Chintalpati Umashankar Shastry
Academic and research departments
Department of Physics, Faculty of Engineering and Physical Sciences.About
Biography
Chintalpati Umashankar Shastry is an Associate Intern under the supervision of Dr Andrea Rocco, in the department of physics at the University of Surrey. He completed his undergraduate degree in mechanical engineering from Motilal Nehru National Institute of Technology (Allahabad). Umashankar studied at University of Surrey to get Masters of Science in physics. His area of interest is in Quantum field theory and Open quantum system. Currently, he is working in the group of Dr Andrea Rocco to apply the renormalisation group approach to open quantum systems and obtain an exact renormalisation group equation in the Non-Markovian limit. In this project he is trying to use Wilson’s renormalization techniques to get an invariant model where the correction terms in the effective action of the system, generated due to the path integral of the environmental coordinate, can be calculated by the shell mode integration of the Wilsonian effective action. The project is still ongoing, and it is in its initial phase.
Areas of specialism
University roles and responsibilities
- Associate Intern
My qualifications
ResearchResearch interests
Quantum Field Theory (QFT), Open Quantum System.
Research projects
Renormalisation Group approach to open quantum systemsCurrently, I am working in the group of Dr Andrea Rocco to apply the renormalization group approach to open quantum systems and obtain an exact renormalisation group equation in the Non-Markovian limit. In this project I am trying to use Wilson’s renormalization techniques to get an invariant model where the correction terms in the effective action of the system, generated due to the path integral of the environmental coordinate, can be calculated by the shell mode integration of the Wilsonian effective action. The project is still ongoing, and it is in its initial phase.
Dirac EquationI did my MSc dissertation on solving the Dirac equation for hydrogen atom in finite basis expansion. This project was supervised by Dr Paul Stevenson. In this work, matrix representation of Dirac Hamiltonian was obtained in a finite set basis spinors. In principle any infinite basis set can be used to obtain a matrix representation of the Hamiltonian of the system, however, if the basis set are not kinetically balanced, then the so called spurious energy states fill the energy spectrum. Two methods were developed, namely basis expansion method and Variational method. In basis expansion method the inner product of kinetically balanced Dirac basis spinors were taken with Dirac Hamiltonian to get the matrix elements, while in the Variational method large component was expanded in terms of orthonormal basis functions while the small component was expanded in kinetically balanced basis functions. Both methods give rise to the spurious energy states, however, variational method shows less spurious states than basis expansion method for the given number of basis functions (or spinors in the case of basis expansion method). Variational method is slower and the convergence of largest positive energy eigenvalue to the theoretical ground state energy is slower than basis expansion method.
Research interests
Quantum Field Theory (QFT), Open Quantum System.
Research projects
Currently, I am working in the group of Dr Andrea Rocco to apply the renormalization group approach to open quantum systems and obtain an exact renormalisation group equation in the Non-Markovian limit. In this project I am trying to use Wilson’s renormalization techniques to get an invariant model where the correction terms in the effective action of the system, generated due to the path integral of the environmental coordinate, can be calculated by the shell mode integration of the Wilsonian effective action. The project is still ongoing, and it is in its initial phase.
I did my MSc dissertation on solving the Dirac equation for hydrogen atom in finite basis expansion. This project was supervised by Dr Paul Stevenson. In this work, matrix representation of Dirac Hamiltonian was obtained in a finite set basis spinors. In principle any infinite basis set can be used to obtain a matrix representation of the Hamiltonian of the system, however, if the basis set are not kinetically balanced, then the so called spurious energy states fill the energy spectrum. Two methods were developed, namely basis expansion method and Variational method. In basis expansion method the inner product of kinetically balanced Dirac basis spinors were taken with Dirac Hamiltonian to get the matrix elements, while in the Variational method large component was expanded in terms of orthonormal basis functions while the small component was expanded in kinetically balanced basis functions. Both methods give rise to the spurious energy states, however, variational method shows less spurious states than basis expansion method for the given number of basis functions (or spinors in the case of basis expansion method). Variational method is slower and the convergence of largest positive energy eigenvalue to the theoretical ground state energy is slower than basis expansion method.