Executive Summary : | Quantum machines are a combination of quantum mechanics and thermodynamics, with the working substance being quantum mechanical. Early studies focused on a few body systems, but studying many body quantum machines is expected to provide significant advantages. Many body interacting systems undergoing quantum phase transitions may show rich behavior due to critical phenomena. One commonly studied quantum machine is the quantum engine, which consists of a working medium (WM) undergoing operations to convert thermal energy absorbed from a hot reservoir into useful work. There are different types of engine cycles for a quantum engine, with the most common being the Otto cycle. In this cycle, the working medium is connected to hot and cold reservoirs or baths at temperatures $T_h$ and $T_c$ respectively, separated by a stroke consisting of unitary dynamics. Efficiency and power are characterized by efficiency and power. To improve efficiency, the unitary dynamics should be adiabatic, which would increase cycle time and decrease power. Scientists have been trying to develop techniques such as shortcuts to adiabaticity to increase power and efficiency. However, developing an easy-to-implement shortcut to adiabaticity is highly desirous. This proposal aims to explore techniques to improve efficiency and power without compromising simplicity. The study of how chaos in a working medium affects engine working is still an unexplored area. In addition to quantum engines, other quantum technologies include refrigerators, quantum batteries, quantum probes, and quantum transistors. This field has received attention due to development in experimental techniques that enable the realization of these proposed engines in the lab. |