Einstein on Faster-Than-Light (FTL) particles?

Robert Ehrlich, George Mason University

In one of his famous 1905 papers on relativity Einstein said that “Velocities greater than that of light have … no possibility of existence.” This statement was made after he noted that the energy needed to accelerate an electron to v = c would be infinite, so his proscription against v > c particles was specifically in reference to objects that start out with sub-light speeds. It is unclear what Einstein might have thought about v > c particles (tachyons) that had superluminal speeds from the very moment of their creation in subatomic particle collisions – an idea suggested by Bilaniuk, Deshpande, and Sudarshan in 1962. Such particles would obey the equations of special relativity and hence have an imaginary rest mass or a negative value of m². Of course all searches for these hypothetical particles have proven negative, and there have also been many false reports over the years – the latest being the famous OPERA experiment at CERN in 2011. The initial OPERA result was shown to be due to several errors, including a loose cable. These false reports over the years have probably made most physicists very skeptical of the whole idea of tachyons, although there continues to be a small group who believe that one or more of the neutrinos may indeed be tachyons, with a negative m² so close to zero, that it would have so far escaped detection. The author happens to be among this group, and he believes that there exists a number of experimental indications (though certainly no clear proof yet) that one neutrino is a tachyon – results he has published in a number of papers.

In an effort to overcome what he considers the “tardycentrism,” i.e., a misguided unwillingness to seriously consider the evidence for tachyonic neutrinos, the author has recently created a humorous video of a cartoon Einstein giving his views on the subject. Of course, it is not possible to know what Einstein, if he were alive today, might make of the possibility of tachyons existing. Nevertheless, given Einstein’s fondness for unconventional thinking and entertaining ideas out of the mainstream, it is quite possible he would share the views of Richard Feynman, who when asked by a graduate student several decades ago whether he thought tachyons really existed, replied “Of course.” The author’s 16 minute long video entitled “Einstein on Faster-than-Light Particles?” can be found on YouTube, and it should be understandable to viewers having only a very modest amount of basic physics.

For those readers interested in the mechanics of creating such videos, the following is worth noting. The author is relatively unskilled at computer animation, but once he created a detailed script, he was able to put the project out for bid, with the whole thing costing under $2300 – although some bids were for many times that figure. There were over 30 people bidding to do the voice over, and around 10 animation companies bidding to create the video itself – most outside the U.S.  He awarded the project to an India-based company (AFX Animation) with whom he has worked on a variety of media projects in the past, and was very pleased with the end result. Of course, following the 2011 “Phantom of the OPERA”, now may not be the greatest time to stimulate interest in the notion that neutrinos may indeed be tachyons, but perhaps the video might prove to be of interest to students who find very appealing the notion that there are still many undecided extremely fundamental questions in physics that do have empirical answers.

Disclaimer–The articles and opinion pieces found in this issue of the APS Forum on Education Newsletter are not peer refereed and represent solely the views of the authors and not necessarily the views of the APS.