Perturbative Improvements and Exotic Excitations of Composite Fermions
Open Access
- Author:
- Peterson, Michael Ronald
- Graduate Program:
- Physics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 15, 2005
- Committee Members:
- Jainendra Jain, Committee Chair/Co-Chair
Stephane Coutu, Committee Member
Jorge Osvaldo Sofo, Committee Member
John V Badding, Committee Member
Jayanth R Banavar, Committee Member - Keywords:
- condensed matter physics
fractional quantum Hall effect
composite fermions - Abstract:
- Systems containing many strongly correlated particles are at the frontier of physics. Many-particle physics is challenging in that many of the usual tools of theoretical physics are not applicable and new ones are required. Further, many of the relevant experimental systems, where the physics is explored, are technologically important and a solid understanding of the physical systems would surely have an impact on future technologies. The system of the fractional quantum Hall effect is the quintessential example of a many-particle strongly correlated electron system. The composite fermion theory of the fractional quantum Hall effect provides a mapping between the strongly interacting electrons and an emergent system of new weakly interacting quasiparticles called composite fermions. The composite fermion theory, thus, unifies the fractional quantum Hall effect with the well understood integral quantum Hall effect. The composite fermion theory allows a conventional single particle description to be utilized. This thesis concerns composite fermions excitations. (i)Excitations are used in a perturbative fashion to obtain new improved values of the ground state and excited state energies for many different fractional quantum Hall systems. These results shed light on the possible phase transition between an electron liquid and solid in the low filling factor regime. (ii)New types of composite fermion excitations are introduced where the integrity of the composite fermion does not remain intact. These new excitation modes provide an explanation for recent experimental results. (iii) An electron or hole excitation is found to exist in the fractional quantum Hall fluid as a long-lived bound state of composite fermion particles or holes. It is suggested that the existence of these complex composite fermion bound states will have observable consequences in tunneling experiments.