Exploring the mysterious substance “dark matter” of the universe on the table: Contents of the “ultra-compact” experiment out of common sense | WIRED.jp

Death and taxes are the only certain things in life, but a physicist might add a “fundamental physical constant.” Fundamental constants of physics are things that physicists have identified as constant throughout the universe, such as the speed of light or the mass of electrons.

But is this really immutable?

Therefore, the experiment of irradiating a small glass container containing iodine gas with a green laser was carried out by a research team of physicist Dionysius Antipas belonging to the Institute of Johannes Gutenberg University Mainz in Germany. By carefully observing the interaction of light and iodine, they looked to see if certain fundamental physical constants changed even slightly over time.

“We call it ‘constant’ in brackets,” says Antipas.

Simply put, the iodine molecule is two atoms connected by a spring. When you shine light of a particular frequency or color on it, the two atoms absorb the light and vibrate back and forth. By adjusting the color of the light, Antipas searched for the frequency at which this occurred.

This frequency is determined by several fundamental physical constants, including the nuclear mass of the iodine atom, the electron mass, and the strength of the interaction between the charge and the electromagnetic field, called the fine structure constant. By identifying the nature of the light absorbed by the molecule, we can determine whether the fundamental physical constants change.

In conclusion, the Antipas research team was unable to identify changes in fundamental physical constants.Nonetheless, a paper by Antipas et al. showing how certain fundamental physical constants are invariant was published in the scientific journal Physical Review Letters in July 2010.posted。

In this study, Antipas et al., in collaboration with a research team at Heinrich Heine University Düsseldorf, even if the electron mass changes, the fluctuation range is less than 1/100 trillion, and the fluctuation range of the iodine nucleus is 1/10 trillion. I found the following. Antipas points out that the variation of the fine-structure constant is also less than 1 part in 100 trillion.

Seeking unidentified “dark matter”

The research team was investigating fluctuations in fundamental physical constants becausedark matterwas to find Dark matter is a mysterious substance estimated to make up 85% of the universe.

In 1933, Swiss astrophysicist Fritz Zwicky observed a galaxy that seemed to be spinning at speeds impossible for visible matter. Normally, at that speed, gravity would tear the galaxy apart, like pancake batter being splattered with a hand mixer. Zwicky wondered if the galaxies were held together by an invisible substance now called “dark matter.”

Since then, researchers have observed plenty of evidence for the existence of dark matter. “We know from the gravity of dark matter that[near-Earth]dark matter is between one-third and three times as dense,” explains Julia Gerain of Brookhaven National Laboratory. Gehlein was not involved in her current paper. She said, “I just don’t know what dark matter is.”

One theory of dark matter in physics theory predicts that its interactions with electrons and other particles will cause changes in some fundamental physical constants. However, the research team was unable to detect any changes.

This allows particles with specific masses and specific properties to be ruled out as dark matter candidates. The results of this study are consistent with those of other experiments, says Gehlein.

A compact experiment carried out on a table

Antipus’ team was specifically looking for something called “ultralight dark matter.” Ultralight dark matter is a particle that weighs at least one trillionth of an electron.

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