A strange weak value in spontaneous pair productions via a supercritical step potential

We consider a case where a weak value is introduced as a physical quantity rather than an average of weak measurements. The case we treat is a time evolution of a particle by 1+1 dimensional Dirac equation. Particularly in a spontaneous pair production via a supercritical step potential, a quantitative explanation can be given by a weak value for the group velocity of the particle. We also show the condition for the pair production (supercriticality) corresponds to the condition when the weak value takes a strange value (superluminal velocity).Comment: 12 pages, 3 figures, close to published versio

Electron-positron pairs in physics and astrophysics: from heavy nuclei to black holes

From the interaction of physics and astrophysics we are witnessing in these years a splendid synthesis of theoretical, experimental and observational results originating from three fundametal physical processes. They were originally proposed by Dirac, by Breit and Wheeler and by Sauter, Heisenberg, Euler and Schwinger. The vacuum polarization process in strong electromagnetic field, pioneered by Sauter, Heisenberg, Euler and Schwinger, introduced the concept of critical electric field. It has been searched without success for more than forty years by heavy-ion collisions in many of the leading particle accelerators worldwide. The novel situation today is that these same processes can be studied on a much more grandiose scale during the gravitational collapse leading to the formation of a black hole being observed in Gamma Ray Bursts. This report is dedicated to the scientific race in act. The theoretical and experimental work developed in Earth-based laboratories is confronted with the theoretical interpretation of space-based observations of phenomena originating on cosmological scales. What has become clear in the last ten years is that all the three above mentioned processes, duly extended in the general relativistic framework, are necessary for the understanding of the physics of the gravitational collapse to a black hole. Vice versa, the natural arena where these processes can be observed in mutual interaction and on an unprecedented scale, is indeed the realm of relativistic astrophysics.Comment: to appear in Physics Reports, corrected proof

FIAS Scientific Report 2011

In the year 2010 the Frankfurt Institute for Advanced Studies has successfully continued to follow its agenda to pursue theoretical research in the natural sciences. As stipulated in its charter, FIAS closely collaborates with extramural research institutions, like the Max Planck Institute for Brain Research in Frankfurt and the GSI Helmholtz Center for Heavy Ion Research, Darmstadt and with research groups at the science departments of Goethe University. The institute also engages in the training of young researchers and the education of doctoral students. This Annual Report documents how these goals have been pursued in the year 2010. Notable events in the scientific life of the Institute will be presented, e.g., teaching activities in the framework of the Frankfurt International Graduate School for Science (FIGSS), colloquium schedules, conferences organized by FIAS, and a full bibliography of publications by authors affiliated with FIAS. The main part of the Report consists of short one-page summaries describing the scientific progress reached in individual research projects in the year 2010..

Strong-Field Physics in QED and QCD: From Fundamentals to Applications

We provide a pedagogical review article on fundamentals and applications of the quantum dynamics in strong electromagnetic fields in QED and QCD. The fundamentals include the basic picture of the Landau quantization and the resummation techniques applied to the class of higher-order diagrams that are enhanced by large magnitudes of the external fields. We then discuss observable effects of the vacuum fluctuations in the presence of the strong fields, which consist of the interdisciplinary research field of nonlinear QED. We also discuss extensions of the Heisenberg-Euler effective theory to finite temperature/density and to non-Abelian theories with some applications. Next, we proceed to the paradigm of the dimensional reduction emerging in the low-energy dynamics in the strong magnetic fields. The mechanisms of superconductivity, the magnetic catalysis of the chiral symmetry breaking, and the Kondo effect are addressed from a unified point of view in terms of the renormalization-group method. We provide an up-to-date summary of the lattice QCD simulations in magnetic fields for the chiral symmetry breaking and the related topics as of the end of 2022. Finally, we discuss novel transport phenomena induced by chiral anomaly and the axial-charge dynamics. Those discussions are supported by a number of appendices.Comment: Prepared for an invited review article; Published versio

Proceedings of RIKEN BNL Research Center Workshop: New Horizons for Lattice Computations with Chiral Fermions

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En route to the industrial applications of ionic liquids for metal oxide production and biomass fractionation: A sustainable avenue to advanced materials

In the context of climate change, it is essential to use renewable materials and to reduce the environmental footprint of industrial processes. This work focuses on the feasibility of implementing a low-cost Ionic Liquid (IL) in a large-scale biorefinery for bioethanol production (the ionoSolv process). The selected feedstock was Eucalyptus red grandis, a fast-growing hardwood. The lignocellulosic biomass was fractionated at laboratory scale, using aqueous N,N,N-trimethylammonium hydrogen sulfate (20 wt% water), at different temperatures and reaction times, to maximize glucose recovery (86%). Experiments under CO2 atmospheres (sub and supercritical) revealed that the ionoSolv process is pressure insensitive. A detailed Techno-Economic Analysis (TEA) for a biorefinery using the ionoSolv pretreatment was performed and compared to one using the acid-catalysed steam explosion pretreatment. With the ionoSolv pretreatment, the composition of the cellulose-rich pulps can be tailored and high-purity lignins can be recovered. The economic performance of both pretreatments are similar. From a sustainability perspective there are trade-offs: the ionoSolv process consumes 25% more energy (with potential for optimization) but consumes less chemicals and produces less waste. These results indicate that this process can be a competitive alternative. During the development of this process, and other IL-based processes, the interaction of ILs (neat and aqueous) with metals was investigated to establish suitable materials of construction. It was observed that the corrosion behaviour of metals exposed to ILs is system dependent. Surprisingly, water can act either as a corrosion inhibitor or promoter. A semi-quantitative classification method for the different corrosion behaviours observed was developed. Some metals exposed to aqueous ILs formed particles, resulting in the inadvertent development of a novel process for metal-based materials at large-scale: Oxidative Ionothermal Synthesis (OIS). A high-level TEA suggests that OIS offers economic and environmentally advantageous production of bulk and advanced metal-based materials, such as zinc oxide.Open Acces

Nuclear Power

We are fortunate to live in incredibly exciting and incredibly challenging time. Energy demands due to economic growth and increasing population must be satisfied in a sustainable manner assuring inherent safety, efficiency and no or minimized environmental impact. These considerations are among the reasons that lead to serious interest in deploying nuclear power as a sustainable energy source. At the same time, catastrophic earthquake and tsunami events in Japan resulted in the nuclear accident that forced us to rethink our approach to nuclear safety, design requirements and facilitated growing interests in advanced nuclear energy systems. This book is one in a series of books on nuclear power published by InTech. It consists of six major sections housing twenty chapters on topics from the key subject areas pertinent to successful development, deployment and operation of nuclear power systems worldwide. The book targets everyone as its potential readership groups - students, researchers and practitioners - who are interested to learn about nuclear power

Cellulose

Cellulose is only one of the components of biomass, although being the most abundant. To make useful chemicals or materials from cellulose requires as the first step the separation of cellulose from biomass. Various issues of cellulose extraction and its conversion are discussed in the chapters of this book on cellulose, the third and last one of a series of books on cellulose. This conversion of cellulose is an integral part of the biorefinery concept, an effort to derive optimum value from all biomass components, and as such compulsory reading for students and researchers in this area

Nuclear Power - Deployment, Operation and Sustainability

We are fortunate to live in incredibly exciting and incredibly challenging time. Energy demands due to economic growth and increasing population must be satisfied in a sustainable manner assuring inherent safety, efficiency and no or minimized environmental impact. These considerations are among the reasons that lead to serious interest in deploying nuclear power as a sustainable energy source. At the same time, catastrophic earthquake and tsunami events in Japan resulted in the nuclear accident that forced us to rethink our approach to nuclear safety, design requirements and facilitated growing interests in advanced nuclear energy systems. This book is one in a series of books on nuclear power published by InTech. It consists of six major sections housing twenty chapters on topics from the key subject areas pertinent to successful development, deployment and operation of nuclear power systems worldwide. The book targets everyone as its potential readership groups - students, researchers and practitioners - who are interested to learn about nuclear power