The Schwarzschild black hole in f(R) exist superradiation phenomenon

For the relationship of the limit $y$ of the incident particle under the superradiance of the preset boundary (${\mu} = {y}{\omega}$)and the limit $y$ of the incident particle under the Hawking radiation of the preset boundary (${y}{\mu} ={\omega}$),we find the relationship between black hole thermodynamics and superradiation, and use boundary conditions to establish the relationship between y and R. We find that the black hole energy and momentum tensor is transformed into an effective potential. When the effective potential has a potential barrier, then we know that the Schwarzschild black hole in f(R) exist superradiation phenomenon.

Intensity of Radiative Recombination in the Germanium/Silicon Nanosystem with Germanium Quantum Dots

It is shown that in a germanium/silicon nanosystem with germanium quantum dots, the hole leaving the germanium quantum dot causes the appearance of the hole energy level in the bandgap energy in a silicon matrix. The dependences of the energies of the ground state of a hole and an electron are obtained as well as spatially indirect excitons on the radius of the germanium quantum dot and on the depth of the potential well for holes in the germanium quantum dot. It is found that as a result of a direct electron transition in real space between the electron level that is located in the conduction band of the silicon matrix and the hole level located in the bandgap of the silicon matrix, the radiative recombination intensity in the germanium/silicon nanosystem with germanium quantum dots increases significantly.

Bounds on warm dark matter from Schwarzschild primordial black holes

We consider light dark matter candidates originated from the evaporation of Schwarzschild primordial black holes, with masses in the range $$10^{-5}$$ 10 - 5 –$$10^9$$ 10 9 g. These candidates are beyond standard model particles with negligible couplings to the other particles, so that they interact only gravitationally. Belonging to the category of warm dark matter, they nevertheless spoil structure formation, with a softer impact for increasing values of the candidate spin. Requiring such candidates to fully account for the observed dark matter, we find that the scenario of black hole domination is ruled out for all spin values up to 2. For the scenario of radiation domination, we derive upper limits on the parameter $$\beta $$ β (the primordial black hole energy density at formation over the radiation one), which are less stringent the higher the candidate spin is.

Formation of the Kaolin Structure Treated by Pressure

To form the technological properties of clays, various methods of their activation have been developed, the essence of which is that when processing clays, their structure (defectiveness) changes, which forms the energy potential of clay particles, and the latter is realized in the form of "specified" physicochemical properties of clays. In this regard, the effect of stress pressure on the change in the defectiveness of structural elements of kaolin was studied. Experimental studies showed that the pressure value P = 150 MPa was the boundary value at which different conditions for the formation of defectiveness of structural elements of kaolin were observed. High pressure has a multidirectional effect on the defectiveness formation of the kaolin structural elements: a package, a mineral, a colloid and an aggregate. In a package of kaolinite mineral, the defectiveness increases with increasing pressure. Defects are formed due to the removal of Al, Fe, Mg, Si ions from the octahedral and tetrahedral sheets. Al ions are the most sensitive to pressure. The removal of ions entails deformation of the packet and the formation of "hole" energy centers. Pressure up to 0–150 MPa has a greater effect on the formation of defectiveness (calculated correlation coefficient rс = 0.86) than in the range 150–800 MPa (rс = 0.82). In the kaolinite mineral at pressures up to 150 MPa, a decrease in defectiveness is observed due to the ordering of the structure under pressure (rс = 0.67). At pressures above 150 MPa, an increase in the defectiveness of the kaolinite mineral (rс = –0.72) is observed due to the destruction of hydrogen bonds between the packets, which entails the sliding and rotation of the structural packets among themselves. In a colloid (particle), with an increase in pressure to 150 MPa, the structural defect decreases due to an increase in the colloid density (rс = 0.67). In the pressure range of 150–800 MPa, it is rather difficult to reveal the effect of pressure on the formation of defectiveness (rс = 0.37). In the aggregate, with an increase in pressure to 150 MPa, the defectiveness of the structure increases due to crushing of particles, sliding and displacement of particles among themselves (rс = 0.95). In the pressure range of 150–800 MPa, it is rather difficult to reveal the influence of pressure on the formation of defectiveness (rс = 0.58), although the tendency increases with increasing pressure, the defectiveness of the aggregate remains.

The Quantum Mechanism of AGNs’ Jets

Active galactic nuclei (AGNs) are throwing in the interstellar space huge jets of energy in the form of elementary particles. The calculation of the energy density of space in the centre of the black hole with the mass of the Sun shows that in the space-time singularity of such a black hole energy density of space there is so low that atoms become unstable and fall apart into elementary particles. In this sense, AGN is a rejuvenating system of the universe. It transforms its own old matter into fresh energy in the form of jets.

Space-time singularities, Schwarzschild energy density, and AGN’s jets

Active galactic nuclei (AGNs) are throwing in the interstellar space huge jets of energy in the form of elementary particles. The calculation of the energy density of space in the centre of the black hole with the mass of the Sun shows that in the space-time singularity of such a black hole energy density of space there is so low that atoms become unstable and fall apart into elementary particles. In this sense, AGN is a rejuvenating system of the universe. It transforms its own old matter into fresh energy in the form of jets.

Formation of the Kaolin Structure Treated by Pressure

To form the technological properties of clays, various methods of their activation have been developed, the essence of which is that when processing clays, their structure (defectiveness) changes, which forms the energy potential of clay particles, and the latter is realized in the form of "specified" physicochemical properties of clays. In this regard, the effect of stress pressure on the change in the defectiveness of structural elements of kaolin was studied. Experimental studies showed that the pressure value P = 150 MPa was the boundary value at which different conditions for the formation of defectiveness of structural elements of kaolin were observed. High pressure has a multidirectional effect on the defectiveness formation of the kaolin structural elements: a package, a mineral, a colloid and an aggregate. In a package of kaolinite mineral, the defectiveness increases with increasing pressure. Defects are formed due to the removal of Al, Fe, Mg, Si ions from the octahedral and tetrahedral sheets. Al ions are the most sensitive to pressure. The removal of ions entails deformation of the packet and the formation of "hole" energy centers. Pressure up to 0–150 MPa has a greater effect on the formation of defectiveness (calculated correlation coefficient rс = 0.86) than in the range 150–800 MPa (rс = 0.82). In the kaolinite mineral at pressures up to 150 MPa, a decrease in defectiveness is observed due to the ordering of the structure under pressure (rс = 0.67). At pressures above 150 MPa, an increase in the defectiveness of the kaolinite mineral (rс = –0.72) is observed due to the destruction of hydrogen bonds between the packets, which entails the sliding and rotation of the structural packets among themselves. In a colloid (particle), with an increase in pressure to 150 MPa, the structural defect decreases due to an increase in the colloid density (rс = 0.67). In the pressure range of 150–800 MPa, it is rather difficult to reveal the effect of pressure on the formation of defectiveness (rс = 0.37). In the aggregate, with an increase in pressure to 150 MPa, the defectiveness of the structure increases due to crushing of particles, sliding and displacement of particles among themselves (rс = 0.95). In the pressure range of 150–800 MPa, it is rather difficult to reveal the influence of pressure on the formation of defectiveness (rс = 0.58), although the tendency increases with increasing pressure, the defectiveness of the aggregate remains.

Crystallographic Orientation Effect On Hole Polar Optical Phonon Scattering Rates in Thin Gaas/Alxga1-Xas Quantum Wells

We report on hole polar optical phonon scattering processes in thin GaAs/AlxGa1-xAs quantum wells grown in various crystallographic directions, such as [001], [110]. Using the dielectric continuum model we focus on how the different scattering processes of holes with interface phonon modes depend on the initial hole energy. In our work, we use the Luttinger-Kohn (LK) 6×6 k.p Hamiltonian with the envelope function approximation, from which we compute numerically the electronic structure of holes for a thin quantum well sustaining only one bound state for each type of hole. Due to mixing between the heavy, light, and split off bands, hole subbands exhibit strong nonparabolicity and important warping that have their word to say on physical properties. Detailed and extensive calculations that the rates for intra-subband scattering processes differ significantly from those of bulk GaAs because of quantization and reduced dimensionality. Moreover, the study of scattering as a function of hole energy shows that the trend of the scattering rates is governed mostly by i) overlap integrals and ii) the density of the final states to which the hole scatters. The influence of warping, in the hole energy dispersion, on the phonon scattering rates is also explored and found to be important when the initial hole energy is high. Our calculations show evidence of strong anisotropy in the scattering rates especially for processes involving the heavy hole subband, which anisotropy is in fact quite important and far from being negligible. However, strain effect can reduce scattering rates.

Hole States in Spherical Quantum Nanoheterosystem with Intermediate Spin-Orbital Interaction

The hole energy spectrum has been studied for the spherical semiconductor nanoheterosystem with the cubic symmetry. The exact solutions of the Schrödinger equation for the ground and excited hole states are presented within the framework of the 6-band Luttinger Hamiltonian and the finite gap of bands with the corresponding boundary conditions. Dependence of the holes energies from the radius of the quantum dot has been calculated for the GaAs/AlAs heterostructure. Obtained results where compared with data obtained using the infinite potential well model, as well as the single-band model for heavy and light holes.