Cooled to nano-Kelvin temperatures, Bose-Einstein condensates acquire macroscopic quantum properties. Observable in experiments, quantum gases give direct access to quantum physics. Be it the components of novel quantum technologies, or as simulators of condensed matter systems, it is of immense value to know the role by quantum and thermal fluctuations to a fine detail. We explore the equilibrium and out-of-equilibrium properties of spinor Bose-Einstein condensates at finite temperatures.

There have been a lot of interest in the miniaturization of the thermodynamic heat engines and pumps to the quantum mechanical systems and understand the applicability and modification in the laws of classical thermodynamics to these quantum thermodynamic systems. The optimal implementation and investigation of such devices with ultracold neutral atoms in quantum-gas microscopes offers a fruitful platform for the experiments. The development of theoretical design and their experimentally realistic model using Bose-Einstein condensates of dilute atomic gases are of great importance in development of new quantum technologies. Apart from advancing the emerging field of quantum thermodynamics, we aim to illustrate possibilities in discovering useful quantum machines to cool ultracold quantum gases beyond the well-known techniques of evaporative and laser cooling.

In QDs the energy of an absorbed photon can via multiple exciton generation (MEG) be broken down into many electron-hole pairs thereby increasing the photocurrent. Alternatively, hot electron transfer can use the extra energy providing higher photovoltage. Both of these processes are capable of improving the solar cell efficiency beyond the Shockley-Queisser limit. In order to make use of the effects, the processes have to be followed by efficient charge stabilization with minimal back recombination. It is also vital to efficiently fill the holes left in QDs after electron injection. The purpose of the current project is to carry out a thorough study of the dynamic processes in the material to optimize the key components of QD solar cells (QDSC).

We study the structure and ionization/scattering dynamics of atomic systems using theoretical and computational methods. These atomic systems can be simple atoms or exotic systems such as atoms trapped in a fullerene (endohedral systems) or it can be a collection of atoms together (clusters). We explore these systems mainly with a fundamental point of view to get a rigorous understanding of the electron-electron interactions, relativistic effects and also to know how the properties of atomic systems get modified by the presence of an external cage. We also study the dynamics of ionization in the time domain (atto-second spectroscopy) to get deeper insights to the ionization process. The photoelectron/scattered electrons are the information carriers of the target. By studying them systematically, we can extract all the required information. A deep knowledge on ionization and scattering processes play an important role in nano-science, developing quantum technologies, plasmonics and xuv lithography etc.