Making An Observation Without Making An Observation: “Seeing” Knowledge Embedded In The Physical World With One’s Own Eyes

In electron shelving, one kind of quantum jump in which an electron in an atom moves in a discontinuous fashion to another energy level, a person can "see" knowledge that a weak transition (which is very slow) has occurred since it is proven that a strong transition (which is very fast) has not occurred in the time in which the strong transition can occur. This is a null measurement. There is no physical detection of the photon in the weak transition. There is only the logical deduction that the weak transition occurred since one cannot detect the photon in the strong transition, the only other possible transition. Looking at the interruption in the fluorescence that occurs in the strong transition, a “dark” interval, is "seeing" the knowledge resulting from the logical deduction. The significance of a null measurement in leading to the conclusion that one can "see" the knowledge resulting from a logical deduction is discussed. The null measurement in the weak transition is one form of Einstein’s spooky action where something not physical occurring in the possible strong transition leads to the occurrence of the weak transition. (2021 April Meeting of the American Physical Society, https://meetings.aps.org/Meeting/APR21/Session/KP01.48)

△S=1 Weak Transitions in Skyrme model Generalized up to Quartic Terms

<p>We investigate △S=1 weak transition in the light of most general Skyrme type lagrangian containing terms up to quartic terms in field gradients. The additional parameters in the lagrangian are taken from pion-pion scattering data. Our decay amplitudes for anticommutator term in the Skyrme lagrangian shows much improvement over the Skyrme values. S-wave decay amplitudes are also reasonably reproduced in the model.</p>

X-ray absorption linear dichroism at the Ti K-edge of rutile (001) TiO2 single crystal

X-ray absorption linear dichroism of rutile TiO2 at the Ti K-edge provides information about the electronic states involved in the pre-edge transitions. Here, linear dichroism with high energy resolution is analyzed in combination with ab initio finite difference method calculations and spherical tensor analysis. It provides an assignment of the three pre-edge peaks beyond the octahedral crystal field splitting approximation and estimates the spatial extension of the corresponding final states. It is then discussed for the first time the X-ray absorption (XAS) of pentacoordinated titanium atoms due to oxygen vacancies and it is found that, similarly to anatase TiO2, rutile is expected to exhibit a transition on the low-energy side of peak A3. Its apparent absence in the experiment is related to the degree of p–d orbital mixing which is small in rutile due to its centrosymmetric point group. A recent XAS linear dichroism study on anatase TiO2 single crystals has shown that peak A2 has an intrinsic origin and is due to a quadrupolar transition to the 3d energy levels. In rutile, due to its centrosymmetric point group, the corresponding peak A2 has a small dipole moment explaining the weak transition. The results are confronted with recent picosecond X-ray absorption spectroscopy on rutile TiO2 nanoparticles.

Structural and optical properties of Dy3+ doped Sr2SiO4 phosphors

Dysprosium doped strontium silicate phosphor namely (Sr2SiO4:Dy3+) was prepared by low-temperature solution combustion method using urea (CO(NH2)2) as a fuel. The material was characterized by powder X-ray diffraction (XRD), FT-IR, SEM and EDX. The average crystallite sizes was calculated by Scherer formula. Thermoluminescence study was carried out for the phosphor which showed single glow curve. The kinetic parameter were calculated by using Chen’s glow curve method. Photoluminescence spectra revealed strong transition at 473 nm (blue), 571 nm (yellow) and weak transition at 645 nm (red). These peaks were assigned to transition 4F9/2 →6H15/2, 13/2, 11/2. CIE graph of Sr2SiO4:Dy3+ phosphor is suitable for the generation of white light emission.