14 research outputs found
Wave Propagation Theory Denies the Big Bang
Problems related to Big Bang because of the Doppler interpretation of cosmological redshift have not been resolved up to recent years. The âtired lightâ theory proposes an energy loss model that has its own limitations. Chen in 2020 and 2021 proposed to treat light propagation through the space just as a field problem involving electromagnetic waves and governed by the well-known nonlinear Schrödinger (NLS) equation. The space is not a vacuum and is sparsely populated with matters. Electromagnetic waves traveling through the space will undergo changes as predicted by the NLS equation involving a linear dispersion and a nonlinear self-phase focusing terms. Using the cosmological principle, the coefficients associated with these terms could be constants but extremely small in value. Special numerical methods have been developed and could be used to find both bright and dark soliton-like solutions for the NLS equation that are stable and could travel through the extremely long distance involved. These solutions clearly show the redshift is linearly proportional to distance traveled for both bright and dark solitons. The conclusion is that redshift (and blue shift) is an innate nature of light traveling through the space
Stability of temporal solitons in uniform and "managed" quadratic nonlinear media with opposite group-velocity dispersions at fundamental and second harmonics
The problem of the stability of solitons in second-harmonic-generating media
with normal group-velocity dispersion (GVD) in the second-harmonic (SH) field,
which is generic to available chi^(2) materials, is revisited. Using an
iterative numerical scheme to construct stationary soliton solutions, and
direct simulations to test their stability, we identify a full
soliton-stability range in the space of the system's parameters, including the
coefficient of the group-velocity-mismatch (GVM). The soliton stability is
limited by an abrupt onset of growth of tails in the SH component, the relevant
stability region being defined as that in which the energy loss to the tail
generation is negligible under experimentally relevant conditions. We
demonstrate that the stability domain can be readily expanded with the help of
two "management" techniques (spatially periodic compensation of destabilizing
effects) - the dispersion management (DM) and GVM management. In comparison
with their counterparts in optical fibers, DM solitons in the chi^(2) medium
feature very weak intrinsic oscillations.Comment: Optics Communications, in pres
Single- and multi-peak solitons in two-component models of metamaterials and photonic crystals
We report results of the study of solitons in a system of two
nonlinear-Schrodinger (NLS) equations coupled by the XPM interaction, which
models the co-propagation of two waves in metamaterials(MMs). The same model
applies to photonic crystals (PCs), as well as to ordinary optical fibers,
close to the zero-dispersion point. A peculiarity of the system is a small
positive or negative value of the relative group-velocity dispersion (GVD)
coefficient in one equation, assuming that the dispersion is anomalous in the
other. In contrast to earlier studied systems of nonlinearly coupled NLS
equations with equal GVD coefficients, which generate only simple single-peak
solitons, the present model gives rise to families of solitons with complex
shapes, which feature extended oscillatory tails and/or a double-peak structure
at the center. Regions of existence are identified for single- and double-peak
bimodal solitons, demonstrating a broad bistability in the system. Behind the
existence border, they degenerate into single-component solutions. Direct
simulations demonstrate stability of the solitons in the entire existence
regions. Effects of the group-velocity mismatch (GVM) and optical loss are
considered too. It is demonstrated that the solitons can be stabilized against
the GVM by means of the respective "management" scheme. Under the action of the
loss, complex shapes of the solitons degenerate into simple ones, but periodic
compensation of the loss supports the complexity.Comment: Optics Communications, in press (Special Issue on Nonlinear
Metamaterials
Epithelial reticulon 4B (Nogo-B) is an endogenous regulator of Th2-driven lung inflammation
The reticulon protein Nogo-B is highly expressed in the lungs, and its loss augments lung inflammation in part as a result of decreased expression of the antiinflammatory protein PLUNC
Geochemical Characteristics of Wuyang Siliceous Rocks in the Southern Margin of North China Craton and its Constraint on the Formation Environment of BIF of Tieshanmiao Formation
Measurement of proton electromagnetic form factors in the time-like region using initial state radiation at BESIII
The electromagnetic process is studied with the initial-state-radiation technique using 7.5 fbâ1 of data collected by the BESIII experiment at seven energy points from 3.773 to 4.600 GeV. The Born cross section and the effective form factor of the proton are measured from the production threshold to 3.0 GeV/ using the invariant-mass spectrum. The ratio of electric and magnetic form factors of the proton is determined from the analysis of the proton-helicity angular distribution