Are JJ Thomson's ideas used today?

Yes, J.J. Thomson's ideas, particularly his discovery of the electron and the concept of the atomic model, are foundational to modern physics and chemistry. His work laid the groundwork for understanding atomic structure and the behavior of subatomic particles, which is essential in fields like quantum mechanics, materials science, and electronics. Today, concepts related to electrons are crucial in technologies such as semiconductors and various forms of spectroscopy. Thus, his contributions continue to influence both theoretical research and practical applications.