Turning away from particle accelerators

Physicists are always looking for new discoveries. They formulate models that can be used to explain as many observable phenomena as possible. With the help of experiments, carefully formulated questions to nature, as it were, it is then checked whether the assumptions and forecasts were correct or whether they need to be readjusted.

One of the best-known examples of a theoretical prediction is that of the British physicist Peter Higgs. In 1964 he had predicted the existence of a particle that is of particular importance for the theoretical structure. When the discovery of the Higgs particle, which had been sought after for decades, was finally announced in 2012, it was the culmination of the so-called standard model of physics - a comprehensive theory that can describe all known elementary particles and the four fundamental forces of nature.

In recent years, physicists have been talking more and more often about the "search for new physics" and do not mean the scientific progress that is always taking place anyway and on many fronts of knowledge. They mean a physics that can explain those things that the Standard Model has so far failed to explain. It's still a long way from the "theory of everything" that actually explains everything.

For one thing, it has still not been possible to integrate the gravitational force into the Standard Model. Also for the mysterious dark matter, for the existence of which there is solid indirect evidence in the universe, but no scientific explanation yet. The nature of dark matter, of which there is five times more than known "ordinary" matter, is still unclear. With "new physics" the scientists mean that one finally gets answers to these open questions, which are of course fundamental.

So far, the prevailing narrative has been that the decisive gain in knowledge can be expected with the help of ever larger particle accelerators and experiments at ever higher energies. After all, the important Higgs particle was discovered with the world's largest accelerator, the LHC, at the Cern research center in Geneva.

Recently, new sounds can be heard in the search for new physics. Perhaps the big open questions of physics can be answered in small research laboratories without huge, underground accelerator facilities? "The latest quantum technology enables laboratory experiments with unprecedented precision on the trail of new physics," says Joachim Ullrich, President of the German Physical Society. In fact, in recent years there have been extraordinary advances in the controlled handling of quantum particles - both light and matter quanta.

The researchers now hope to be able to use high-precision atomic clocks to detect dark matter passing by Earth in space. They expect that the gravitational pull of dark matter will minimally affect atomic clocks. New physics can also betray itself through changing natural constants or the violation of fundamental symmetries of space and time.

The atomic clocks available are so precise that if they had been started during the Big Bang 13.8 billion years ago, they would now be off by a maximum of one second. This unimaginably high level of accuracy enables experiments at low energies in small laboratories, where "new physics" effects may be observed.

This has not yet been achieved, but the scientists assume that the relevant technologies will become even more precise and powerful in the near future. They will be used to ask “critical” questions about the Standard Model and also about the theory of relativity.

It would be desirable for researchers to actually be able to gain new, fundamental insights with these comparatively inexpensive experiments. Because in view of the tense global economic situation due to various crises, it is currently quite questionable whether an even larger particle accelerator than the LHC can be financed at all.

"Aha! Ten minutes of everyday knowledge" is WELT's knowledge podcast. Every Tuesday and Thursday we answer everyday questions from the field of science. Subscribe to the podcast on Spotify, Apple Podcasts, Deezer, Amazon Music, among others, or directly via RSS feed.