To Unify Or To Mix?

A story about the power of words and of groupthink in fundamental physics.

While I was writing my free physics book, almost 30 years ago, I wrote an email to Sheldon Glashow. I asked him whether it is more correct to say that his famous work showed how the electromagnetic and the weak interaction unify or rather how the two interactions mix.

He confirmed that mixing is the better wording. Glashow is both a kind and great man. I also asked Weinberg, but he did not answer. Salam had already passed away.

Nevertheless, almost universally, “unification” is used instead of “mixing”. Even the Nobel committee used the term. However, this wording had a unexpected negative consequence, because the term “unification” is misleading. The term “unification” lead a generation of researchers (or even two) to try to unify interactions and to search for grand unified theories with various unified gauge groups. They had no success. A single misleading term sent thousands of researchers in the wrong direction.

Fifty years of experiments show that “gauge unification” or“unification of the interactions” do not occur in nature. Enormous effort went into these experiments. Nature disagrees even though most researchers agreed.

Had everybody — starting with the Nobel committee — consistently used the correct term “mixing” instead of the incorrect term “unification”, nobody would have wasted their time with the search for larger gauge groups that fail to describe nature. All experiments have always shown, since the very beginning, that there is no “gauge mixing” and no “grand mixing theory”.

The term “grand mixing theory” does not have the same charm as “grand unified theory”, does it? But in this case, they mean exactly the same.

This story shows the power of language to channel thoughts, dreams and projects. What do we learn from this? Two things.

First of all, the story implies that in large projects, even among the smartest people on Earth, there is groupthink. This is nothing new. In this case, groupthink delayed progress. And progress was delyed by many years! In fact, groupthink is a frquent problem in fundamental physics research. I already wrote about the mistaken claim that neutrino masses show that there is physics beyond the standard model. Then there is the supersymmetry groupthink. There is the additional dimensions groupthink. There is the groupthink that galaxy rotation curves disagree with the standard model. There are many additional examples.

All these cases of groupthink, taken together, have delayed progress so effectively that 50 years and hundred thousands of research publications have not yielded any progress in the foundations of physics. A huge effort by the smartest and brightest people on Earth led to no result.

Groupthink exists in every organisation and in every community. Groupthink reduces people to the level of artificial intelligence. Groupthink blocks progress. Groupthink blocks innovation.

Second, and here I think about the younger people: always question everything your teachers and everybody else tells you. Question every word and every argument. Check every argument in detail. Make up your own mind. As always in life, follow the maxim: sapere aude!