"Life is dewy, art is a thousand autumns." Whenever I read reports of experimental physicists seeking evidence for the wonderful conjectures of theoretical physicists (like me) without finding nothing, I can't help but think of hippocrates' aphorism. Like art, the road to science is incomparably long.
In those frustrating moments, I often use history to motivate myself: just as water boils before it boils, scientific research goes through a long gestation before it succeeds.
Einstein predicted gravitational waves (a direct result of general relativity) predicted in 1916 and were not first detected experimentally until 100 years later, in 2016. Subatomic particles such as the Higgs boson are luckier, with a "mere" 50-year interval between prediction and discovery. In the early 1960s, theoretical physicists proposed that if some kind of invisible particle fills the entire space and forms a homogeneous substance (Higgs field), we can describe known elementary particles more consistently and beautifully. But it wasn't until 2012 that scientists managed to smash the Higgs field and confirm the existence of the Higgs boson.
Another example is the cosmic microwave background radiation that brings us a wealth of information about the Big Bang. As early as 1948, scientists proposed a theory: the photons of the early universe cooled during the expansion of the universe, forming microwave radiation that filled the current space. Although the researchers detected microwave background radiation early on, they only saw a vast expanse with no characteristic structure. It wasn't until 1992 that scientists first observed the imprints left on the microwave background radiation at the beginning of the universe. Behind all these scientific explorations is the silent cultivation of countless experimental scientists for many years. We often receive so-called "progress reports" that say there is really no progress. When there is a perfect ending, it may be taken for granted in retrospect, but before that, it seemed so unlikely. Many people have lost hope in the process.
So what other "sleepers" in physics today are waiting to be awakened? I have the following speculations and expectations.
Proton decay counts as one. To understand why so many elementary particles exist, we hypothesize that there is such a physical process that can transform one elementary particle into another, specifically by turning the quarks that make up protons into lighter particles, thereby making protons unstable. Frustratingly, although researchers began experimenting in the 1970s to look for this phenomenon of proton decay, nothing has been found so far. However, some rather tantalizing theories suggest that the discovery of proton decay should not be far away, until more sensitive detectors are available.
Another sleeper that I've been thinking about is a particle called an axion. We need axles to explain a magical, god-given property of the fundamental laws of nature, namely, the reversibility of time. Of course, this is not the case in real life, and if you play a movie backwards, it will look completely wrong.
In 1977, Steven Weinberg and I independently based ourselves on the work of Helen Quinn and Roberto Peccei to propose the axle hypothesis. At that time I used the name of a detergent to call the shaft, because it can "wash" our perception of the reversibility of time. I was optimistic, thinking that the shaft would be discovered in a few months. It was the most exciting period of my career. Many experimental physicists around the world are scrambling to find axions. But, alas, they found nothing.
But a more general version of axion theory has gained widespread support, not least because it offers a beautiful solution to what cosmologists call "dark matter." Dark matter is a ghostly substance, and based on its gravitational pull, we can tell that it accounts for a large part of the total amount of matter in the universe. The axion has the right properties to act as this mysterious substance. So when a new generation of experimental physicists began to build the equipment needed to observe the particles, axion theory became exciting again.
The quest for answers to questions is so long that one can't help but feel jealous of the protagonist of Woody Allen's movie The Sleeper: a man who has been sleeping for years just opens his eyes and sees the future. However, a good suspense novel, if you directly turn to the ending, it is too boring. Long anticipation will make the final result more delicious.
Article excerpt from Global Science