Atypical dependence of excited exciton energy levels and electron-hole correlation on emission energy in pyramidal InP-based quantum dots

We calculate the spectrum of excited exciton states in application-relevant self-assembled pyramidal quantum dots grown in InAs/InP and InAs/AlGaInAs material systems. These types of dots have been recently shown to combine the emission in the third optical fiber window with low surface density and a reasonable level of in-plane symmetry of emitters, which predestines them for studies on single- and entangled-photon emission and for corresponding applications. The spectrum of optically active excited states is crucial for successful resonant and quasi-resonant excitation of emitters, allowing for conservation of angular momentum and addressing individual selected quantum states. Here, we show that in both types of studied dots, due to their specific morphology of truncated pyramid, the density of excited-state ladder, especially the s–p shell splitting may follow an unconventional dependence on emission energy, opposite to the one typically met in regular quantum dots. We obtain this result via modeling based on available morphological data and calculation within the multi-band $${{\varvec{k}} {\cdot } {\varvec{p}}}$$ k · p envelope-function theory combined with the configuration-interaction method used to calculate exciton states. Then, we explain this observation in purely geometric terms, as a result of an increasing effective quantum confinement width in a pyramid that is progressively cut from the top. Additionally, we show that the inverted trend is also manifested in the amount of electron-hole correlation in the exciton ground state, which also shows an anomalous dependence on emission energy and quantum dot volume.

Statistical Analyses of the Energies of X-Ray Plateaus and Flares in Gamma-Ray Bursts

Distinct X-ray plateau and flare phases have been observed in the afterglows of gamma-ray bursts (GRBs), and most of them should be related to central engine activities. In this paper, we collect 174 GRBs with X-ray plateau phases and 106 GRBs with X-ray flares. There are 51 GRBs that overlap in the two selected samples. We analyze the distributions of the proportions of the plateau energy E plateau and the flare energy E flare relative to the isotropic prompt emission energy E γ,iso. The results indicate that they well meet the Gaussian distributions and the medians of the logarithmic ratios are ∼−0.96 and −1.39 in the two cases. Moreover, strong positive correlations between E plateau (or E flare ) and E γ,iso with slopes of ∼0.95 (or ∼0.80) are presented. For the overlapping sample, the slope is ∼0.80. We argue that most of X-ray plateaus and flares might have the same physical origin but appear with different features because of the different circumstances and radiation mechanisms. We also test the applicabilities of two models, i.e., black holes surrounded by fractured hyperaccretion disks and millisecond magnetars, on the origins of X-ray plateaus and flares.

Taxation of Assets Used to Generate Energy—In the Context of the Transformation of the Polish Energy Sector from Coal Energy to Low-Emission Energy

(1) Background—The aim of this paper was to indicate whether the taxation of facilities related to renewable or low-emission energy differed significantly from that of facilities generating electricity from coal. (2) Methods—The research was conducted using a descriptive method, and because of the legal nature of the article, a crucial role was played by the dogmatic method. (3) Results—The thesis according to which only the “construction part” is subject to the property tax is the result of many years of disputes between the taxpayers and the tax authorities. In practice, it is difficult to compare the tax burden on assets related to coal and low-emission power generation because of the construction of the tax base in Polish property tax law. Most often, however, the tax burden on assets, which is calculated in the context of the amount of energy produced, tends to favour coal-fired power generation. (4) Conclusion: The property tax regulations in Poland treat the assets used for energy production by all methods identically. In practice, because of the specificity of the tax base, this means a more favourable treatment of facilities associated with coal-fired power generation.

Environmental Cost Accounting

With the strengthen of people’s ability to use and transform nature, on the one hand, people acquire more resources from nature and make life more comfortable, on the other hand, the amount of waste that people emit has also increased rapidly. Excessive excavation of resources and disposal of waste emissions led to the deterioration of the environment, affecting the country's sustainable development and the Earth's ecological balance. In this paper, from the perspective of low-carbon economy, to explore corporate environmental cost recognition, measurement, collection, distribution methods, expectations for the relevant enterprises, especially high-polluting, high-emission energy-based enterprises to learn from.