All That Matters

A scanning tunnelling microscope image of a single-atom transistor during fabrication. The pink colours represent the areas where a single phosphorus atom (centre) as well as phosphorus source and drain contacts will be placed. The gate contacts that control the transistor action from the side are not visible here. Credit: Martin Fuechsle

When Gordon Moore made his observation in 1965 that the number of transistors integrated on a single silicon chip is doubling roughly every two years, the only logical end point for such a trend would be a transistor made from a single atom. This point has now been reached. Writing in Nature Nanotechnology, Michelle Simmons from the University of New South Wales in Sydney and colleagues report a single-atom transistor, the world’s smallest, on a silicon chip. The transistor is based on current flowing through a single atom of phosphorus embedded in a silicon wafer. […]

The young Max Planck, when completing his high school degree, asked a professor of physics at the University of Munich, Philipp von Jolly, whether he should study physics. He got the famous answer that this wouldn’t make much sense, because physics is an almost fully mature science with not much to discover. (If you happen to speak German, it is worth reading the original text, reprinted in this biography of Max Planck.)

Of course, luckily Planck ignored this advice and went on to make some of the most profound discoveries in modern physics. And well, if you think we are in a similarly dull situation in physics at present, the past few weeks would have certainly disproved this, because a couple of intriguing, unpublished (in the academic sense) research findings have appeared widely in the news: neutrinos that continue to appear to be faster than the speed of light, a completely new view on wavefunctions in quantum mechanics, and it seems also that there isn’t much hiding space left for the Higgs boson, if it exists.

Arthur Eddington's 1919 photograph of the sun during a total eclipse. The position of the stars appearing behind the sun verified Einstein's theory of relativity. Photo via Wikimedia.

Those discoveries all come with the promise of significant changes to our understanding of physics, and we’ve seen some exposure in the news (and the occasional hype, too). This is perhaps not surprising. The neutrino experiment questions the theory of relativity. The absence of the Higgs boson on the other hand would open the question again about the different masses of particles. And the new view of wavefunctions seems to add further to the arguments whether the wavefunctions in quantum mechanics are purely an expression of probability to find an object in a certain physical state, or are a representation of actual reality. The paper now rules out the possibility that wavefunctions are probabilistic states, but still having an underlying reality. Instead, there are two interpretations left. One can either fall back to the argument that there is no underlying reality in quantum mechanics and wavefunctions simply are nothing but probabilistic. Or, the second option is that wavefunctions are an expression of actual reality, abandoning the probabilistic interpretation. Not surprisingly, for this reason the paper got lots of headlines. Most people my colleagues at Nature spoke to were quite enthusiastic, whereas Scott Aaronson didn’t seem to see that much of a surprise. Matt Leifer has an informative, quite detailed description of the paper on his blog. […]

You may imagine vacuum as complete emptiness, as the very definition of nothing. But that’s not the case at all. Vacuum is humming with activity, as has now been demonstrated impressively in a study by researchers from Chalmers University of Technology in Göteborg, Sweden, RIKEN in Japan, the University of Michigan in the US and other institutions. They have created light basically out of nothing but the electromagnetic fields existing even in total vacuum.

Where does this contradiction come from that vacuum isn’t really ever empty? One of physics fundamental laws of physics, Heisenberg’s principle, states that even in vacuum virtual particles can exist. These are particles that appear only for such brief moments of time that they’re not noticeable to an observer. Indeed, vacuum is buzzing with all sorts of virtual particles and fields. One of Stephen Hawking’s most well-known predictions is that black holes emit light, which is an effect that relies on virtual particles. […]