On Neutralization of Charged Black Holes

For non-spinning, charged (Reissner–Nordström) black holes, the particles with an opposite sign of charge with respect to that of the black hole will be pulled into the black hole by the extra electromagnetic force. Such a hole will be quickly neutralized so that there should not exist significantly charged, non-spinning black holes in the universe. The case of spinning, charged (Kerr–Newmann, KN) black holes is more complicated. For a given initial position and initial velocity of the particle, an oppositely charged particle does not always more easily fall into the black hole than a neutral particle. The possible existence of a magnetosphere further complicate the picture. One therefore cannot straightforwardly conclude that a charged spinning black hole will be neutralized. In this paper, we make the first step to investigate the neutralization of KN black holes without introducing a magnetosphere. We track the particle trajectories under the influence of the curved space–time and the electromagnetic field carried by the spinning, charged black hole. A statistical method is used to investigate the neutralization problem. We find a universal dependence of the falling probability into the black hole on the charge of the test particle, with the oppositely charged particles having a higher probability of falling. We therefore conclude that charged, spinning black holes without a magnetosphere should be quickly neutralized, consistent with people’s intuition. The neutralization problem of KN black holes with a corotating force-free magnetosphere is subject to further studies

Particle-number conserving analysis for the 2-quasiparticle and high-KK multi-quasiparticle states in doubly-odd 174,176{}^{174, 176}Lu

Two-quasiparticle bands and low-lying excited high-$K$ four-, six-, and eight-quasiparticle bands in the doubly-odd ${}^{174, 176}$Lu are analyzed by using the cranked shell model (CSM) with the pairing correlations treated by a particle-number conserving (PNC) method, in which the blocking effects are taken into account exactly. The proton and neutron Nilsson level schemes for ${}^{174, 176}$Lu are taken from the adjacent odd-$A$ Lu and Hf isotopes, which are adopted to reproduce the experimental bandhead energies of the one-quasiproton and one-quasineutron bands of these odd-$A$ Lu and Hf nuclei, respectively. Once the quasiparticle configurations are determined, the experimental bandhead energies and the moments of inertia of these two- and multi-quasiparticle bands are well reproduced by PNC-CSM calculations. The Coriolis mixing of the low-$K$ ($K=|\Omega_1-\Omega_2|$) two-quasiparticle band of the Gallagher-Moszkowski doublet with one nucleon in the $\Omega = 1/2$ orbital is analyzed.Comment: 8 pages, 5 figures, 2 tables, to be published at Chinese Physics

Path diversity improves the identification of influential spreaders

Identifying influential spreaders in complex networks is a crucial problem which relates to wide applications. Many methods based on the global information such as $k$-shell and PageRank have been applied to rank spreaders. However, most of related previous works overwhelmingly focus on the number of paths for propagation, while whether the paths are diverse enough is usually overlooked. Generally, the spreading ability of a node might not be strong if its propagation depends on one or two paths while the other paths are dead ends. In this Letter, we introduced the concept of path diversity and find that it can largely improve the ranking accuracy. We further propose a local method combining the information of path number and path diversity to identify influential nodes in complex networks. This method is shown to outperform many well-known methods in both undirected and directed networks. Moreover, the efficiency of our method makes it possible to be applied to very large systems.Comment: 6 pages, 6 figure

Cultural Values in Chinese Children's Animation: A Content Analysis of The Legend of Nezha

Permissions were not obtained for sharing the full text of this article.This study examined the dominant cultural value themes in The Legend of Nezha, a 52-episode Chinese award winning television animation series for children. Two contextual factors, the image and sex of the characters who endorsed the value themes in the scenes (N = 963), were also examined. Content analysis results showed that the traditional values (e.g., Hierarchy, Friendship, Wisdom, Perseverance, Collectivism, Humanitarianism, Family, and Nature) were more prevalent than the nontraditional themes (e.g., Self-interest, Pleasure, Equality, Beauty/youth, and Romanticism). In addition, the traditional values (except hierarchy) were more frequently associated with positive characters than with negative ones; the nontraditional value themes (except equality) were more frequently associated with negative characters than with positive ones. Furthermore, some values such as hierarchy, perseverance, harmony/collectivism and equality were more endorsed by male characters than by female characters; some values such as family, beauty/youth, and self-interest were endorsed more by female characters than by male characters. Altogether, these findings have indicated that some fundamental traditional Chinese values still dominate the mainstream culture albeit certain nontraditional values (e.g., self-interest, pleasure, and romanticism) are gaining their prominence in an age of modernization and globalization

Detectable MeV neutrinos from black hole neutrino-dominated accretion flows

Neutrino-dominated accretion flows (NDAFs) around rotating stellar-mass black holes (BHs) have been theorized as the central engine of relativistic jets launched in massive star core collapse events or compact star mergers. In this work, we calculate the electron neutrino/anti-neutrino spectra of NDAFs by fully taking into account the general relativistic effects, and investigate the effects of viewing angle, BH spin, and mass accretion rate on the results. We show that even though a typical NDAF has a neutrino luminosity lower than that of a typical supernova (SN), it can reach $10^{50}-10^{51}~{\rm erg~s^{-1}}$ peaking at $\sim 10$ MeV, making them potentially detectable with the upcoming sensitive MeV neutrino detectors if they are close enough to Earth. Based on the observed GRB event rate in the local universe and requiring that at least 3 neutrinos are detected to claim a detection, we estimate a detection rate up to $\sim$ (0.10-0.25) per century for GRB-related NDAFs by the Hyper-Kamiokande (Hyper-K) detector if one neglects neutrino oscillation. If one assumes that all Type Ib/c SNe have an engine-driven NDAF, the Hyper-K detection rate would be $\sim$ (1-3) per century. By considering neutrino oscillations, the detection rate may decrease by a factor of 2-3. Detecting one such event would establish the observational evidence of NDAFs in the universe.Comment: 7 pages, 2 figures, 2 tables, accepted for publication in PR