Study of Degeneracy Pressure in White Dwarfs using Quantum Field Theory

Mandal, Susobhan (2017) Study of Degeneracy Pressure in White Dwarfs using Quantum Field Theory. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Susobhan Mandal (12MS085)) SM_12MS085.pdf - Submitted Version Restricted to Repository staff only Download (786kB)

Abstract

In this thesis, we have studied the degeneracy pressure of White Dwarf system using techniques of Quantum Field Theory. In particular, we have cal- culated the correction to degeneracy pressure due to electro-dynamical interac- tions using perturbation techniques for both in non-relativistic and relativistic domain. This includes interactions among the electrons themselves and between the electrons and helium ions. Subsequently, we have found out the modified mass-radius equation and the corresponding Chandrasekhar mass limit. Using this calculation we are able to show that the Chandrasekhar limit is stable under the perturbation due to electro-dynamical interactions, since it changes the value of the Chandrasekhar limit by .01% in Yukawa-interaction and .02% in Quantum Electrodynamics (QED) like theory. In the second part, we have pointed out the singularity arising at Chandrasekhar limit and inconsistencies with General Relativity by showing Toleman-Oppenheimer- Volkoff (TOV) equations. White-Dwarf is one of the simplest possible strongly gravitating object where we can study Quantum Field Theory in curved space- time, phase-diagram of densed matter etc. It is also one of the simplest experi- mentally observable system unlike black holes or other compact objects, which can confront many predictions about the mentioned topics. Our work actually shows that under QED like interactions, predictions made by Chandrasekhar is not changed significantly.

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