Výskumníci univerzity v Osake ukazujú relativistickú kontrakciu elektrického poľa generovaného rýchlo sa pohybujúcimi nabitými časticami, ako to predpovedá Einsteinova teória, čo by mohlo pomôcť zlepšiť výskum fyziky častíc a žiarenia.

Pred viac ako storočím jeden z najznámejších moderných fyzikov Albert Einstein navrhol prelomovú teóriu špeciálnej relativity. Väčšina všetkého, čo o vesmíre vieme, je založená na tejto teórii, avšak časť z toho ešte nebola experimentálne dokázaná. učenci, ktorí Univerzita v Osake Inštitút laserového inžinierstva prvýkrát použil ultrarýchle elektrooptické merania na vizualizáciu kontrakcie elektrického poľa obklopujúceho elektrónový lúč pohybujúci sa rýchlosťou blízkou rýchlosti svetla a na demonštráciu procesu generovania.

Podľa Einsteinovej teórie špeciálnej relativity je potrebné použiť „Lorentzovu transformáciu“, ktorá kombinuje súradnice priestoru a času, aby bolo možné opísať pohyb objektov prechádzajúcich okolo pozorovateľa rýchlosťou blížiacou sa rýchlosti svetla. Dokázal vysvetliť, ako tieto transformácie viedli k samokonzistentným rovniciam elektrických a magnetických polí.

Zatiaľ čo rôzne účinky relativity boli mnohokrát dokázané s veľmi vysokou mierou experimentovania[{“ attribute=““>accuracy, there are still parts of relativity that have yet to be revealed in experiments. Ironically, one of these is the contraction of the electric field, which is represented as a special relativity phenomenon in electromagnetism.

Illustration of the formation process of the planar electric field contraction that accompanies the propagation of a near-light-speed electron beam (shown as an ellipse in the figure). Credit: Masato Ota, Makoto Nakajima

Now, the research team at Osaka University has demonstrated this effect experimentally for the first time. They accomplished this feat by measuring the profile of the Coulomb field in space and time around a high-energy electron beam generated by a linear particle accelerator. Using ultrafast electro-optic sampling, they were able to record the electric field with extremely high temporal resolution.

It has been reported that the Lorentz transformations of time and space as well as those of energy and momentum were demonstrated by time dilation experiments and rest mass energy experiments, respectively. Here, the team looked at a similar relativistic effect called electric-field contraction, which corresponds to the Lorentz transformation of electromagnetic potentials.

“We visualized the contraction of an electric field around an electron beam propagating close to the speed of light,” says Professor Makoto Nakajima, the project leader. In addition, the team observed the process of electric-field contraction right after the electron beam passed through a metal boundary.

When developing the theory of relativity, it is said that Einstein used thought experiments to imagine what it would be like to ride on a wave of light. “There is something poetic about demonstrating the relativistic effect of electric fields more than 100 years after Einstein predicted it,” says Professor Nakajima. “Electric fields were a crucial element in the formation of the theory of relativity in the first place.”

This research, with observations matching closely to Einstein’s predictions of special relativity in electromagnetism, can serve as a platform for measurements of energetic particle beams and other experiments in high-energy physics.

Reference: “Ultrafast visualization of an electric field under the Lorentz transformation” by Masato Ota, Koichi Kan, Soichiro Komada, Youwei Wang, Verdad C. Agulto, Valynn Katrine Mag-usara, Yasunobu Arikawa, Makoto R. Asakawa, Youichi Sakawa, Tatsunosuke Matsui and Makoto Nakajima, 20 October 2022, Nature Physics.
DOI: 10.1038/s41567-022-01767-w

The study was funded by the Japan Society for the Promotion of Science and the NIFS Collaborative Research Program.