Zeta functions and the Casimir energy

We use zeta function techniques to give a finite definition for the Casimir energy of an arbitrary ultrastatic spacetime with or without boundaries. We find that the Casimir energy is intimately related to, but not identical to, the one-loop effective energy. We show that in general the Casimir energy depends on a normalization scale. This phenomenon has relevance to applications of the Casimir energy in bag models of QCD.Within the framework of Kaluza-Klein theories we discuss the one-loop corrections to the induced cosmological and Newton constants in terms of a Casimir like effect. We can calculate the dependence of these constants on the radius of the compact dimensions, without having to resort to detailed calculations.     

The negative energy density for a three-single-electron state in the Dirac field

We examine the energy density produced by a state vector which is the superposition of three single electron states in the Dirac field in the four-dimensional Minkowski spacetime. We derive the conditions on which the energy density can be negative. We then show that the energy density satisfies two quantum inequalities in the ultrarelativistic limit.     

Thermodynamics of diffusive DM/DE systems

We discuss the energy density, temperature and entropy of dark matter (DM) and dark energy (DE) as functions of the scale factor a in an expanding universe. In a model of non-interacting dark components we repeat a derivation from thermodynamics of the well-known relations between the energy density, entropy and temperature. In particular, the entropy is constant as a consequence of the energy conservation. We consider a model of a DM/DE interaction where the DM energy density increase is proportional to the particle density. In such a model the dependence of the energy density and the temperature on the scale factor a is substantially modified. We discuss (as a realization of the model) DM which consists of relativistic particles diffusing in an environment of DE. The energy gained by the dark matter comes from a cosmological fluid with a negative pressure. We define the entropy and free energy of such a non-equilibrium system. We show that during the universe evolution the entropy of DM is increasing whereas the entropy of DE is decreasing. The total entropy can increase (in spite of the energy conservation) as the DM and DE temperatures are different. We discuss non-equilibrium thermodynamics on the basis of the notion of the relative entropy.     

Energy Spectrum of Two-Component Bose-Einstein Condensates in Optical Lattices

With the method of Green's function, we investigate the energy spectra of two-component ultracold bosonic atoms in optical lattices. We find that there are two energy bands for each component. The critical condition of the superfluid-Mott insulator phase transition is determined by the energy band structure. We also find that the nearest neighboring and on-site interactions fail to change the structure of energy bands, but shift the energy bands only. According to the conditions of the phase transitions, three stable superfluid and Mott insulating phases can be found by adjusting the experiment parameters. We also discuss the possibility of observing these new phases and their transitions in further experiments.     

Mesic molecules and muon catalysed fusion

We discuss the energy spectrum of mesic molecules, reviewing the recent advances in the methods of calculations and in the measurements of the energy levels.We also present recent ideas concerning the possibility of using the muon catalysed fusion for energy production.     

Gravitational collapse of dark energy field configurations and supermassive black hole formation

Dark energy is the dominant component of the total energy density of our Universe. The primary interaction of dark energy with the rest of the Universe is gravitational. It is therefore important to understand the gravitational dynamics of dark energy. Since dark energy is a low-energy phenomenon from the perspective of particle physics and field theory, a fundamental approach based on fields in curved space should be sufficient to understand the current dynamics of dark energy. Here, we take a field theory approach to dark energy. We discuss the evolution equations for a generic dark energy field in curved space-time and then discuss the gravitational collapse for dark energy field configurations. We describe the 3 + 1 BSSN formalism to study the gravitational collapse of fields for any general potential for the fields and apply this formalism to models of dark energy motivated by particle physics considerations. We solve the resulting equations for the time evolution of field configurations and the dynamics of space-time. Our results show that gravitational collapse of dark energy field configurations occurs and must be considered in any complete picture of our Universe. We also demonstrate the black hole formation as a result of the gravitational collapse of the dark energy field configurations. The black holes produced by the collapse of dark energy fields are in the supermassive black hole category with the masses of these black holes being comparable to the masses of black holes at the centers of galaxies.     

Energy transfer rate in double-layer graphene systems: Linear regime

We theoretically investigate the energy transfer phenomenon in a double-layer graphene (DLG) system. We use the balance equation approach in linear regime and random phase approximation screening function to obtain energy transfer rates at different electron temperatures, densities and interlayer spacings. We find that the rate of energy transfer in the DLG is qualitatively similar to that obtained in the double-layer two-dimensional electron gas but its values are an order of magnitude greater. Also, at large electron temperature differences between two graphene layers, the electron density dependence of energy transfer is significantly different, particularly in case of unequal electron densities.     

Couplings between holographic dark energy and dark matter

We consider the interaction between dark matter and dark energy in the framework of holographic dark energy, and propose a natural and physically plausible form of interaction, in which the interacting term is proportional to the product of the powers of the dark matter and dark energy densities. We investigate the cosmic evolution in such models. The impact of the coupling on the dark matter and dark energy components may be asymmetric. While the dark energy decouples from the dark matter at late time, just as other components of the cosmic fluid become decoupled as the universe expands, interestingly, the dark matter may actually become coupled to the dark energy at late time. We shall call such a phenomenon incoupling. We use the latest type Ia supernovae data from the SCP team, baryon acoustics oscillation data from SDSS and 2dF surveys, and the position of the first peak of the CMB angular power spectrum to constrain the model. We find that the interaction term which is proportional to the first power product of the dark energy and dark matter densities gives an excellent fit to the current data.     

Energy Mechanism of Charges Analyzed in Real Current Environment

We analyze in this work the energy transfer process of accelerated charges, the mass fluctuations accompanying this process, and their inertial properties. Based on a previous work, we use here the dipole antenna, which is a very convenient framework for such analysis, for analyzing those characteristics. We show that the radiation process can be viewed by two energy transfer processes: one from the energy source to the charges and the second from the charges into the surrounding space. Those processes, not being in phase, result in mass fluctuations. The same principle is true during absorption. We show that in a transient period between absorption and radiation the dipole antenna gains mass according to the amount of absorbed energy and loses this mass as radiated energy. We rigorously prove that the gain of mass, resulting from electrical interaction has inertial properties in the sense of Newton's third low. We arrive to this result by modeling the reacting spacetime region by an electric dipole.     

Dynamics of individuals and swarms with shot noise induced by stochastic food supply

We study the Brownian dynamics of individual particles with energy depot in two dimensions and extend the model to swarms of such particles. We assume that the elements (energy depots) are provided at discrete times with packets of chemical energy which is subsequently converted into acceleration of motion. In contrast to the mechanical white noise which is incorporated in the equations of mechanical motion and has no preferred direction, the energetic noise, as discussed in this study, is directed and it does not reverse the direction of mechanical motion. We characterize the effective noise acting on the particles and show that the stochastic energy supply may be modeled as a shot-noise driven Ornstein-Uhlenbeck process in energy which finally results in fluctuations of the velocity. We study the energy and velocity distributions for different regimes and estimate the crossover time from ballistic to diffusion motion. Further we investigate the dynamics of swarms and find a transition from translational to rotational motion depending on the rate of the shot noise.     

Nonlinear triad interactions and the mechanism of spreading in drift-wave turbulence

We present the results of a derivation of the fluctuation energy transport matrix for the two-field Hasegawa-Wakatani model of drift wave turbulence. The energy transport matrix is derived from a two-scale direct interaction approximation assuming weak turbulence. We examine different classes of triad interactions and show that radially extended eddies, as occurs in penetrative convection, are the most effective in turbulence spreading. We show that in the near-adiabatic limit internal energy spreads faster than the kinetic energy. Previous theories of spreading results are discussed in the context of weak turbulence theory.     

Surface free energy of platinum nanoparticles at zero pressure: A molecular dynamic study

Metallic nanoparticles are interesting because of their use in catalysis and sensors. The surface energy of the FCC platinum nanoparticles are investigated via molecular dynamics simulation using Quantum Sutton–Chen (QSC) potential. We have calculated the Gibbs free energy for the FCC platinum bulk and also for its nanoparticle. All calculations have been carried out at zero pressure. We have used the thermodynamic integration method to obtain the Gibbs free energy. The total Gibbs free energy is taken as the sum of its central bulk and its surface free energy. We have calculated the free energy of a platinum nanoparticle as a function of temperature.     

Holographic Dark Energy in Higher Derivative Gravity with Varying Gravitational Constant

In this paper we investigate the holographic dark energy scenario in higher derivative gravity with a varying gravitational constant. We introduce a kind of energy density from higher derivative gravity which has role of the same as holographic dark energy. We obtain the exact differential equation , which determine the evolution of the dark energy density based on varying gravitational constant G. We also find out a cosmological application of our work by evaluating a relation for the equation of state of dark energy for low redshifts containing varying G correction.     

Stability of the curvature perturbation in dark sectors' mutual interacting models

We consider perturbations in a cosmological model with a small coupling between dark energy and dark matter. We prove that the stability of the curvature perturbation depends on the type of coupling between dark sectors. When the dark energy is of quintessence type, if the coupling is proportional to the dark matter energy density, it will drive the instability in the curvature perturbations; however if the coupling is proportional to the energy density of dark energy, there is room for the stability in the curvature perturbations. When the dark energy is of phantom type, the perturbations are always stable, no matter whether the coupling is proportional to the one or the other energy density.     

Vacuum local and global electromagnetic self-energies for a point-like and an extended field source

We consider the electric and magnetic energy densities (or equivalently field fluctuations) in the space around a point-like field source in its ground state, after having subtracted the spatially uniform zero-point energy terms, and discuss the problem of their singular behavior at the source’s position. We show that the assumption of a point-like source leads, for a simple Hamiltonian model of the interaction of the source with the electromagnetic radiation field, to a divergence of the renormalized electric and magnetic energy density at the position of the source. We analyze in detail the mathematical structure of such a singularity in terms of a delta function and its derivatives. We also show that an appropriate consideration of these singular terms solves an apparent inconsistency between the total field energy and the space integral of its density. Thus the finite field energy stored in these singular terms gives an important contribution to the self-energy of the source. We then consider the case of an extended source, smeared out over a finite volume and described by an appropriate form factor. We show that in this case all divergences in local quantities such as the electric and the magnetic energy density, as well as any inconsistency between global and space-integrated local self-energies, disappear.     

Autoionization of Ne projectiles in collisions with surfaces

We have measured the energy distributions of Ne autoionization electrons produced in collisions of 0.5–3 keV Ne⁺ ions with Al surfaces. We have found a strong broadening and a weak energy shift of the lines with increasing projectile energy. We have also identified the autoionization transitions leading to these lines.     

Light absorption and excitation energy transfer calculations in primitive photosynthetic bacteria

In photosynthetic organisms, light energy is converted into chemical energy through the light absorption and excitation energy transfer (EET) processes. These processes start in light-harvesting complexes, which contain special photosynthetic pigments. The exploration of unique mechanisms in light-harvesting complexes is directly related to studies, such as artificial photosynthesis or biosignatures in astrobiology. We examined, through ab initio calculations, the light absorption and EET processes using cluster models of light-harvesting complexes in purple bacteria (LH2). We evaluated absorption spectra and energy transfer rates using the LH2 monomer and dimer models to reproduce experimental results. After the calibration tests, a LH2 aggregation model, composed of 7 or 19 LH2s aligned in triangle lattice, was examined. We found that the light absorption is red shifted and the energy transfer becomes faster as the system size increases. We also found that EET is accelerated by exchanging the central pigments to lower energy excited pigments. As an astrobiological application, we calculated light absorptions efficiencies of the LH2 in different photoenvironments.     

高能宇宙射线数值模拟中能谱指数的标定

在利用TeV能区宇宙射线数值模拟数据研究朝前区强子相互作用时, 需要足够多的低空簇射事例样本。提出了可以通过降低FIXCHI（宇宙射线第一次相互作用高度）来提高高能宇宙射线数值模拟效率,但对相应的能谱指数进行标定是必要的。以1 TeV处直达概率为标准, 得到各能区的能谱强度, 并采用将能谱强度与能量进行线性拟合, 以标定能谱指数的方法, 使宇宙射线数值模拟的效率及准确率都大大提高。 In the study of hadronic interaction in the forward region by the simulation of cosmic ray, it is necessary to simulate large numbers of cosmic ray events with low first interaction height. We confirmed that by reducing the FIXCHI the efficiency of cosmic ray simulation can be improved. But the calibration for energy slope is needed. We got the energy slope based on the probability of direct arrived events with energy of 1 TeV, and fitted the intensity of spectrum with energy to make certain the energy slope of high energy cosmic ray. By this way, the efficiency and precision of cosmic ray simulation is greatly improved.     

Interacting New Agegraphic Viscous Dark Energy with Varying <Emphasis Type="Italic">G</Emphasis>

We consider the new agegraphic model of dark energy with a varying gravitational constant, G, in a non-flat universe. We obtain the equation of state and the deceleration parameters for both interacting and noninteracting new agegraphic dark energy. We also present the equation of motion determining the evolution behavior of the dark energy density with a time variable gravitational constant. Finally, we generalize our study to the case of viscous new agegraphic dark energy in the presence of an interaction term between both dark components.     

电子束横向泵浦柱形KrF系统时电子能量沉积的数值计算与物理分析

本文对电子束横向泵浦柱形Ar、Kr、F₂混合物时电子能量沉积用SANDYL程序作了数值计算,得到了能量沉积效率与混合物总压力,电子能量和混合物成份比的关系。另外,我们还用阻止本领公式对电子、质子能量沉积效率作了粗估,并为了质子束泵浦的准分子激光的理论模拟而进行了电子、质子能量损失的比较。