Research Projects

Many aspects of contemporary physics rely on the knowledge of the basic properties of the atomic nucleus. However, a fundamental theory for understanding the structure and decay of nuclei remains as elusive as the exact form of the nuclear force. Theoretical nuclear physics is envisaged through several models constructed mostly in a phenomenological way. With the nucleus being a complex many-body system, the nuclear models are not so versatile due to the strong dependence on the parameters, which is generic for many body theories. Most nuclear models agree well while explaining nuclei for which experimental information is known. With a wealth of data available in several domains of nuclear physics, it is often feasible to validate the models representing the nature of the nuclear forces. This validation can be robust if the nuclear models apply to various domains of nuclear physics, including the extremes of isospin, density, temperature (T) and spin (I). The extremes of isospin can be accessed through the nuclei far from stability and as an extreme case the matter in neutron stars. Exploring the neutron matter inside neutron stars provides us with a testing ground to study the isospin as well as the density dependence of the nuclear force. The high-density regime can also be probed through heavy-ion collisions at intermediate and high energies. Low-density nuclear matter can be probed by studying the density oscillations. The developments in the nuclear models have reached a good level of versatility so that using a single model and a unique set of parameters one can explain the ground state of nuclei throughout the nuclear chart, infinite matter at higher densities and the neutron stars, with a commendable level of accuracy in all the cases. Nuclei at high excitation energies are not accessible by discrete gamma-ray spectroscopy and other conventional techniques. In such cases, giant dipole resonances (GDR) have been proven to be unique and effective probes. As the system gets excited to higher energies, the lifetime of the system decreases and the compound nucleus does not get enough time to equilibrate. In these cases, the GDR emission reflects the effect of different time scales relevant to this process. Giant resonances (GR) generally are small amplitude, high frequency, simple, collective modes of excitations in nuclei. Among the various possible modes of the GR, the most dominant mode is the isovector giant dipole resonance which is commonly termed GDR. The most important experimental observable for GDR is the cross-section as a function of the photon energy, from which one can extract the centroid energies and the GDR width. These observables could effectively reflect the structure of the nuclear state on which GDR is built. My present research will be carried forward to new regimes with state-of-the-art techniques in the proposed plan.