scholarly journals Tuning equilibration of quantum Hall edge states in graphene – Role of crossed electric and magnetic fields

2016 ◽  
Vol 237-238 ◽  
pp. 59-63 ◽  
Author(s):  
Sudipta Dubey ◽  
Mandar M. Deshmukh
Keyword(s):  
Magnetic Fields ◽  
Quantum Hall ◽  
Edge States ◽  
Electric And Magnetic Fields

scholarly journals Dynamics of electric and magnetic fields in case of the urban environment

2021 ◽  
Vol 265 ◽  
pp. 02001
Author(s):  
Vladimir I. Sturman ◽  
Alyona N. Loginovskaya ◽  
Anastasiya A. Dolganova ◽  
Mihail V. Shirokov
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Fields ◽  
Transmission Lines ◽  
Indirect Effects ◽  
Temporal Dynamics ◽  
Weather Conditions ◽  
Line Frequency ◽  
Saint Petersburg ◽  
Electric And Magnetic Fields

This paper studies the temporal dynamics of power-line frequency electric and magnetic fields in Saint-Petersburg and environs. It is found that electromagnetic fields generated by high-voltage transmission lines (HVTL) constantly change, depending on their loading and weather conditions. The dependence on weather conditions involves both the direct effect of air electrical conductivity as a function of its humidity, and indirect effects including the dependence of energy consumption on temperature and also the correlations between meteorological characteristics. An attempt has been made to evaluate the role of influencing factors.

scholarly journals Quantum Hall–based superconducting interference device

2019 ◽  
Vol 5 (9) ◽  
pp. eaaw8693 ◽  
Author(s):  
Andrew Seredinski ◽  
Anne W. Draelos ◽  
Ethan G. Arnault ◽  
Ming-Tso Wei ◽  
Hengming Li ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Josephson Junction ◽  
Landau Level ◽  
Carrier Density ◽  
Filling Factor ◽  
Quantum Hall ◽  
Edge States ◽  
Highly Efficient ◽  
Wide Range

We present a study of a graphene-based Josephson junction with dedicated side gates carved from the same sheet of graphene as the junction itself. These side gates are highly efficient and allow us to modulate carrier density along either edge of the junction in a wide range. In particular, in magnetic fields in the 1- to 2-T range, we are able to populate the next Landau level, resulting in Hall plateaus with conductance that differs from the bulk filling factor. When counter-propagating quantum Hall edge states are introduced along either edge, we observe a supercurrent localized along that edge of the junction. Here, we study these supercurrents as a function of magnetic field and carrier density.

scholarly journals From Chern–Simons to Tomonaga–Luttinger

2018 ◽  
Vol 33 (02) ◽  
pp. 1850013 ◽  
Author(s):  
Nicola Maggiore
Keyword(s):  
Degrees Of Freedom ◽  
Quantum Hall ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Edge States ◽  
Fractional Quantum ◽  
Fractional Quantum Hall ◽  
Chern Simons ◽  
Weyl Fermion

A single-sided boundary is introduced in the three-dimensional Chern–Simons model. It is shown that only one boundary condition for the gauge fields is possible, which plays the twofold role of chirality condition and bosonization rule for the two-dimensional Weyl fermion describing the degrees of freedom of the edge states of the Fractional Quantum Hall Effect. The symmetry on the boundary is derived, which determines the effective two-dimensional action, whose equation of motion coincides with the continuity equation of the Tomonaga–Luttinger theory. The role of Lorentz symmetry and of discrete symmetries on the boundary is also discussed.

THEORETICAL ASPECTS OF QUANTUM HALL EFFECT AND TWO-DIMENSIONAL CFT

1992 ◽  
Vol 06 (11n12) ◽  
pp. 2217-2239 ◽  
Author(s):  
G. CRISTOFANO ◽  
G. MAIELLA ◽  
R. MUSTO ◽  
F. NICODEMI
Keyword(s):  
Quantum Hall ◽  
Coulomb Gas ◽  
Topological Order ◽  
Two Dimensional ◽  
Edge States ◽  
Conformal Field ◽  
Highest Weight ◽  
Finite Set ◽  
Magnetic Translation

A review of the QHE is presented where the emphasis is placed on the role of the magnetic translation group and of the related topological properties. After a presentation of general experimental and theoretical features we briefly summarize known results of two-dimensional Conformal Field Theory relevant for the QHE. Then we show how to evaluate groundstate wave functions on the plane and on the torus by the use of CFT techniques. In the latter case it is shown how for filling ν=1/m a consistent description is achieved by means of a finite set of Coulomb Gas Vertex Operators. They describe (fractional) charged particles with the associated quantized magnetic flux (“anyons"). Furthermore, from these vertices and relative highest weight states, one does find that the g.s.w.f. for the torus should be m-fold degenerate showing, also, the role of a new kind of long-range topological order recently advocated. Then we show that the presence of m sectors of edge states for a cylinder is strictly related to such a degeneracy, and their relation with a Kac-Moody algebra is discussed.

EDGE STATES AND TRAJECTORIES IN QUANTUM DOTS: PROBING THE QUANTUM-CLASSICAL TRANSITION

2007 ◽  
Vol 21 (08n09) ◽  
pp. 1278-1287
Author(s):  
D. K. FERRY ◽  
R. AKIS ◽  
J. P. BIRD
Keyword(s):  
Quantum Dot ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Oscillatory Behavior ◽  
Wave Functions ◽  
Edge States ◽  
Open Quantum ◽  
Pointer States ◽  
Classical Transition

Edge states have been a backbone of our understanding of the experimental basis of the quantum Hall effect for quite some time. Interestingly, this comprises a quantum system with well defined currents and particle trajectories. The role of trajectories in quantum mechanics has been a problematic question of interpretation for quite some time, and the open quantum dot is a natural system in which to probe this question. Contrary to early speculation, a set of well defined quantum states survives in the open quantum dot. These states are the pointer states and provide a transition into the classical states that can be found in these structures. These states provide resonances, which are observable as oscillatory behavior in the magnetoconductance of the dots. But, they have well defined current directions within the dots. Consequently, one expects trajectories to be a property of these states as well. As one crosses from the low to the high field regime, quite steady trajectories and consequent wave functions can easily be identified and examined. In this talk, we review the current understanding and the support for the decoherence theory.

scholarly journals BAND COLLAPSE AND THE QUANTUM HALL EFFECT IN GRAPHENE

2006 ◽  
Vol 20 (22) ◽  
pp. 3257-3278 ◽  
Author(s):  
B. ANDREI BERNEVIG ◽  
TAYLOR L. HUGHES ◽  
SHOU-CHENG ZHANG ◽  
HAN-DONG CHEN ◽  
CONGJUN WU
Keyword(s):  
Magnetic Fields ◽  
Quantum Hall Effect ◽  
Hexagonal Lattice ◽  
Quantum Hall ◽  
Exact Diagonalization ◽  
Edge States ◽  
Hall Conductance ◽  
Dirac Spectrum ◽  
Lattice Effects ◽  
Fermion Systems

The recent quantum Hall experiments in graphene have confirmed the theoretically well-understood picture of the quantum Hall (QH) conductance in fermion systems with continuum Dirac spectrum. In this paper we take into account the lattice and perform an exact diagonalization of the Landau problem on the hexagonal lattice. At very large magnetic fields the Dirac argument fails completely and the Hall conductance, given by the number of edge states present in the gaps of the spectrum, is dominated by lattice effects. As the field is lowered, the experimentally observed situation is recovered through a phenomenon which we call band collapse. As a corollary, for low magnetic fields, graphene will exhibit two qualitatively different QHE's: at low filling, the QHE will be dominated by the "relativistic" Dirac spectrum and the Hall conductance will be odd-integer; above a certain filling, the QHE will be dominated by a non-relativistic spectrum, and the Hall conductance will span all integers, even and odd.

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