CHIRAL BOSON, CHIRAL VACUUM AND EDGE STATES IN THE FRACTIONAL QUANTUM HALL EFFECT

1994 ◽  
Vol 09 (07) ◽  
pp. 1181-1195 ◽  
Author(s):  
YUN SOO MYUNG
Keyword(s):  
Landau Level ◽  
Quantum Hall ◽  
Edge State ◽  
Harmonic Oscillators ◽  
Edge States ◽  
Many Body ◽  
Fractional Quantum ◽  
Fractional Quantum Hall ◽  
Lowest Landau Level ◽  
Boson Theory

By performing the Gupta–Bleuler quantization of a chiral boson, we obtain the chiral constraints, which correspond to the lowest Landau level conditions. From these, the chiral vacuum is defined as the vacuum of admixtures of many-harmonic oscillators. We construct the wave function for edge states of a droplet of incompressible quantum Hall fluid, by solving Schrödinger's equation on the basis of the chiral vacuum. This bosonic function can describe the collective edge modes, which are fundamentally a many-body effect of fermions at the lowest Landau level. In detail, the neutral edge state of FQHE is described by the α = 1 chiral boson theory. The charged edge states are described by the α ≠ 1 chiral boson theory.

scholarly journals Electron-hole asymmetric integer and fractional quantum Hall effect in bilayer graphene

Science ◽  
2014 ◽  
Vol 345 (6192) ◽  
pp. 55-57 ◽  
Author(s):  
A. Kou ◽  
B. E. Feldman ◽  
A. J. Levin ◽  
B. I. Halperin ◽  
K. Watanabe ◽  
...  
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Bilayer Graphene ◽  
Fractional Quantum Hall Effect ◽  
Many Body ◽  
Electron Hole ◽  
Fractional Quantum ◽  
Fractional Quantum Hall ◽  
Lowest Landau Level

The nature of fractional quantum Hall (FQH) states is determined by the interplay between the Coulomb interaction and the symmetries of the system. The distinct combination of spin, valley, and orbital degeneracies in bilayer graphene is predicted to produce an unusual and tunable sequence of FQH states. Here, we present local electronic compressibility measurements of the FQH effect in the lowest Landau level of bilayer graphene. We observe incompressible FQH states at filling factors ν = 2p + 2/3, with hints of additional states appearing at ν = 2p + 3/5, where p = –2, –1, 0, and 1. This sequence breaks particle-hole symmetry and obeys a ν → ν + 2 symmetry, which highlights the importance of the orbital degeneracy for many-body states in bilayer graphene.

THE CHIRAL BOSON THEORY AND EDGE STATES IN THE QUANTUM HALL EFFECT

1993 ◽  
Vol 08 (14) ◽  
pp. 1297-1303 ◽  
Author(s):  
YUN SOO MYUNG
Keyword(s):  
Hall Effect ◽  
Landau Level ◽  
Quantum Hall Effect ◽  
Condensed Matter ◽  
Quantum Hall ◽  
Electron System ◽  
Wave Functions ◽  
Edge States ◽  
Lowest Landau Level ◽  
Boson Theory

We construct the wave functions for the edge states of a droplet of quantum Hall effect by performing the Gupta-Bleuler quantization of a chiral boson. These wave functions describe the chiral edge states of a many-electron system in the lowest Landau level. This demonstrates a crucial connection between the particle and condensed matter physics.

scholarly journals Composite Fermions in the Hilbert Space of the Lowest Electronic Landau Level

1997 ◽  
Vol 11 (22) ◽  
pp. 2621-2660 ◽  
Author(s):  
J. K. Jain ◽  
R. K. Kamilla
Keyword(s):  
Landau Level ◽  
Ground State ◽  
Quantum Hall ◽  
Monte Carlo Study ◽  
Composite Fermions ◽  
Composite Fermion ◽  
Fractional Quantum ◽  
Fractional Quantum Hall ◽  
Lowest Landau Level ◽  
Standard Manner

Single particle basis functions for composite fermions are obtained from which many-composite fermion states confined to the lowest electronic Landau level can be constructed in the standard manner, i.e. by building Slater determinants. This representation enables a Monte Carlo study of systems containing a large number of composite fermions, yielding new quantitative and qualitative information. The ground state energy and the gaps to charged and neutral excitations are computed for a number of fractional quantum Hall effect (FQHE) states, earlier off-limits to a quantitative investigation. The ground state energies are estimated to be accurate to ~0.1% and the gaps at the level of a few percent. It is also shown that at Landau level fillings smaller than or equal to 1/9 the FQHE is unstable to a spontaneous creation of excitons of composite fermions. In addition, this approach provides new conceptual insight into the structure of the composite fermion wave functions, resolving in the affirmative the question of whether it is possible to motivate the composite fermion theory entirely within the lowest Landau level, without appealing to higher Landau levels.

scholarly journals On the Constraint Equation for the Lowest Landau Level in Fractional Quantum Hall System

1991 ◽  
Vol 05 (10) ◽  
pp. 1715-1724 ◽  
Author(s):  
Dong-Ning Sheng ◽  
Zhao-Bin Su ◽  
B. Sakita
Keyword(s):  
Field Theory ◽  
Landau Level ◽  
Quantum Hall ◽  
Constraint Equation ◽  
Wave Functions ◽  
Generic Properties ◽  
Fractional Quantum ◽  
Fractional Quantum Hall ◽  
Lowest Landau Level ◽  
Quantum Hall System

In the framework of collective field theory, We apply the Chern-Simon field theory treatment to the constraint equation for the lowest Landau level to investigate the generic properties for the quasi-particles of the FQH system. It shows a transparent connection to the Laughlin's wave functions. If we take an average over the wave functional for the constraint equation, the resulted equation can be interpreted as the vortex equation for the fractionally charged quasi-particles. Introducing a generalized ρ (density)-ϑ (phase) transformation, not only the fractional statistics and the hierarchy scheme can be drawn from the constraint equation, it also gives rise an interesting picture that vortices condense as a Halperin like wave fuction on a Laughlin like background condensate of ν=1/m.

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