A thermodynamically consistent quasi-particle model without temperature-dependent infinity of the vacuum zero point energy

In this Letter, an improved quasi-particle model is presented. Unlike the previous approach of establishing quasi-particle model, we introduce a classical background field (it is allowed to depend on the temperature) to deal with the infinity of thermal vacuum energy which exists in previous quasi-particle models. After taking into account the effect of this classical background field, the partition function of quasi-particle system can be made well-defined. Based on this and following the standard ensemble theory, we construct a thermodynamically consistent quasi-particle model without the need of any reformulation of statistical mechanics or thermodynamical consistency relation. As an application of our model, we employ it to the case of (2+1)$(2+1)$ flavor QGP at zero chemical potential and finite temperature and obtain a good fit to the recent lattice simulation results of Borsányi et al. A comparison of the result of our model with early calculations using other models is also presented. It is shown that our method is general and can be generalized to the case where the effective mass depends not only on the temperature but also on the chemical potential.     

Mass without scalars

We attempt to show that fundamental scalar fields can be eliminated from the theory of weak and electromagnetic interactions. We do this by constructing an explicit example in which the scalar field sectors are replaced by strongly interacting gauge systems. Unlike previous examples, our present work gives a natural explanation for fermion masses. The cost is a significant expansion of the size of the gauge group.     

Circuit modeling of a vacuum gap during breakdown

In this paper several aspects of circuit modeling of a vacuum gap during breakdown are improved or introduced for the first time. More accurate perveance formulas are derived by the method of tracing electron trajectories in the self-consistent electric field calculated by the finite element method. The formula for maximum anode current density is also derived by the same method. A practical model of anode heating is proposed, by which transient anode temperature is calculated coupled with gap voltage and current, providing more accurate modeling of anode plasma initiation. The circuit model of a vacuum gap during breakdown incorporating all these features is implemented as a subcircuit element in the PSPICE     

Arc voltage of a fast triggered vacuum gap

At high current, the performance of triggered vacuum gaps (TVGs) is limited by constriction of the vacuum arc. Several concentrated modes can be defined, i.e., foot point, anode spot, and intense arc mode. In all cases, small, luminous, high-temperature spots (from melting to boiling temperature) appear on the anode surface. In accordance with the anodic mode, the arc voltage has different characteristics (quiet and low or with high-frequency noise). The arc voltage is measured for different electrode configurations for a conduction time of 27 μs and for peak current up to 45 kA. For small gap distances (1-1.5 mm), the arc voltage is quiet and low (20 to 30 V) and almost independent of the peak current. For greater distances, the arc voltage increases with the distance and the peak current. If the peak current is higher than the threshold interruption current, the arc voltage is high and noisy. These overvoltages, with a frequency of about one megahertz, can reach more than 1000 V. These overvoltages disappear completely after about 15 μs, and the voltage decreases     

真空短间隙微弧级联效应观测

利用0.5 mm间隙微通道板成像器观测了微弧放电的斑点级联效应.实验发现,微弧阴极斑点的运动轨迹呈多类型的折线轨迹,斑点间隙在200—300 μm,首发射阴极斑点的放电强度比次级斑点高一个量级以上,而且次级斑点之间的放电强度相对稳定,次级斑点在放电阴极表面无融蚀现象.实验表明,次级斑点产生机制与首发射存在较强的依赖关系. 关键词： 阴极斑点 微弧级联 微通道板成像器     

真空短间隙微弧级联效应观测

利用0.5 mm间隙微通道板成像器观测了微弧放电的斑点级联效应.实验发现,微弧阴极斑点的运动轨迹呈多类型的折线轨迹,斑点间隙在200—300 μm,首发射阴极斑点的放电强度比次级斑点高一个量级以上,而且次级斑点之间的放电强度相对稳定,次级斑点在放电阴极表面无融蚀现象.实验表明,次级斑点产生机制与首发射存在较强的依赖关系.     

Sculpting the vacuum in a photonic band gap micro-chip

We describe the engineering of the electromagnetic vacuum in a 2D–3D photonic bandgap (PBG) hetero-structure. This facilitates the development of novel active devices and the observation of novel quantum electrodynamic phenomena. We consider a specific architecture suitable as an all-optical micro-transistor capable of novel ultra-fast response with low switching power requirements. This relies on a unique collective atomic switching and population inversion achieved by coherent resonant pumping in a suitably engineered vacuum. Specific waveguide architectures within the 3D PBG micro-chip provide local density-of-states (LDOS) peaks near their cutoff frequency. These provide “building blocks” for electromagnetic vacuum engineering without recourse to conventional high Q-factor micro-cavities. For the all-optical micro-transistor, a fork shape LDOS within the micro-chip is desirable, using trimodal waveguide architecture. We delineate the functional robustness of these architectures to disorder caused by manufacturing errors within the PBG micro-chip.     

Electromagnetic tornado in the vacuum gap of a pulsar

The solution for an electromagnetic tornado that describes the motion in the discharge filament of breakdown in the vacuum gap of a pulsar has been obtained. This solution can serve as an explanation of the observed circular polarization of giant radiation pulses from pulsars.     

Dynamical dark energy with a constant vacuum energy density

We present a holographic dark-energy model in which the Newton constant GN$G_N$ scales in such a way as to render the vacuum energy density a true constant. Nevertheless, the model acts as a dynamical dark-energy model since the scaling of GN$G_N$ goes at the expense of deviation of concentration of dark-matter particles from its canonical form and/or of promotion of their mass to a time-dependent quantity, thereby making the effective equation of state (EOS) variable and different from −1 at the present epoch. Thus the model has a potential to naturally underpin Dirac's suggestion for explaining the large-number hypothesis, which demands a dynamical GN$G_N$ along with the creation of matter in the universe. We show that with the aid of observational bounds on the variation of the gravitational coupling, the effective-field theory IR cutoff can be strongly restricted, being always closer to the future event horizon than to the Hubble distance. As for the observational side, the effective EOS restricted by observation can be made arbitrary close to −1, and therefore the present model can be considered as a “minimal” dynamical dark-energy scenario. In addition, for nonzero but small curvature (|Ω_k0|?0.003)$(|{\Omega }_{k0}|?0.003)$, the model easily accommodates a transition across the phantom line for redshifts z?0.2$z?0.2$, as mildly favored by the data. A thermodynamic aspect of the scenario is also discussed.     

Excess electron energy in vacuum diodes

The mechanism for generation of electrons with the anomalous energy in the spectrum of powerful nanosecond electron beams is investigated. One-dimensional propagation of the beam between spherical electrodes in vacuum diodes with a large potential difference is considered. It is shown that the excess electron energy increases as the curvature radius of the cathode decreases and the beam current is conserved. Theoretical results are compared with the experimental data.     

Variable energy gap of SiCN nanopowders

SiCN and SiC nanopowders were prepared by infrared laser pyrolysis of gaseous precursors starting from a SiH₄C₂H₂NH₃ gas mixture. The SiCN powders were composed of an amorphous phase ascribed to the ternary compound with a β-SiC crystalline phase, while the SiC powders consisted of β phase only. The chemical bonding and the local atomic order in the SiCN powders are much more complicated than those of pure SiCSi₃N₄ mixtures and are strongly dependent on the variation in the initial gas composition. The average grain size was estimated from X-raydiffraction (XRD) patterns and atomic force microscopy (AFM). The UV-VIS transmittance data were used for the bandgap determination in these new materials. Absorption studies suggested that the direct energy gap is more favourable in SiCN and SiC nanoparticles and is blueshifted with regard to the crystalline bulk (SiC). The change of type of band-to-band transition in SiC nanopowders, due to the size effects, and increasing of the energy gap value in SiCN powders with different local atomic arrangement, makes them attractive for blue-UV optoelectronic applications. PACS 61.46.+w; 78.70.Ck; 68.3.Ps; 78.40.-q     

String localization and vacuum energy finiteness

The vacuum energy density of a general closed string model is calculated by considering the theory in a box and is found to diverge. The clear discrepancy with the finite value of the total vacuum energy is attributed to the inability to maintain conformal invariance while localizing the closed string.     

Electron excess energy in vacuum diodes

The study is devoted to the nature of anomalous electrons in the spectrum of intense electron beams. The case of one-dimensional beam propagation between spherical electrodes in vacuum diodes with a large potential difference is considered. The results are compared to available experimental data.     

Gravitational collapse with decaying vacuum energy

The effect of dark energy on the end state of spherical radiation collapse is considered within the context of the cosmic censorship hypothesis. It is found that it is possible to have both black holes as well as naked singularities.     

Influence of vacuum energy on scattering

We deal with photon-electron scattering which occurs between two uncharged conducting parallel plates moving away from each other at a constant velocity. The electromagnetic vacuum field between two plates is defined by the configuration of space and also interacts with the electrons. We show the relevant operators for both the electron and photon fields and the computation of the corresponding Feynman propagator,S-matrix, and scattering cross section, taking into account the influence of the changeable vacuum field. Correction terms in the computedS-matrix and scattering cross section manifest the influence of the changeable vacuum field. We analyze an example for low-energy scattering of the influence of the changeable vacuum field upon the scattering cross section.     

高压多脉冲真空间隙击穿实验研究

 在真空间隙击穿机理的理论基础上,设计了高压多脉冲下真空间隙的击穿实验方案,对相同材料的多对电极间隙在高压单脉冲和三脉冲下的真空击穿特性进行了实验研究。实验结果与脉冲下真空间隙的击穿机理相符,对脉冲数量增加对真空间隙宏观击穿场强的影响进行了验证,推断出了决定真空间隙宏观击穿场强的关键因素,并对多脉冲加速间隙最大宏观场强的设计提出了建议。