YOU don’t generally think of electrons as nervous. Yet observe one closely enough and that is exactly how it might appear. As it zips through the vacuum, the lightest known fundamental particle displays a super-fast trembling motion whose name every Scrabble player in the world ought to have firmly in the front of their mind: Zitterbewegung.
“As it zips though the vacuum the electron exhibits a super-fast trembling motion”
The phenomenon was discovered in 1930 by Austrian physicist , one of the founding fathers of quantum theory, that fabulously successful description of the microscopic world of atoms and their constituents. At the time he was playing around with the ““, which British physicist had devised two years earlier to describe an electron travelling at close to the speed of light. The Dirac equation contained a bombshell: it predicted a whole new set of subatomic particles known as “antiparticles”, whose properties were opposite to those of the known particles. But this was not what caught Schrödinger’s attention.
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It seemed to him that if you delved deeply into the Dirac equation a further property emerged: as an electron flew through the vacuum, it would undergo a curious jittery motion, known as Zitterbewegung in German. Schrödinger’s calculations predicted that the electron would flit back and forth like a bee in a box, though the “box” in this case was a volume of space hundreds of thousands of times bigger than the size of the electron. Nobody has observed Zitterbewegung directly, mainly because it is mind-bogglingly fast: the electron flits back and forth something like a billion billion billion times every second.
In recent years there has been renewed interest in Zitterbewegung among researchers interested in , the restless seething of the vacuum that is a consequence of quantum theory. Zero-point energy manifests itself in the form of countless subatomic particles and their antiparticles, which pop fleetingly in and out of existence. Could Zitterbewegung be the result of the ceaseless buffeting that an electron receives from this roiling vacuum, rather than an intrinsic property of the electron itself?
The American physicist Hal Puthoff, director of the Institute for Advanced Studies in Austin, Texas, has gone one step further. In 1989, he that in the process of Zitterbewegung, the energy transferred to an electron by the buffeting of the vacuum is precisely represented by the equation E = mc2, where m is the mass of the electron. What this means is that an electron has no intrinsic mass, only an effective mass bestowed by the vacuum. Even die-hard proponents of this idea, however, accept that a lot more work is needed to firm it up.
