24,791 research outputs found
Non-Linear Effects in Resonant Tunneling; Bistabilities and Self-Sustained Oscillating Currents
We study non-linear phenomena in double barrier heterostructures. Systems in
3D under the effect of an external magnetic field along the current and 1D
systems are analyzed. Non-linearities are reflected in the I-V characteristic
curve as bistabilities, instabilities and time dependent oscillations of the
currents. The nature of the non-linear behavior depends upon the parameters
that define the system.Comment: 3 pages, 2 figures, accepted for publication in Superlattices and
Microstructure
Regular black holes in gravity
In this work, we study the possibility of generalizing solutions of regular
black holes with an electric charge, constructed in general relativity, for the
theory, where is the Gauss-Bonnet invariant. This type of solution
arises due to the coupling between gravitational theory and nonlinear
electrodynamics. We construct the formalism in terms of a mass function and it
results in different gravitational and electromagnetic theories for which mass
function. The electric field of these solutions are always regular and the
strong energy condition is violated in some region inside the event horizon.
For some solutions, we get an analytical form for the function. Imposing
the limit of some constant going to zero in the function we recovered
the linear case, making the general relativity a particular case.Comment: 22 pages, 25 figures.Version published in EPJ
Lorentz-violating nonminimal coupling contributions in mesonic hydrogen atoms and generation of photon higher-order derivative terms
We have studied the contributions of Lorentz-violating CPT-odd and CPT-even
nonminimal couplings to the energy spectrum of the mesonic hydrogen and the
higher-order radiative corrections to the effective action of the photon sector
of a Lorentz-violating version of the scalar electrodynamics. By considering
the complex scalar field describes charged mesons (pion or kaon), the
non-relativistic limit of the model allows to attain upper-bounds by analyzing
its contribution to the mesonic hydrogen energy. By using the experimental data
for the strong correction shift and the pure QED transitions , the best upper-bound for the CPT-odd coupling is
and for the CPT-even one is
. Besides, the CPT-odd radiative correction to the
photon action is a dimension-5 operator which looks like a higher-order
Carroll-Field-Jackiw term. The CPT-even radiative contribution to the photon
effective action is a dimension-6 operator which would be a higher-order
derivative version of the minimal CPT-even term of the standard model
extension
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