Indian Scientists Unlock Atomic Interactions Paving the Way for Next-Generation Quantum Devices

New Delhi, 22 September 2025: In a significant breakthrough for Indian quantum research, scientists have demonstrated how atoms cease to behave as independent particles when pushed into extremely high-energy states. At these energy levels, the atoms interact so strongly that their response to light becomes broadened and distorted, marking the first global observation of interaction-driven distortions in Rydberg atomic signals. This discovery could play a crucial role in the development of advanced quantum computers, sensors, and communication devices.

Rydberg atoms, which are atoms with electrons excited to very high energy levels, expand dramatically in size and become highly sensitive to their environment. While this sensitivity is central to their applications in quantum technologies, it also makes them difficult to control. A research team from the Raman Research Institute (RRI), under the Department of Science and Technology, cooled rubidium atoms to near absolute zero and trapped them using lasers and magnetic fields. By exciting these atoms into Rydberg states, the scientists observed the expected Autler–Townes splitting patterns at lower energy levels. However, when atoms were pushed beyond the 100th energy level, these patterns blurred and distorted, signaling that the atoms were interacting collectively rather than individually.

“This distortion is not an error but evidence that atoms begin communicating and responding as a collective,” said Prof. Sanjukta Roy, who led the experiment alongside PhD students Silpa B S and Shovan K Barik. Theoretical modelling was provided by Prof. Rejish Nath’s team at IISER Pune. The team used a highly sensitive detection system capable of spotting even a few photons, enabling the study of Rydberg atoms at unprecedented energy levels.

This discovery provides critical insights into the transition from isolated atoms to entangled atomic communities, offering a roadmap for designing next-generation quantum devices. By exploring how and when atoms interact, Indian researchers have placed themselves at the forefront of global quantum science, opening new avenues for quantum computing, sensing, and communication technologies.