3 research outputs found
Quantum Wire Network with Magnetic Flux
The charge transport and the noise of a quantum wire network, made of three
semi-infinite external leads attached to a ring crossed by a magnetic flux, are
investigated. The system is driven away from equilibrium by connecting the
external leads to heat reservoirs with different temperatures and/or chemical
potentials. The properties of the exact scattering matrix of this configuration
as a function of the momentum, the magnetic flux and the transmission along the
ring are explored. We derive the conductance and the noise, describing in
detail the role of the magnetic flux. In the case of weak coupling between the
ring and the reservoirs, a resonant tunneling effect is observed. We also
discover that a non-zero magnetic flux has a strong impact on the usual
Johnson-Nyquist law for the pure thermal noise at small temperatures.Comment: LaTex, 6 pages, 6 figures, improved discussion of the impact of the
magnetic flux on the pure thermal nois
Network Models: Action formulation
We develop a technique to formulate quantum field theory on arbitrary
network, based on different, randomly disposed sets of scattering's. We define
R-matrix of the whole network as a product of R-matrices attached to each of
scattering nods. Then an action for a network in terms of fermionic fields is
formulated, which allows to calculate the transition amplitudes as their Green
functions. On so-called bubble and triangle diagrams it is shown that the
method produces the same results as the one which uses the generalized star
product. The approach allows to extend network models by including
multiparticle interactions at the scattering nods.Comment: 27 pages, 9 figure