Double Structures and Soliton Double Solution Family for Einstein-Maxwell-Dilaton Theory

A doubleness symmetry property of the two-dimensional reduced Einstein-Maxwell-dilaton theory is found and, by using the so-called extended double complex method proposed previously, the motion equations of the theory are extended into a double form. Some new double symmetry transformations and double solution generating methods are given. As applications of these transformations and methods, an infinite chain of double solutions and a new soliton double solution family of the model are obtained. These results demonstrate that the theory under consideration possesses more and richer symmetry structures than previously expected. It seems that some of these results can not be obtained by using only the usual (non-double) scheme.     

Double Complex (Anti-)self-dual Variables and a Related Double Action in Four-dimensional Gravity

In this paper double dual transformations anddouble complex (anti-)self-dual variables infour-dimensional gravity are given by using the doublecomplex function method. A double action with doublecomplex anti-self-dual variables is proposed, hence thedouble complex (anti-) self-dual gravitational theory isestablish. Finally, the analytic continuation from thedouble action to the Euclidean action is discussed, and some given results are here extended intoa double form.     

Double Structures and Double Symmetries for the Einstein-Maxwell-Dilaton-Axion Theory

By using the so-called double-complex function method, it is found that the stationary axisymmetric D = 4 Einstein-Maxwell-Dilaton-Axion system can be written in a double-complex matrix Ernst-like form. Then the double symmetry symplectic group Sp((4, R(J)) of the theory and its double-complex fractional linear realization are given. These results demonstrate that the theory considered possesses more and richer symmetry structures than previously expected. Moreover, as an application, an infinite chain of double-solutions of the problem is obtained, which shows that the double-complex method is more effective. Some of the results of this paper cannot be obtained by the usual (non-double) scheme.     

Double Layers and Circuits in Astrophysics

As the rate of energy release in a double layer with voltage ?V is P ? I?V, a double layer must be treated as a part of a circuit which delivers the current I. As neither double layer nor circuit can be derived from magnetofluid models of a plasma, such models are useless for treating energy transfer by means of double layers. They must be replaced by particle models and circuit theory. A simple circuit is suggested which is applied to the energizing of auroral particles, to solar flares, and to intergalactic double radio sources. Application to the heliospheric current systems leads to the prediction of two double layers on the sun's axis which may give radiations detectable from Earth. Double layers in space should be classified as a new type of celestial object (one example is the double radio sources). It is tentatively suggested that X-ray and ?-ray bursts may be due to exploding double layers (although annihilation is an alternative energy source). A study of how a number of the most used textbooks in astrophysics treat important concepts such as double layers, critical velocity, pinch effects, and circuits is made. It is found that students using these textbooks remain essentially ignorant of even the existence of these concepts, despite the fact that some of them have been well known for half a century (e.g., double layers, Langmuir, 1929; pinch effect, Bennet, 1934).     

Double field formulation of Yang-Mills theory

Based on our previous work on the differential geometry for the closed string double field theory, we construct a Yang-Mills action which is covariant under O(D,D) T-duality rotation and invariant under three-types of gauge transformations: non-Abelian Yang-Mills, diffeomorphism and one-form gauge symmetries. In double field formulation, in a manifestly covariant manner our action couples a single O(D,D) vector potential to the closed string double field theory. In terms of undoubled component fields, it couples a usual Yang-Mills gauge field to an additional one-form field and also to the closed string background fields which consist of a dilaton, graviton and a two-form gauge field. Our resulting action resembles a twisted Yang-Mills action.     

Persistent Currents in the Double Aharonov-Bohm Ring Connected to Electron Reservoirs

We study persistent currents in the double Aharonov-Bohm ring connected to two electron reservoirs by quantum waveguide theory. It is found that the persistent currents in the double Aharonov-Bohm ring depend on the direction of the current flow from one reservoir to another. When the direction of the current flow reverses, the persistent current in each ring of the double Aharonov-Bohm ring changes. If the two rings are of the same size, the persistent currents in the left and the right rings exchange at the reversal of the current flow direction.     

耦合谐振子的双波描述

采用双波函数量子理论 ,研究了耦合谐振子力学量的时间演化方程及其经典极限 ,进一步验证了双波函数描述的是单个粒子 ,而单个波函数描述的是量子系综的结论     

Double Wells

Schrödinger operators with interactions symmetric about a plane (double-well potentials) occur in several branches of physics, such as chemistry and quantum field theory. They commonly exhibit asymptotic eigenvalue degeneracy, i.e., pairs of eigenvalues coalesce as the potential wells get farther apart. After a sketch of the theory of double wells, it is shown that the problem of estimating the gap between two such eigenvalues is reducible to finding asymptotics of eigenfunctions. For several examples and classes of potentials the gap is estimated or bounded above and below. The general case is fullyn-dimensional.Much of this work was done with support of an NSF National Needs Fellowship at the Department of Mathematics, M.I.T.     

Double ionization of lithiumlike ions by Compton scattering of high-energy photons

The double ionization of lithiumlike ions by Compton scattering of photons is investigated in the asymptotic high-energy region. To leading order of the nonrelativistic perturbation theory, the total cross section for double Compton effect is calculated, taking into account the channels of simultaneous and sequential emission of two electrons. Relationships between the cross sections for double ionization of He- and Li-like ions with the same nuclear charge Z are established. This can open wide perspectives for experimental investigations of ionization processes involving low-lying excited states. The universal scaling is found for the ratio of double-to-single ionization in the lithium isoelectronic sequence.     

Noncontinuous Solitary Wave Solutions for Double sine-Gordon Equation

Using the tanh method and a variable separated ordinary difference equation method to solve the double sineGordon equation, we derive some new exact travelling wave solutions, especially a new type of noncontinuous solitary wave solutions. These noncontinuous solitary wave solutions are verified by using the conservation law theory.     

双波长双峰值比光度法测定配合物组成比的原理

文章建立了一种测定配合物组成比的简易方法。从理论上严格地推导了双波长双峰值比法测定配合物组成比的理论计算公式,并依据大量实验数据加以验正。计算值与传统方法值相吻合。从原理上和实验中证明该方法切实可行。     

硅基双势垒金属-绝缘层-金属-绝缘层-半导体隧道发光结

讨论了硅基双势垒金属－绝缘层－金属－绝缘层－半导体（MIMIS）隧道发光结的结构、制备方法及发光特性。所制备的样品最大发光亮度达到1．9cd/m^2、光谱的峰值波长移到了蓝绿光区，表明双势垒MIMIS隧道发光结的性能优于单势垒金属－绝缘层－半导体（MIS）隧道发光结。利用量子力学的共振隧穿效应对它作了较好的解释。     

Transient Intersubband Optical Absorption in Double Quantum Well Structure

The microscopic equations of motion including many-body effects are derived to study the intersubband polarization in the double quantum well structure induced by an ultrafast pumping infrared light. Based on the self-consistent field theory, the transient probe absorption coefficient is calculated. These calculations are beyond the previous steady-state assumption. Transient probe absorption spectra are calculated under different pumping intensity and various pump probe delay.     

Ion Beam Driven Ion Cyclotron Double Layers

We present here a self consistent theory of small amplitude double layers associated with electrostatic ion cyclotron waves in a plasma containing hot electrons, cold ions and traversed by an ion beam. It has been shown that compressive type of double layers solution exists when θ_b (beam temperature) < α_b (beam concentration) < 1.     

Double Bruhat Cells in Kac–Moody Groups and Integrable Systems

We construct a family of integrable Hamiltonian systems generalizing the relativistic periodic Toda lattice, which is recovered as a special case. The phase spaces of these systems are double Bruhat cells corresponding to pairs of Coxeter elements in the affine Weyl group. In the process we extend various results on double Bruhat cells in simple algebraic groups to the setting of Kac–Moody groups. We also generalize some fundamental results in Poisson–Lie theory to the setting of ind-algebraic groups, which is of interest beyond our immediate applications to integrable systems.     

Double sine-Gordon model revisited

We reconsider the mass spectrum of double sine-Gordon theory where recent semiclassical results called into question the previously accepted picture. We use the truncated conformal space approach (TCSA) to investigate the claims. We demonstrate that the numerics supports the original results, and strongly disagrees with those obtained from semiclassical soliton form factor techniques. Besides the numerical analysis, we also discuss the underlying theoretical arguments.     

Double Ramification Cycles and Quantum Integrable Systems

In this paper, we define a quantization of the Double Ramification Hierarchies of Buryak (Commun Math Phys 336:1085–1107, 2015) and Buryak and Rossi (Commun Math Phys, 2014), using intersection numbers of the double ramification cycle, the full Chern class of the Hodge bundle and psi-classes with a given cohomological field theory. We provide effective recursion formulae which determine the full quantum hierarchy starting from just one Hamiltonian, the one associated with the first descendant of the unit of the cohomological field theory only. We study various examples which provide, in very explicit form, new (1+1)-dimensional integrable quantum field theories whose classical limits are well-known integrable hierarchies such as KdV, Intermediate Long Wave, extended Toda, etc. Finally, we prove polynomiality in the ramification multiplicities of the integral of any tautological class over the double ramification cycle.     

Double exchange model for nanoscopic clusters

We solve the double exchange model on nanoscopic clusters exactly, and specifically consider a six-site benzene-like nanocluster. This simple model is an ideal testbed for studying magnetism in nanoclusters and for validating approximations such as the dynamical mean field theory (DMFT). Non-local correlations arise between neighboring localized spins due to the Hund’s rule coupling, favoring a short-range magnetic order of ferro or antiferromagnetic type. For a geometry with more neighboring sites or a sufficiently strong hybridization between leads and the nanocluster, these non-local correlations are less relevant, and DMFT can be applied reliably.     

A New Mechanism for Low Energy Pion Induced Double Charge Exchange Reaction

Using a method developed in theory of double beta decay[1], we propose a new mechanism, namely the two-nucleon pion absorption-emission mechanism for pion double charge exchange reaction at low energies. The calculations are compared with the experimental data of the angular distribution at 50 MeV and the 0° excitation functions of the DCX reactions on ¹⁴C, ¹⁸O with energies < 130 MeV. It is found that the contribution of this new mechanism is very important at low energies.     

Mode Control of Quasi-PT Symmetry in Laterally Multi-Mode Double Ridge Semiconductor Laser

In traditional semiconductor lasers, it is usual to obtain single lateral mode operation by narrowing the ridge of waveguide, which is sensitive to fabrication inaccuracies. To overcome this shortcoming, a quasi-PT(parity-time)symmetric double ridge semiconductor laser is proposed to reach single lateral mode operation for an intrinsic multi-mode stripe laser. The coupled mode theory is used to analyze the non-Hermitian modulation of the gain(or loss) of the PT symmetric double ridge laser to obtain the coupling coefficient between the two ridge waveguides. Finally, the mode field distributions of the quasi-PT symmetric double ridge laser are simulated before and after the spontaneous PT symmetry breaking, which keep the laser operating in single lateral mode.