Unlocking the Secrets of Metastable States in Atomic Nuclei

Editorial / September 30, 2025

In the complex world of nuclear physics, where matter is probed at its most fundamental level, Prof. Sujit Tandel, Senior Professor at the School of Natural Sciences, Shiv Nadar Institution of Eminence, has been steadily working to advance our understanding of some of the most intriguing states of matter—metastable states in atomic nuclei.

These long-lived excited states, also known as nuclear isomers, are not only windows into the mechanics of what goes on inside an atom’s nucleus, but also hold immense promise for real-world applications, from medical imaging to futuristic batteries and clocks.

At the heart of his research lies one of nature’s most enigmatic interactions: the strong nuclear force. This fundamental force binds protons and neutrons together inside every nucleus, yet remains inadequately understood. An ‘excited’ nucleus has more energy than its stable ‘ground state’. The excess energy makes it unstable, and it releases the energy quickly to return to the stable ground state. However, this is not always a super quick phenomenon.

Prof. Tandel explains, “Strong nuclear interactions are not well understood. Most excited nuclear states exist for a trillionth of a second, but these long-lived states can exist for as long as seconds, minutes, or in rare cases, even years.”

This endurance of metastable states allows researchers to observe and harness them in ways unfeasible with shorter-lived states—something that has always interested Prof. Tandel.

By examining the peculiar lifetimes and decay modes of isomers, Prof. Tandel and his team extract rare insights into these quantum wave functions. Unpacking these patterns has even led his group to discover ‘extreme isomers’: states with exceptionally high excitation energies, angular momentum, or lifetimes that stand apart from all others.

Another one of Prof. Tandel’s research areas is nuclear isomers in superheavy elements (elements in the periodic table well beyond Uranium, with atomic numbers 92 and above), which are synthesized in laboratories and extend the periodic table to atomic number 118. He recalls a striking ‘Eureka!’ moment: while working on isotopes of Nobelium, a superheavy element (atomic number 102), he realised that studying the properties of these long-lived states could help predict which superheavy elements might be less difficult to produce and identify in the lab.

That insight opened a new frontier, with dozens of global studies building upon this, shaping how researchers explore the boundaries of the periodic table and superheavy elements.

However, such breakthroughs do not come easily. One of the biggest challenges is bringing together expertise, equipment, and manpower for the successful execution of experiments. The complex experiments demand state-of-the-art radiation detectors, cutting-edge instrumentation, advanced measurement techniques and signal processing, as well as years of painstaking preparation. “It is like picking a needle out of a haystack,” Prof. Tandel says, reflecting on the challenges of isolating the information they want from large volumes of data.

He further notes that while nuclear physicists have developed a fair understanding of stable nuclei and those lacking neutrons, neutron-rich nuclei remain difficult to produce and study. These nuclei hold answers to many questions, including how the heaviest elements in the universe are formed. They are created through rapid neutron capture processes in stellar environments (such as stars like our sun), but replicating and investigating that in the lab remains a challenge. “Filling this gap and uncovering the structure and behaviour of neutron-rich nuclei is central to advancing both fundamental physics and our understanding of heavy elements in the cosmos”, explains Prof. Tandel.

Today, nuclear isomers already play important roles in medicine and could enable powerful new technologies in the near future. Technetium-99m, for example, is an isomer used in millions of medical imaging procedures worldwide each year. A future prospect is the nuclear clock, which promises extremely high-precision tracking in applications where minuscule-level timekeeping is required. Another ambitious vision is the nuclear battery, which can harness the immense energy stored in nuclear isomers—often millions of times more than chemical reactions—to pack unprecedented power into small volumes.

For Prof. Tandel, research and mentorship go hand in hand. His message to aspiring nuclear physicists is both candid and practical: “This is a challenging field and it is intellectually stimulating and satisfying. But the transferable skills and discipline you develop, from physics to instrumentation and electronics to computer programming, will serve you wherever you go.” He adds that global investment in nuclear physics will continue as countries seek to meet energy demands and advance technologies, ensuring opportunities in both research and applied domains. “There is a lot happening in this field, and it addresses one of the most basic requirements of the human race: energy, with the practically limitless and clean nuclear fusion energy on the horizon.”

He also explains how today’s nuclear research could inspire tomorrow’s transformative technologies. A shining example is Rudolf Mössbauer, whose work in nuclear physics at a young age led to the discovery of the Mössbauer effect, creating an entirely new research area, now widely used in physics, chemistry, and biology.

As he looks ahead, Prof. Tandel remains energised by the mysteries yet unsolved, gaps currently unaddressed, and the applications waiting to be realised. His work stands at the crossroads of fundamental physics and societal impact, pushing the boundaries of existing knowledge while opening doors to future innovation.

We look forward to his next discovery and the real-life innovations that it may bring!