Prof. Jainendra Jain

From: Pennsylvania State University

Presentation Title: Composite fermion Fermi sea: Is the glass half empty or half full? 

When: 10:00 on Oct. 19th, 2015 

Where: 502 Conference Hall, CHMFL 

Host: Prof. Mingliang Tian 

Abstract 

Composite fermions are emergent topological particles that arise as a result of interaction between electrons confined to two dimensions and exposed to a strong magnetic field. They were postulated to explain the phenomenon of the fractional quantum Hall effect as the integer quantum Hall effect of composite fermions. After a brief pedagogical introduction, I will come to some recent puzzles regarding a remarkable manifestation of composite fermions at the half filled Landau level, namely their Fermi sea, which arises as a non-perturbative consequence of emergent gauge fields in a system where there was no Fermi sea to begin with. An intuitive picture suggests two equally plausible Fermi seas that appear to be topologically distinct and occupy different areas. We provide theoretical evidence that these are in fact dual descriptions of the same state. We calculate the Fermi wave vector in a particle- hole symmetric theory, and find our results to be generally consistent with the experimental results of Kamburov et al. [Phys. Rev. Lett. 113, 196801 (2014)]. Most remarkably, we predict that the area of the CF Fermi sea slightly violates the cherished Luttinger's area rule of Fermi liquids. This work [A. C. Balram and C. Toke arXiv:1506.02747 (2015) and Phys. Rev. Lett. in press] was supported by the US Department of Energy.