Mais de um século depois de sua primeira aparição, os cientistas concluíram o dever de casa de Einstein sobre a relatividade restrita no eletromagnetismo.
Pesquisadores da Universidade de Osaka mostram a contração relativística de um campo elétrico gerado por partículas carregadas em movimento rápido, conforme previsto pela teoria de Einstein, o que poderia ajudar a melhorar a pesquisa em física de partículas e radiação.
Mais de um século atrás, um dos mais famosos físicos modernos, Albert Einstein, propôs a revolucionária teoria da relatividade restrita. A maior parte de tudo o que sabemos sobre o universo é baseado nessa teoria, no entanto, parte dela ainda não foi comprovada experimentalmente. estudiosos que Universidade de Osaka O Institute of Laser Engineering usou medições fotoelétricas ultrarrápidas pela primeira vez para visualizar a contração do campo elétrico em torno de um feixe de elétrons viajando próximo à velocidade da luz e para demonstrar o processo de geração.
De acordo com a teoria da relatividade especial de Einstein, deve-se usar a “transformada de Lorentz”, que combina as coordenadas do espaço e do tempo para descrever o movimento dos objetos que passam por um observador a uma velocidade que se aproxima da velocidade da luz. Ele foi capaz de explicar como essas transformações levaram a equações autoconsistentes de campos elétricos e magnéticos.
Embora os vários efeitos da relatividade tenham sido comprovados muitas vezes com um alto grau de experimentação[{” 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.