Thermodynamic properties of mesoscopic systems

In last few decades mesoscopic physics has emerged as a prominent area of research and development. It promises to give rise to a new generation of electronic devices that work on quantum principles. Although these devices can revolutionize the electronic industry, have not been achieved yet as it is difficult to control their stability. We have shown that one can use evanescent modes to build stable quantum switches using a multichannel Aharonov-Bohm interferometer, where we proposed a new S matrix. Using A-B interferometer we explained magnetic induction generated by transport current. Quantum tunneling of an electron through a classically forbidden regime has no classical analogue. We analyzed a situation where electronic current under the barrier can be measured using evanescent modes. We showed unlike other proposed quantum devices such currents are not sensitive to changes in material parameters and thus the system can be used to build stable devices that work on magnetic properties. Capacitance of a system is self consistently determined by Coulomb interaction and this is no exception for quantum capacitance. We started from microscopic approach to many body physics and showed the analytical steps and approximations required to arrive at the concept of quantum capacitance.