Photovoltage Oscillations in Encapsulated Graphene

We theoretically analyze the rise of photovoltage oscillations in hexagonal boron-nitride (h-BN) encapsulated monolayer graphene (h-BN/graphene/h-BN) when irradiated with terahertz radiation. We use an extension of the radiation-driven electron orbit model, successfully applied to study the oscillations obtained in irradiated magnetotransport of GaAs/AlGaAs heterostructures. The extension takes mainly into account that now the carriers are massive Dirac fermions. Our simulations reveal that the photovoltage in these graphene systems presents important oscillations similar to the ones of irradiated magnetoresistance in semiconductor platforms but in the terahertz range. We also obtain that these oscillations are clearly affected by the voltages applied to the sandwiched graphene: a vertical gate voltage between the two hBN layers and an external positive voltage applied to one of the sample sides. The former steers the carrier effective mass and the latter the photovoltage intensity and the oscillations amplitude. The frequency dependence of the photo-oscillations is also investigated.

Relativistic Effects for a Hydrogen Rydberg Atom in a High-Frequency Laser Field: Analytical Results

Previously published analytical results for the effects of a high-frequency laser field on hydrogen Rydberg atoms demonstrated that the unperturbed elliptical orbit of the Rydberg electron, generally is engaged simultaneously in the precession of the orbital plane about the direction of the laser field and in the precession within the orbital plane. These results were obtained while disregarding relativistic effects. In the present paper, we analyze the relativistic effect for hydrogenic Rydberg atoms or ions in a high-frequency linearly- or circularly-polarized laser field, the effect being an additional precession of the electron orbit in its own plane. For the linearly-polarized laser field, the general case, where the electron orbit is not perpendicular to the direction of the laser field, we showed that the precession of the electron orbit within its plane can vanish at some critical polar angle θc of the orbital plane. We calculated analytically the dependence of the critical angle on the angular momentum of the electron and on the parameters of the laser field. Finally, for the particular situation, where the electron orbit is perpendicular to the direction of the laser field, we demonstrated that the relativistic precession and the precession due to the laser field occur in the opposite directions. As a result, the combined effect of these two kinds of the precession is smaller than the absolute value of each of them. We showed that by varying the ratio of the laser field strength F to the square of the laser field frequency ω, one can control the precession frequency of the electron orbit and even make the precession vanish, so that the elliptical orbit of the electron would become stationary. This is a counterintuitive result.

Relationship between Quantum Physics and Maxwell’s Equations in the Model of a Hydrogen Atom

An attempt to bring together two different theories – classical electrodynamics and quantum mechanics is made. On the example of a hydrogen atom the problem of the hypothetic electron fall into a nucleus by means of the energy conservation law is examined. The essence of the present approach consists in the assumption, that the energy and momentum of an electron in quantum model are proportional to corresponding electromagnetic fluxes. In order to achieve the result, the new formula of momentum flux density not using Poynting vector was proposed. It states that the momentum flux depends not only on electric and magnetic components of the field, but also on a frequency of an electromagnetic wave. As the main result, it was demonstrated that the total including annihilation energy of an electron in Bohr’s atom model is equal to energy of a free electron mc2 without any mention of Relativity. An electromagnetic field inside an atom occurs quantized for each electron orbit. An additional consequence shows that the two fundamental definitions of quantum energy mc2 and ħω are interrelated. If ħω is admitted according to quantum physics, then mc2 follows automatically and vice versaю

Strain-Tuned Nodal Ring in Two-Dimensional Zn3C6S6 Monolayers

The nodal ring material has recently attracted wide attention due to its singular properties and potential applications in spintronics. Here, two-dimensional Zn3C6S6 is calculated and discussed by using first-principle calculations. We found that two-dimensional Zn3C6S6 can generate a nodal ring at 10% compressive strain, and the existence of the ring is proved by a partial charge density map. And as the compressive strain increases, the nodal ring does not disappear. At the same time, the stability of the electron-orbit coupling to the nodal ring is applied. Our findings indicate that the two-dimensional Zn3C6S6 is promising in new electronic and spintronic applications.

Hydrogen production by photocatalysis method of glutamic acid and activated carbon

This research is purposed to produces hydrogen gas as an alternative fuels by environmentally friendly photo catalysis method. The photo catalyst was made of glutamic acid (C5H9NO4) and activated carbon both are dissolved in water in closed glass tube. In addition, halogen lamp with wavelength of 560 nm-580 nm was used as the lighting source. The heat from halogen lamp makes an electron orbit in the catalyst to be elliptical and polar. The photon from halogen lamp makes the electron leaps from its orbit. While the defective graphene on activated carbon gets energy from heat and photon, they will generate a magnetic field. This magnetic field energizes electron spin in glutamic acid and water while the active force in the defect of the carbon attracts the carbon atom in glutamic acid that makes it becomes more active. As a result hydrogen is produced from water. Hydrogen gas produced by the system was measured by MQ-8 sensor inside the reactor tube. The sensor was connected to microcontroller and recorded into computer memory with Arduino Uno Software. Photo catalysis process was tested for 20 minutes. The result shows that the highest hydrogen production occurs at glutamic acid solution with 225 ppm activated carbon.

A New Interpretation of Classical Electromagnetic Theory at the Micro Level

Because Maxwell's classical electromagnetic theory is a macroscopic electromagnetic theory, this paper attempts to establish a new theory of microscopic expression of macroscopic electromagnetic theory to compensate for the shortcomings of macroscopic electromagnetic theory at the micro level. Among them, under the microscopic electromagnetic theory system, the current will be further interpreted as the momentum flow produced by the directed collision between electrons; the charge will be further interpreted as a form of expression of electron motion; the voltage will be further interpreted as the potential difference (energy level difference) of the electron orbit. Finally, this paper successfully developed a new theory of microscopic expression of Maxwell's macroscopic electromagnetic theory by introducing microscopic atomic physics and rigid body mechanics models.

First measurements with the K-monochromator at the European XFEL

Hard X-ray free-electron lasers (XFELs) generate intense coherent X-ray beams by passing electrons through undulators, i.e. very long periodic magnet structures, which extend over hundreds of meters. The SASE1 and SASE2 undulator systems of the European XFEL consist of 35 segments with variable-gap planar undulators which are initially tuned to precise on-axis magnetic field strengths in a magnetic measurement laboratory to keep an important quality parameter – the K-value variation from segment to segment – below a certain limit (3 × 10−4 for 12 keV photon energy). After tunnel installation only photon-based methods can determine the K-values of undulator segments with a similar accuracy. The synchrotron radiation from a single or a few segments can be spectrally filtered by a dedicated crystal monochromator (K-monochromator) and recorded with a photodiode or with an imager that provides 2D information, tuned for high sensitivity to detect low photon densities from distant single undulator segments. This instrumentation is applied for electron orbit analysis and optimization, and adjustment of individual undulators in terms of their central magnetic axis with respect to the electron beam. Single undulator segments were analysed by scanning the monochromator crystal angle and detecting the steepest slope of a photodiode signal. Alternatively, in the imaging method, an imager recorded the radiation cone of electrons passing through the undulator segment. From the spatial distribution of the radiation, the K-parameter was determined with a sufficiently high relative accuracy.

Features of relativistic electron radiation in storage rings

The formulation of the problem is due to the fact that the spectral properties of radiation in alternating magnetic fields, as compared with homogeneous fields, differ little, but the angular characteristics depend significantly on betatron oscillations. Because the dynamics of an electron in the magnetic systems of accelerators is rather complicated, a number of simplifications has been made here. The asymptotic formulas for the spectral and angular distributions of the radiation intensity with the first quantum correction have been obtained by Schwinger’s operator method. For them, as well as for the angular characteristics of synchrotron light, approximate expressions are given, allowing researchers to determine the desired properties of photon emission at certain points of the electron orbit.

Quantitative Conditions and Convergent Operations That Are Compatible With the Universe as a Persistent Generator of Successive Simulations

         The capacity for computer-like simulations to be generated by massive information processing from electron-spin potentials supports Bostrom’s hypothesis that matter and human cognition might reflect simulations. Quantitative analyses of the basic assumptions indicate the universe may display properties of a simulation where photons behave as pixels and gravitons control the structural organization. The Lorentz solution for the square of the light and entanglement velocities converges with the duration of a single electron orbit that ultimately defines properties of matter. The approximately one trillion potential states within the same space with respect to the final epoch of the universe indicate that a different simulation, each with intrinsic properties, has been and will be generated as a type of tractrix defined by ±2 to 3 days (total duration 5 to 6 days). It may define the causal limits within a simulation. Because of the intrinsic role of photons as the pixel unit, phenomena within which flux densities are enhanced, such as human cognition (particularly dreaming) and the cerebral regions associated with those functions, create the conditions for entanglement or excess correlations between contiguous simulations. The consistent quantitative convergence of operations indicates potential validity for this approach. The emergent solutions offer alternative explanations for the limits of predictions for multivariate phenomena that could be coupled to more distal simulations.