Gravity,Quantum Fields and Quantum Information: Problems with Classical Channel and Stochastic Theories

In recent years an increasing number of papers have attempted to mimic or supplant quantum field theory in discussions of issues related to gravity by the tools and through the perspective of quantum information theory, often in the context of alternative quantum theories. In this article, we point out three common problems in such treatments. First, we show that the notion of interactions mediated by an information channel is not, in general, equivalent to the treatment of interactions by quantum field theory. When used to describe gravity, this notion may lead to inconsistencies with general relativity. Second, we point out that in general one cannot replace a quantum field by a classical stochastic field, or mock up the effects of quantum fluctuations by that of classical stochastic sources (noises), because in so doing important quantum features such as coherence and entanglement will be left out. Third, we explain how under specific conditions semi-classical and stochastic theories indeed can be formulated from their quantum origins and play a role at certain regimes of interest.     

Two-Particle Irreducible Effective Action in Gauge Theories

The goal of this paper is to develop the formalism of the two-particle irreducible (2PI) (G. Baym (1962). Physical Review 127, 1391; H. D. Dahmen and G. Jona Lasino (1962). Nuovo Cimento A 52, 807; C. de Dominicis and P. Martin (1964). Journal of Mathematical Physics 5, 14; J. Luttinger and J. Ward (1960). Physical Review 118, 1417; B. Vanderheyden and G. Baym (1998). Journal of Statistical Physics 98, 843; B. Vanderheyden and G. Baym (2000). In Progress in Nonequilibrium Green's Functions, World Scientific, Singapore). (or Cornwall–Jackiw–Tomboulis (CJT) (J. Cornwall, R. Jackiw, and E. Tomboulis (1974). Physical Review D 10, 2428; U. Kraemmer and A. Rebhan (2004). Reports on Progress in Physics 67, 351; R. Norton and J. Cornwall (1975). Annals of Physics 91, 106) effective action (EA) in a way appropiate to its application to nonequilibrium gauge theories. We hope this review article will stimulate new work into this field.     

Axiomatic Foundations of Galilean Quantum Field Theories

A realistic axiomatic formulation of Galilean Quantum Field Theories is presented, from which the most important theorems of the theory can be deduced. In comparison with others formulations, the formal aspect has been improved by the use of certain mathematical theories, such as group theory and the theory of rigged Hilbert spaces. Our approach regards the fields as real things with symmetry properties. The general structure is analyzed and contrasted with relativistic theories.On leave of absence from     

Nonlocal Hidden-Variable Theories and Quantum Mechanics: An Incompatibility Theorem

It is argued that among possible nonlocal hidden-variable theories a particular class (called here crypto-nonlocal or CN) is relatively plausible on physical grounds. CN theories have the property that (for example) the two photons emitted in an atomic cascade process are indistinguishable in their individual statistical properties from photons emitted singly, and that in the latter case the effects of nonlocality are unobservable. It is demonstrated that all CN theories are constrained by inequalities which are violated by the quantum-mechanical predictions; these inequalities bear no simple relation to Bell's inequalities, and an explicit example is constructed of a CN theory which violates the latter. It is also shown that while existing experiments cannot rule out general CN theories, they do rule out (subject to a few caveats such as the usual ones concerning the well-known loopholes) the subclass in which the photon polarizations are linear.     

Fock Theories and Quantum Logics

The notion of Fock theory is introduced in the framework of quantum logics, which are here orthomodular atomic lattices satisfying the covering property. It is shown that there are some fundamental facts concerning particles, which may be successfully discussed in this general context. One of these facts is to establish the theoretical conditions for considering particles as sharply defined entities. The other refers to the theoretical circumstances, which almost impose to consider that some particles have a structure, meaning they are composed from other particles. This last problem is strongly related with the conservative time evolutions.     

库的量子关联相干辅助系统能量提取的研究

基于单模微腔与二能级原子系综(库)构成的混合动力学模型,探索了非平衡库中量子关联相干(quantum correlated coherence, QCC)[Tan K C, et al. 2016 Phys. Rev. A 94, 022329])对系统动力学的影响.推导了量子关联相干库下系统演化的动力学方程.借助于含QCC的类GHZ库及其对应的参考库,清晰地揭示了非平衡库中QCC扮演着热力学资源的角色——能够有效辅助系统从库中提取更多能量.同时,结合解析与数值模拟方法研究了类GHZ库的有效温度和系统与库间的耦合参数对QCC能量效应的影响.研究发现, QCC对腔场的能量贡献不仅依赖于库的有效温度,而且也和系统与库间的耦合参数有关.这与二能级原子构成的传统的热库的情况(腔场从热库中提取的能量仅仅依赖于库的有效温度即二能级原子的热布局)完全不同.此外,研究发现QCC可视作一类优质的热力学资源,在特定条件下其对系统的能量贡献远大于原子热布局的贡献.因此, QCC将是高输出功率或高效率量子热机设计中的一类重要燃料.     

Feasibility of model ecosystems

Summary We introduce a structure with preferential trophic channels in a two-level Lotka-Volterra model. We discuss the dependence of feasibility on the number of species and on other properties of the system.

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Riassunto S'introduce una struttura con canali trofici preferenziali in un modello di Lotka-Volterra a due livelli. Si discute la dipendenza della realizzabilità del modello dal numero di specie e da altre proprietà del sistema.

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Резюме В двухуровневую модель Лотки-Вольтерра вводится структура с предпочтительными трофическими каналами. Мы обсуждаем влияние числа видов и других свойств системы на реализуемость модели.

     

Quantum Field Theories on an Algebraic Curve

We formulate quantum field theories on an algebraic curve and outline a 'paradigm' interpreting Ward identities as reciprocity laws.     

Charged black holes in the infinite derivative theory of gravity

The infinite derivative theory of gravity is a generalization of Einstein gravity with many interesting properties,but the black hole solutions in this theory are still not fully understood.In the paper,we concentrate on studying the charged black holes in such a theory.Adding the electromagnetic field part to the effective action,we show how the black hole solutions around the Reissner-Nordstrom metric can be solved perturbatively and iteratively.We further calculate the corresponding temperature,entropy and electrostatic potential of the black holes and verify the first law of thermodynamics.     

Deriving a differential equation for the spin-spin correlation in Ising systems

Summary The equipartition theorem and the high-temperature expansion are used to derive a differential equation for the spin-spin correlation in Ising systems. Some applications of this equation including improved upper bound on the three-dimensional transition temperature and correlation length are discussed. Due to the relevance of its scientific content, this paper has been given priority by the Journal Direction.     

大学物理实验在线教学及资源建设的思考

从大学物理实验教学在军队院校人才培养中的作用入手,深入分析了传统大学物理实验教学中存在的问题与根源,结合当前该校在线教学开展的成果,阐述了开展实验在线教学的必要性。最后,针对在线教学工作的关键:在线资源建设,根据实验课程的特点,给出了从实验人文史料、课程学习须知、基本实验方法、常见仪器使用、数据处理五个方面进行资源建设的设想。     

束流物理学的量子方法初探

量子束流物理学是近年来发展起来的处理束流传输的全新方法,它是经典束流物理学的有益补充。介绍了量子束流物理学的热波模型和基于狄拉克方程的相对论电子束磁透镜量子理论,并与经典束流物理学方法进行了比较。     

工科量子物理教学初探

工科量子物理教学可以通过压缩早期量子论的内容,全面介绍基本假设,并强调其联系来加强,同时通过精选内容、简化数学,以降低教学的难度.     

光的量子相干性与光频率的超精密测量--2005年诺贝尔物理学奖评述

2005年的诺贝尔物理学奖授予了现代光学领域的科学家，其中诺贝尔奖的一半授予了哈佛大学的Roy J．Glauber教授，以表彰他在光的量子相干性理论方面的突出贡献，诺贝尔奖的另外一半授予了美国科罗拉多大学与美国国家标准技术研究院联合实验（JILA）的John L．Hall教授和德国慕尼黑大学教授、马克斯普朗克-量子光学研究所所长TheodorW．Hansch教授，以表彰他们在光的超高精密测量方面的突出贡献，文章介绍了三位诺贝奖得主的贡献及其意义．     

Twisted Gauge Theories

Gauge theories on a space-time that is deformed by the Moyal–Weyl product are constructed by twisting the coproduct for gauge transformations. This way a deformed Leibniz rule is obtained, which is used to construct gauge invariant quantities. The connection will be enveloping algebra valued in a particular representation of the Lie algebra. This gives rise to additional fields, which couple only weakly via the deformation parameter θ and reduce in the commutative limit to free fields. Consistent field equations that lead to conservation laws are derived and some properties of such theories are discussed.     

简单体系温度涨落的发散问题

平衡体系热力学推导涨落的前提是涨落必须很小，如果得到一个发散的结果说明这一涨落是不可靠的.对一些体系温度涨落的热力学结果，在温度趋于绝对零度时是发散的，这时必须用统计物理来处理.对这些体系进行统计物理处理的结果表明，涨落在温度趋于绝对零度时是趋于零的. 关键词： 热力学与统计物理 涨落     

On the quantization of general relativity in anholonomic variables

In discussing Bohr-Sommerfeld-like quantum rules for gravity, it is argued that Einstein's Riemannian theory of general relativity rather leads to a quantum field-mechanics than to a quantum-field theory of gravity. We construct the canonically conjugate coordinates and momenta of this gravito-dynamics in the framework of the Einstein-Cartan teleparallelism.     

Two dimensional gauge theories revisited

Two dimensional quantum Yang-Mills theory is reexamined using a non-abelian version of the Duistermaat-Heckman integration formula to carry out the functional integral. This makes it possible to explain properties of the theory that are inaccessible to standard methods and to obtain general expressions for intersection pairings on moduli spaces of flat connections on a two dimensional surface. The latter expressions agree, for gauge group SU (2), with formulas obtained recently by several methods.     

光的量子相干性与光频率的超精密测量*——2005年诺贝尔物理学奖评述

2005年的诺贝尔物理学奖授予了现代光学领域的科学家,其中诺贝尔奖的一半授予了哈佛大学的Roy J. Glauber教授,以表彰他在光的量子相干性理论方面的突出贡献,诺贝尔奖的另外一半授予了美国科罗拉多大学与美国国家标准技术研究院联合实验室（JILA）的John L. Hall教授和德国慕尼黑大学教授、马克斯普朗克－量子光学研究所所长Theodor W. Hnsch教授, 以表彰他们在光的超高精密测量方面的突出贡献.文章介绍了三位诺贝奖得主的贡献及其意义.