Anomaly analysis of Hawking radiation from Kaluza-Klein black hole with squashed horizon

Considering gravitational and gauge anomalies at the horizon, a new method that to derive Hawking radiations from black holes has been developed by Wilczek et al. In this paper, we apply this method to non-rotating and rotating Kaluza-Klein black holes with squashed horizon, respectively. For the rotating case, we found that, after the dimensional reduction, an effective U(1) gauge field is generated by an angular isometry. The results show that the gauge current and energy-momentum tensor fluxes are exactly equivalent to Hawking radiation from the event horizon.Comment: 15 pages, no figures, the improved version, accepted by Eur. Phys. J.

Remarks on Hawking radiation as tunneling from the BTZ black holes

Hawking radiation viewed as a semiclassical tunneling process from the event horizon of the (2 + 1)-dimensional rotating BTZ black hole is carefully reexamined by taking into account not only the energy conservation but also the conservation of angular momentum when the effect of the emitted particle's self-gravitation is incorporated. In contrast to previous analysis of this issue in the literature, our result obtained here fits well to the Kraus-Parikh-Wilczek's universal conclusion without any modification to the Bekenstein-Hawking area-entropy formulae of the BTZ black hole.Comment: 12pages, no figure, use JHEP3.cls. Version better than published one in JHE

Experimental Realization of Parrondo's Paradox in 1D Quantum Walks

The Parrondo effect is a well-known apparent paradox where a combination of biased random walks displays a counterintuitive reversal in direction. These random walks can be expressed in terms of classical coin tossing games, leading to the surprising result that a combination of losing games can result in a winning game. There is now a large body of literature on quantum walks theoretically analyzing the quantum version of this effect, but to date, there have been no experimental observations of quantum Parrondo walks. Here, the first experimental verification of a quantum Parrondo walk within a quantum optics scenario is demonstrated. Based on the compact large-scale experimental quantum-walk platform, two rotation operators are implemented to realize the quantum Parrondo effect. The effect of quantum coherence in a quantum Parrondo walk is also investigated based on a delayed-choice scheme that cannot be realized with classical light. It is demonstrated that the Parrondo effect vanishes when the quantum walk has a completely decoherent initial state in a delayed-choice setting. Quantum walks are fundamental to multiple quantum algorithms, and this research provides motivation to expand the results to further explore quantum Parrondo walks.Munsif Jan, Qin-Qin Wang, Xiao-Ye Xu, Wei-Wei Pan, Zhe Chen, Yong-Jian Han, Chuan-Feng Li, Guang-Can Guo, and Derek Abbot

Experimental Realization of Parrondo's Paradox in 1D Quantum Walks

The Parrondo effect is a well-known apparent paradox where a combination of biased random walks displays a counterintuitive reversal in direction. These random walks can be expressed in terms of classical coin tossing games, leading to the surprising result that a combination of losing games can result in a winning game. There is now a large body of literature on quantum walks theoretically analyzing the quantum version of this effect, but to date, there have been no experimental observations of quantum Parrondo walks. Here, the first experimental verification of a quantum Parrondo walk within a quantum optics scenario is demonstrated. Based on the compact large-scale experimental quantum-walk platform, two rotation operators are implemented to realize the quantum Parrondo effect. The effect of quantum coherence in a quantum Parrondo walk is also investigated based on a delayed-choice scheme that cannot be realized with classical light. It is demonstrated that the Parrondo effect vanishes when the quantum walk has a completely decoherent initial state in a delayed-choice setting. Quantum walks are fundamental to multiple quantum algorithms, and this research provides motivation to expand the results to further explore quantum Parrondo walks.Munsif Jan, Qin-Qin Wang, Xiao-Ye Xu, Wei-Wei Pan, Zhe Chen, Yong-Jian Han, Chuan-Feng Li, Guang-Can Guo, and Derek Abbot

Study on the protective performance of high-performance multi-scale (SiCh-p+B4Cp)/5083Al ceramic array armor with excellent ballistic properties

Ceramic array armor suffers from insufficient constrained capability of ceramic units in the embedded armor structure, leading to weak interfacial bonding at ceramic unit connections, significantly reducing the overall ballistic performance. In this study, centimeter-sized SiC hexagonal prisms and micrometer-sized B4C powders were used as reinforcing materials. A high-strength, high-toughness, and multiscale array (SiCh-p + B4Cp)/5083Al armor with strong interfacial bonding was prepared using pressure infiltration technique. The (SiCh-p + B4Cp)/5083Al armor was combined with ultra-high molecular weight polyethylene and 6252 armor steel to form an integrated armor system. To investigate the effect of constrained material on its ballistic performance, the array structures with epoxy and 5083Al as constrained material were prepared for comparison. Ballistic performance tests were conducted using 12.7 mm Armor-Piercing Incendiary (API). The damage mechanisms of the armor structure were studied through finite element simulation and a combination of macroscopic and microscopic analyses. The results demonstrate excellent overall ballistic performance of the (SiCh-p + B4Cp)/5083Al armor system. The high-strength and high-toughness 55 vol%B4Cp/5083Al composite material exhibits strong interfacial bonding with SiCh-p, providing robust support to the SiCh-p. The armor back deformation was reduced by 50 %, and the ceramic layer dissipated more than 70 % of projectile kinetic energy, The materials prepared in this study exhibit significant potential in ballistic performance

Evolutionary History and Ongoing Transmission of Phylogenetic Sublineages of Mycobacterium tuberculosis Beijing Genotype in China.

&lt;p&gt;Mycobacterium tuberculosis Beijing genotype originated in China and has undergone a dramatic population growth and global spread in the last century. Here, a collection of M. tuberculosis Beijing family isolates from different provinces across all China was genotyped by high-resolution (24-MIRU-VNTR) and low-resolution, high-rank (modern and ancient sublineages) markers. The molecular profiles and global and local phylogenies were compared to the strain phenotype and patient data. The phylogeographic patterns observed in the studied collection demonstrate that large-scale (but not middle/small-scale) distance remains one of the decisive factors of the genetic divergence of M. tuberculosis populations. Analysis of diversity and network topology of the local collections appears to corroborate a recent intriguing hypothesis about Beijing genotype originating in South China. Placing our results within the Eurasian context suggested that important Russian B0/W148 and Asian/Russian A0/94-32 epidemic clones of the Beijing genotype could trace their origins to the northeastern and northwestern regions of China, respectively. The higher clustering of the modern isolates in children and lack of increased MDR rate in any sublineage suggest that not association with drug resistance but other (e.g., speculatively, virulence-related) properties underlie an enhanced dissemination of the evolutionarily recent, modern sublineage of the Beijing genotype in China.&lt;/p&gt;</p