EN, Physics World, Chemistry World), there are some good publications out there, like Quanta and Nautilus (both founded by nonprofits). There are outstanding public writers of science, like Philip Ball, Helen Czerski, Katie Mack, Ethan Siegel, and many others (apologies for the incompleteness of this list).  There are some excellent freelance journalists.  The internet also means that there are many opportunities for great engagement.  For example, the videos from 3blue1brown are uniformly outstanding.  However, there are no filters, and the temptation to be click-baity or sensationalistic is problematic.  

I have no solutions to offer, except that I encourage you to support good science journalism and reporting when you see it.  It's important.

Interesting preprints: chirality-induced spin selectivity + quantum gravity

This continues to be a very busy time, but I wanted to point out two preprints that caught my eye this week.  Their subjects are completely disparate, but they stand out as essentially reviews written in a much more conversational tone than the usual literature.

The first is this preprint about chirality-induced spin selectivity, a subject that I've mentioned before on this blog.  There is now an extensive body of evidence (of varying quality) that there is a connection between structural chirality of molecules and their interactions with the spin angular momentum of electrons.  This includes monolayers of chiral molecules leading to net spin polarization of photoemitted electrons (here), a lot of electronic transport experiments involving chiral molecules and magnetic electrodes that seem to show spin-dependent transmission that is absent with achiral molecules, and even a chirality dependence of molecular adsorption kinetics on magnetic surfaces (here).  The preprint is a provocative discussion of the topic and possible mechanisms, and the importance of precision in the description of the various phenomena.

On a completely different topic, this preprint is a fun discussion about quantum gravity (!) and how condensed matter ideas of "the vacuum" can lead to insights about how quantum mechanics and gravity might need to play together.  One fun bit early on is a discussion of something I like to point out to my undergrad stat mech students:  A single hydrogen atom in a very very large box will apparently (if the usual stat mech formalism of partition functions is valid) be spontaneously ionized, even when the box and atom are at temperatures faaaaaar below the energy scale for ionization.  This is discussed nicely in this 1966 article in the Journal of Chemical Education.  Anyway, I thought this was an interesting discussion from three condensed matter theorists.

Postdoctoral opportunity in materials

The Rice Advanced Materials Research Institute is having its 2025-2026 competition for prestigious postdoctoral fellowships - see here:  https://rami.rice.edu/rami-postdoctoral-fellowship-program  .

If you are interested and meet the criteria, I'd be happy to talk.  I have some ideas that lean into the materials for electronics direction, and other possibilities are welcome.  

2025 Physics Nobel: Macroscopic quantum tunneling

As announced this morning, the 2025 Nobel Prize in Physics has been awarded to John Clarke, Michel Devoret, and John Martinis, for a series of ground-breaking experiments in the 1980s that demonstrated macroscopic quantum tunneling. 

For non-experts: "Tunneling" was originally coined to describe the physical motion of a quantum object, which can pass through a "classically forbidden" region.  I've written about this here, and here is an evocative picture. Suppose there is a particle with a certain amount of total energy in the left region.  Classically, the particle is trapped, because going too far to the left (gray region) or too far to the right (gray region) is forbidden:  Putting the particle inside the shaded regions is "classically forbidden" by conservation of energy.  The particle bounces back and forth in the left well.  If the particle is a quantum object, though, it is described by a wave function, and that wave function has some non-zero amplitude on the far side of barrier in the middle.  The particle can "tunnel" through the barrier, with a probability that decreases exponentially with the height of the barrier and its width.

Fig. 2 from here

Clarke, Devoret, and Martinis were working not with a single particle, but with electrons in a superconductor (many many electrons in a coherent quantum state).  The particular system they chose was a Josephson junction made from an oxide-coated Nb film contacted by a PbIn electrode with a dc current flowing through it.  Instead of an x coordinate of a particle, the relevant coordinate in this system is the phase difference \(\delta\) of the superconducting wave function across the junction.  There is an effective potential energy for this system called a "washboard" potential, \(U(\delta)\), as in this figure.  At the particular DC current, which tilts \(U(\delta)\), the system can transition from one state (\(\delta\) bopping around a constant value, no voltage across the junction) to a state where \(\delta\) is continuously ramping (corresponding to a nonzero voltage across the junction).  The system can get thermally kicked from the zero voltage state to the nonzero voltage state (thermal energy doinks it over the barrier), but the really interesting thing is that the system can quantum mechanically tunnel "through" the barrier as well.

This idea, that a macroscopic (in the sense of comprising many many electrons) system could tunnel out of a metastable state like this, had been investigated by Amir Caldeira and Tony Leggett in this important paper, where they worried about the role of dissipation in the environment.  People tried hard to demonstrate this, but issues with thermal radiation and other noise in the experiments were extremely challenging.  With great care in experimental setup, the three laureates put together a remarkable series of papers (here, here, here) that showed all the hallmarks, including resonantly enhancing tunneling with tuned microwaves (designed to kick the system between the levels shown in panel (d) of the figure above).  

This was an impressive demonstration of controllable, macroscopic quantum tunneling, and it also laid the foundation for the devices now used by the whole superconducting quantum computing community.  

ACS National Nanotechnology Day webinar, Thursday Oct 9

Time for a rare bit of explicit self-promotion on this blog.  This coming Thursday, October 9, as part of the American Chemical Society's activities for National Nanotechnology Day (Why October 9?  In US convention, Oct 9 = 10/9, and 10^-9 m = 1 nm.  Look, it wasn't my idea....), I'm speaking in a free webinar titled "Illuminating the Nano Frontier", with Prof. Dongling Ma of INRS in Quebec.  The event is 11am-12:30pm EDT, and there will also be a recording for people who are unable to watch it live.  Should be a fun event. 

Update:  Here is the link to the webinar recording.  It's free and open-access.