检索结果-内蒙古大学图书馆

Carrier-envelope-phase effect on laser-driven bound-bound transitions in the high-frequency region

Physical Review A 2012年第4期86卷 043432-043432页

作者： Zhen Zhai Dian Peng Xi Zhao Fuming Guo Yujun Yang Panming Fu Jing Chen Zong-Chao Yan Bingbing Wang Laboratory of Optical Physics Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China Institute of Atomic and Molecular Physics Jilin University Changchun 130012 China Key Laboratory of High Energy Density Physics Simulation CAPT Peking University Beijing 100084 China Institute of Applied Physics and Computational Mathematics P. O. Box 8009 Beijing 100088 China Department of Physics University of New Brunswick Fredericton New Brunswick Canada E3B 5A3

We study the carrier-envelope-phase (CEP) effect of a few-cycle laser pulse on bound-bound transitions in helium in the high-frequency region. Specifically, for the one-photon transition from the 11S to the 21P state, the CEP effect increases as the frequency increases; while for the two-photon transition from the 11S to the 31D state, the CEP effect shows a peak at a frequency that is almost equal to the energy difference between the 11S and 31D states. By using a four-level model, we find that the CEP effect on the 11S–21P transition is attributed to the quantum interference between the positive-frequency and negative-frequency subpaths of the one-photon transition; whereas the CEP effect on the 11S–31D transition is attributed to the interference between the sum-frequency and difference-frequency components of the two-photon transition. These results indicate that the CEP effect can occur not only due to the interference between neighboring multiphoton-transition paths, but also due to the interference between two components inside one multiphoton-transition path. Therefore, this work, together with our previous work for the low-frequency region [Peng et al., Phys. Rev. A 82, 053407 (2010)], may provide a complete picture of the CEP effect on bound-bound transitions in the whole range of laser frequency.

关键词： Photons

来源：评论

学校读者我要写书评

暂无评论

Microstructural degeneracy associated with a two-point correlation function and its information content

引用

Physical Review E 2012年第5期85卷 051140-051140页

作者： C. J. Gommes Y. Jiao S. Torquato Department of Chemical Engineering University of Liège Liège 4000 Belgium Department of Chemistry Princeton University Princeton New Jersey 08544 USA Department of Physics Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA Princeton Center for Theoretical Science Princeton University Princeton New Jersey 08544 USA Princeton Institute for the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA

A two-point correlation function provides a crucial yet an incomplete characterization of a microstructure because distinctly different microstructures may have the same correlation function. In an earlier Letter [Gommes, Jiao, and Torquato, Phys. Rev. Lett. 108, 080601 (2012)], we addressed the microstructural degeneracy question: What is the number of microstructures compatible with a specified correlation function? We computed this degeneracy, i.e., configurational entropy, in the framework of reconstruction methods, which enabled us to map the problem to the determination of ground-state degeneracies. Here, we provide a more comprehensive presentation of the methodology and analyses, as well as additional results. Since the configuration space of a reconstruction problem is a hypercube on which a Hamming distance is defined, we can calculate analytically the energy profile of any reconstruction problem, corresponding to the average energy of all microstructures at a given Hamming distance from a ground state. The steepness of the energy profile is a measure of the roughness of the energy landscape associated with the reconstruction problem, which can be used as a proxy for the ground-state degeneracy. The relationship between this roughness metric and the ground-state degeneracy is calibrated using a Monte Carlo algorithm for determining the ground-state degeneracy of a variety of microstructures, including realizations of hard disks and Poisson point processes at various densities as well as those with known degeneracies (e.g., single disks of various sizes and a particular crystalline microstructure). We show that our results can be expressed in terms of the information content of the two-point correlation functions. From this perspective, the a priori condition for a reconstruction to be accurate is that the information content, expressed in bits, should be comparable to the number of pixels in the unknown microstructure. We provide a formula to calculate the

关键词： Microstructure

来源：评论

学校读者我要写书评

暂无评论

Covariant density functional theory for exotic nuclei near the neutron drip-line

引用

Journal of physics: Conference Series 2013年第1期413卷

作者： Y Chen L L Li Z P Li H Z Liang W H Long P Ring N Van Giai J M Yao S Q Zhang Y Zhang P W Zhao S G Zhou J Meng State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Beijing 100871 China Beijing Institute of Applied Physics and Computational Mathematics Beijing 100088 China School of Physics Science and Technology Southwest University Chongqing 400715 China School of Nuclear Science and Technology Lanzhou University Lanzhou 730000 China Physik Department Technische Universitä München D-85748 Garching Germany Institut de Physique Nucléaire IN2P3-CNRS and Université Paris-Sud 91406 Orsay France State Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 730000 China School of Physics and Nuclear Energy Engineering Beihang University Beijing 100191 China Department of Physics University of Stellenbosch Stellenbosch 7602 South Africa

The covariant density functional theory with a few number of parameters allows a very successful description of ground-state and excited-state properties for nuclei all over the nuclear chart. The recent progress on the covariant density functional theory and its applications for nuclear structure and astrophysics as well as extensions by the Beijing group and collaborators are summarized. In particular, the halos in exotic nuclei are discussed in details.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Optical shock and blow-up of ultrashort pulses in transparent media

引用

Physical Review A 2012年第3期86卷 033806-033806页

作者： P. Whalen J. V. Moloney A. C. Newell K. Newell M. Kolesik Program in Applied Mathematics University of Arizona Tucson AZ 85721-0089 USA Arizona Center for Mathematical Sciences University of Arizona Tucson AZ 85721-0089 USA Department of Mathematics University of Arizona Tucson AZ 85721-0089 USA College of Optical Sciences University of Arizona Tucson AZ 85721-0089 USA Department of Physics Constantine the Philosopher University Nitra 94974 Slovakia

Ultrashort pulses can exhibit two distinctive types of singularity: self-focusing collapse and self-steepening shock. We examine various ultrashort pulse propagation models and their relative effectiveness in explaining these phenomena. In particular, the modified Kadomtsev-Petviashvilli equation of type 1 (MKP1) is examined in some detail. We show that MKP1 is not simply a few-cycle pulse model but is valid in a more general broad spectrum setting. Furthermore, we emphasize that the dispersion of the MKP1 model can result in poor estimation of frequency-dependent phenomena, such as harmonic generation, which occur far away from the carrier frequency. Some of this loss of accuracy can be removed by using a more general MKP1 dispersion relation.

关键词： Ultrashort pulses

来源：评论

学校读者我要写书评

暂无评论

Phase synchronization of bursting neurons in clustered small-world networks

引用

Physical Review E 2012年第1期86卷 016211-016211页

作者： C. A. S. Batista E. L. Lameu A. M. Batista S. R. Lopes T. Pereira G. Zamora-López J. Kurths R. L. Viana Graduate Program in Physics State University of Ponta Grossa Ponta Grossa Paraná Brazil Departament of Mathematics and Statistics State University of Ponta Grossa Ponta Grossa Paraná Brazil Departament of Physics Federal University of Parana Curitiba Paraná Brazil Department of Mathematics Imperial College London London SW7 2AZ United Kingdom Bernstein Center for Computational Neuroscience Berlin Germany Department of Physics Humboldt University Berlin Germany Institute for Complex Systems and Mathematical Biology Aberdeen Scotland Potsdam Institute for Climate Impact Research Potsdam Germany

We investigate the collective dynamics of bursting neurons on clustered networks. The clustered network model is composed of subnetworks, each of them presenting the so-called small-world property. This model can also be regarded as a network of networks. In each subnetwork a neuron is connected to other ones with regular as well as random connections, the latter with a given intracluster probability. Moreover, in a given subnetwork each neuron has an intercluster probability to be connected to the other subnetworks. The local neuron dynamics has two time scales (fast and slow) and is modeled by a two-dimensional map. In such small-world network the neuron parameters are chosen to be slightly different such that, if the coupling strength is large enough, there may be synchronization of the bursting (slow) activity. We give bounds for the critical coupling strength to obtain global burst synchronization in terms of the network structure, that is, the probabilities of intracluster and intercluster connections. We find that, as the heterogeneity in the network is reduced, the network global synchronizability is improved. We show that the transitions to global synchrony may be abrupt or smooth depending on the intercluster probability.

关键词： Probability

来源：评论

学校读者我要写书评

暂无评论

Travelling wave solutions of a generalized Camassa-Holm-Degasperis-Procesi equation

引用

Science China mathematics 2011年第3期54卷 555-572页

作者： DENG ShengFu1, GUO BoLing2 & WANG TingChun2,3 1department of mathematics, Zhanjiang Normal University, Zhanjiang 524048, China 2Institute of applied physics and computational mathematics, Beijing 100088, China 3 College of Math and physics, Nanjing University of Information Science and Technology, Nanjing 210044, China Department of Mathematics Zhanjiang Normal University Zhanjiang China Institute of Applied Physics and Computational Mathematics Beijing China College of Math and Physics Nanjing University of Information Science and Technology Nanjing China

The travelling wave solutions of a generalized Camassa-Holm-Degasperis-Procesi equation ut-uxxt + (1 + b)umux = buxuxx + uuxxx are considered where b > 1 and m are positive integers. The qualitative analysis methods of planar autonomous systems yield its phase portraits. Its soliton wave solutions, kink or antikink wave solutions, peakon wave solutions, compacton wave solutions, periodic wave solutions and periodic cusp wave solutions are obtained. Some numerical simulations of these solutions are also given.

关键词： homoclinic orbits heteroclinic orbits peakon wave solutions compacton wave solutions periodic cusp wave solutions

来源：评论

学校读者我要写书评

暂无评论

Halos in a deformed relativistic Hartree-Bogoliubov theory in continuum

引用

AIP Conference Proceedings 2012年第1期1491卷 208-213页

作者： Lulu Li Jie Meng P. Ring En-Guang Zhao Shan-Gui Zhou Institute of Applied Physics and Computational Mathematics Beijing 100094 China State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Beijing 100871 China and Department of Physics University of Stellenbosch Stellenbosch South Africa Physikdepartment Technische Universität München 85748 Garching Germany and State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Beijing 100871 China State Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China and Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 730000 China

In this contribution we present some recent results about neutron halos in deformed nuclei. A deformed relativistic Hartree-Bogoliubov theory in continuumhas been developed and the halo phenomenon in deformed weakly bound nuclei is investigated. These weakly bound quantum systems present interesting examples for the study of the interdependence between the deformation of the core and the particles in the halo. Magnesium and neon isotopes are studied and detailed results are presented for the deformed neutron-rich and weakly bound nuclei 42Mg . The core of this nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the existence of halos in deformed nuclei and for the occurrence of this decoupling effect are discussed.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Semi-Eulerian and High Order Gaussian Beam Methods for the Schrödinger Equation in the Semiclassical Regime

引用

Communications in computational physics 2011年第3期9卷 668-687页

作者： Shi Jin Hao Wu Xu Yang Department of Mathematics University of WisconsinMadisonWI 53706USA Department of Mathematical Sciences Tsinghua UniversityBeijing 10084China Program in Applied and Computational Mathematics Princeton UniversityNJ 08544USA

A novel Eulerian Gaussian beam method was developed in[8]to compute the Schrödinger equation efficiently in the semiclassical *** this paper,we introduce an efficient semi-Eulerian implementation of this *** new algorithm inherits the essence of the Eulerian Gaussian beam method where the Hessian is computed through the derivatives of the complexified level set functions instead of solving the dynamic ray tracing *** difference lies in that,we solve the ray tracing equations to determine the centers of the beams and then compute quantities of interests only around these *** yields effectively a local level set implementation,and the beam summation can be carried out on the initial physical space instead of the phase *** a consequence,it reduces the computational cost and also avoids the delicate issue of beam summation around the caustics in the Eulerian Gaussian beam ***,the semi-Eulerian Gaussian beam method can be easily generalized to higher order Gaussian beam methods,which is the topic of the second part of this *** numerical examples are provided to verify the accuracy and efficiency of both the first order and higher order semi-Eulerian methods.

关键词： Schrödinger equation semi-Eulerian Gaussian beam method high order methods

来源：评论

学校读者我要写书评

暂无评论

Theoretical analysis of electronic and magnetic properties of NaV2O4: Crucial role of the orbital degrees of freedom

引用

Physical Review B 2012年第10期86卷 104409-104409页

作者： Z. V. Pchelkina I. V. Solovyev R. Arita Institute of Metal Physics Russian Academy of Sciences-Ural Division 620990 Ekaterinburg Russia Theoretical Physics and Applied Mathematics Department Ural Federal University Mira Str. 19 620002 Ekaterinburg Russia Computational Materials Science Unit National Institute for Materials Science 1-2-1 Sengen Tsukuba Ibaraki 305-0047 Japan Department of Applied Physics Graduate School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan PRESTO Japan Science and Technology Agency 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan

Using a realistic low-energy model with parameters derived from the first-principles electronic structure calculation, we address the origin of the quasi-one-dimensional behavior in orthorhombic NaV2O4, consisting of the double chains of edge-sharing VO6 octahedra. We argue that the geometrical aspect alone does not explain the experimentally observed anisotropy of electronic and magnetic properties of NaV2O4. Instead, we attribute the unique behavior of NaV2O4 to one particular type of the orbital ordering, which respects the orthorhombic Pnma symmetry. This orbital ordering acts to divide all t2g states into two types: The “localized” ones, which are antisymmetric with respect to the mirror reflection y→−y, and the symmetric “delocalized” ones. Thus, NaV2O4 can be classified as the double exchange system. The directional orientation of symmetric orbitals, which form the metallic band, appears to be sufficient to explain both quasi-one-dimensional character of interatomic magnetic interactions and the anisotropy of electrical resistivity.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Inclusive Proton Energy Spectra of the Deuteron Induced Reaction

引用

Chinese physics Letters 2011年第11期28卷 87-90页

作者： WANG Jia YE Tao SUN Wei-Li Yukinobu Watanabe Kazuyuki Ogata Institute of Applied Physics and Computational Mathematics Beijing 100094 Department of Advanced Energy Engineering Science Kyushu UniversityFukuoka 816-8580Japan Research Center for Nuclear Physics Osaka UniversityIbarakiOsaka 567-0047Japan

The continuum-discritized coupled channel method and the glauber model are applied for the description of deuteron elastic breakup and the stripping processes,*** with the conventional two-component exciton model for pre-equilibrium processes and the Hauser-Feshbach theory for compound process,an approach based on models is proposed to analyze the inclusive proton energy spectra of a deuteron-induced *** contributions from each process to the energy spectra of the 58Ni(d,xp)reaction are quantitatively *** results show that this approach is able to reasonably reproduce the experimental data of the double differential cross sections,energy spectra and cross sections,although further improvements are needed.

关键词： reaction spectra stripping

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：