The Institute of Applied Physics and Computational Mathematics was established in 1958 in Beijing in the People's Republic of China. The institution conducts research on nuclear warhead design computations for the Chinese Academy of Engineering Physics in Mianyang, Sichuan and focuses on applied theoretical research and on the study of fundamental theories. Its main research fields include: Theoretical Physics, Nuclear Fusion and Plasma Physics, Nuclear Physics and Atomic Molecular Physics, Laser Physics, Fluid Dynamics, Applied Mathematics, Computer Application, Computer Application, Arms Control Science and Technology. From August 2012, the director of the institute was LI Hua. Wikipedia.
Xu X.,CAS Beijing Institute of Applied Physics And Computational Mathematics
Nonlinear Analysis: Real World Applications | Year: 2017
This paper is concerned with the global existence and time-asymptotic behavior of solutions to the three dimensional complete electromagnetic fluid system (or Maxwell–Navier–Stokes equations) for viscous compressible fluids. The global classical solution is established when the initial data are small perturbations of some given constant state. Moreover, the optimal decay estimates of the solution in Lq with 2≤q≤6 and its higher-order spatial derivatives in L2 are also obtained. © 2016 Elsevier Ltd
Miao C.,CAS Beijing Institute of Applied Physics And Computational Mathematics |
Zheng X.,China Academy of Engineering Physics
Communications in Mathematical Physics | Year: 2013
In this paper, we investigate the Cauchy problem for the tridimensional Boussinesq equations with horizontal dissipation. Under the assumption that the initial data is axisymmetric without swirl, we prove the global well-posedness for this system. In the absence of vertical dissipation, there is no smoothing effect on the vertical derivatives. To make up this shortcoming, we first establish a magic relationship between ur/r and ωtheta/r by taking full advantage of the structure of the axisymmetric fluid without swirl and some tricks in harmonic analysis. This together with the structure of the coupling of (1.2) entails the desired regularity. © 2013 Springer-Verlag Berlin Heidelberg.
Xin Z.,Chinese University of Hong Kong |
Yan W.,CAS Beijing Institute of Applied Physics And Computational Mathematics
Communications in Mathematical Physics | Year: 2013
In this paper, we study the finite time blow up of smooth solutions to the Compressible Navier-Stokes system when the initial data contain vacuums. We prove that any classical solutions of viscous compressible fluids without heat conduction will blow up in finite time, as long as the initial data has an isolated mass group (see Definition 2.2). The results hold regardless of either the size of the initial data or the far fields being vacuum or not. This improves the blowup results of Xin (Comm Pure Appl Math 51:229-240, 1998) by removing the crucial assumptions that the initial density has compact support and the smooth solution has finite total energy. Furthermore, the analysis here also yields that any classical solutions of viscous compressible fluids without heat conduction in bounded domains or periodic domains will blow up in finite time, if the initial data have an isolated mass group satisfying some suitable conditions. © 2012 Springer-Verlag Berlin Heidelberg.
Zhang W.,CAS Beijing Institute of Applied Physics And Computational Mathematics |
Govorov A.O.,Ohio University
Physical Review B - Condensed Matter and Materials Physics | Year: 2011
We develop a quantum theory of the field-tunable nonlinear Fano effect in the hybrid metal-semiconductor nanostructures, in which the plasmon (semicontinuous collective intraband excitation) and the exciton (discrete single-particle interband excitation) are treated on the same footing. Our quantum theory shows that the quantum interference due to the plasmon-exciton interaction leads to the nonlinear Fano effect described by a generalized complex field-tunable Fano factor for the systems with strong external field and dephasing. We establish the relation between quantum and semiclassical theories and show that the results of the quantum and semiclassical theories differ both qualitatively and quantitatively in the strongly nonlinear regime-in particular, the quantum theory predicts the absence of nonlinear instability in the hybrid systems with plasmon relaxation. © 2011 American Physical Society.
Zhao L.-C.,CAS Beijing Institute of Applied Physics And Computational Mathematics |
Zhao L.-C.,Hefei University of Technology
Annals of Physics | Year: 2013
We study rogue waves of Bose-Einstein condensate (BEC) analytically in a time-dependent harmonic trap with a complex potential. Properties of the nonautonomous rogue waves are investigated analytically. It is reported that there are possibilities to 'catch' rogue waves through manipulating nonlinear interaction properly. The results provide many possibilities to manipulate rogue waves experimentally in a BEC system. © 2012 Elsevier Inc.
Chang L.,CAS Beijing Institute of Applied Physics And Computational Mathematics |
Luo S.,CAS Academy of Mathematics and Systems Science
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013
The geometric discord, as introduced by Dakić, Vedral, and Brukner, is a significant figure of merit for quantum correlations with wide applications. However, it has a curious drawback in that it may change reversibly by trivially adding a local ancilla, as recently criticized by Piani. This casts doubt on the information content and usage of geometric discord. In this work, we show that this problem with geometric discord can be remedied simply by starting from the square root of a density operator, rather than the density operator itself, in defining the discord. Moreover, most other basic properties and analytical aspects of the original geometric discord can be carried over to this modified discord. Due to the square-root character, which is reminiscent of probability amplitudes ubiquitous in quantum theory, the modified discord seems to capture quantum correlations in a more intrinsic and informational fashion. © 2013 American Physical Society.
Jiang F.,CAS Beijing Institute of Applied Physics And Computational Mathematics
Nonlinear Analysis: Real World Applications | Year: 2011
In [A. Jngel, Global weak solutions to compressible NavierStokes equations for quantum fluids, SIAM J. Math. Anal. 42 (2010) 10251045], Jngel proved the global existence of the barotropic compressible quantum NavierStokes equations for when the viscosity constant is bigger than the scaled Planck constant. Recently, Dong [J. Dong, A note on barotropic compressible quantum NavierStokes equations, Nonlinear Anal. TMA 73 (2010) 854856] extended Jngel's result to the case where the viscosity constant is equal to the scaled Planck constant by using a new estimate of the square root of the solutions. In this paper we show that Jngel's existence result still holds when the viscosity constant is bigger than the scaled Planck constant. Consequently, with our result, the existence for all physically interesting cases of the scaled Planck and viscosity constants is obtained. © 2010 Elsevier Ltd. All rights reserved.
Chang L.,CAS Beijing Institute of Applied Physics And Computational Mathematics
Journal of Computational Physics | Year: 2014
A new reconstruction algorithm is developed to obtain diffusion schemes with cell-centered unknowns only. The main characteristic of the new algorithm is the flexibility of stencils when the auxiliary unknowns are reconstructed with cell-centered unknowns. The stencils are selected depending on the mesh geometry and discontinuities of diffusion coefficients. Moreover, an explicit expression is derived for interpolating the auxiliary unknowns in terms of cell-centered unknowns, and the auxiliary unknowns can be defined at any point on the edge. The algorithm is applied to construct several new diffusion schemes, whose effectiveness is illustrated by numerical experiments. For anisotropic problems with or without discontinuities, nearly second order accuracy is achieved on skewed meshes. © 2013 Elsevier Inc.
Zhang M.,CAS Beijing Institute of Applied Physics And Computational Mathematics
Journal of Computational Physics | Year: 2010
The methods for simulating surface tension with smoothed particle hydrodynamics (SPH) method in two dimensions and three dimensions are developed. In 2D surface tension model, the SPH particle on the boundary in 2D is detected dynamically according to the algorithm developed by Dilts [G.A. Dilts, Moving least-squares particle hydrodynamics II: conservation and boundaries, International Journal for Numerical Methods in Engineering 48 (2000) 1503-1524]. The boundary curve in 2D is reconstructed locally with Lagrangian interpolation polynomial. In 3D surface tension model, the SPH particle on the boundary in 3D is detected dynamically according to the algorithm developed by Haque and Dilts [A. Haque, G.A. Dilts, Three-dimensional boundary detection for particle methods, Journal of Computational Physics 226 (2007) 1710-1730]. The boundary surface in 3D is reconstructed locally with moving least squares (MLS) method. By transforming the coordinate system, it is guaranteed that the interface function is one-valued in the local coordinate system. The normal vector and curvature of the boundary surface are calculated according to the reconstructed boundary surface and then surface tension force can be calculated. Surface tension force acts only on the boundary particle. Density correction is applied to the boundary particle in order to remove the boundary inconsistency. The surface tension models in 2D and 3D have been applied to benchmark tests for surface tension. The ability of the current method applying to the simulation of surface tension in 2D and 3D is proved. © 2010 Elsevier Inc.
Cheng T.,CAS Beijing Institute of Applied Physics And Computational Mathematics
Computers and Geosciences | Year: 2013
Kriging algorithms are a group of important interpolation methods, which are very useful in many geological applications. However, the algorithm based on traditional general purpose processors can be computationally expensive, especially when the problem scale expands. Inspired by the current trend in graphics processing technology, we proposed an efficient parallel scheme to accelerate the universal Kriging algorithm on the NVIDIA CUDA platform. Some high-performance mathematical functions have been introduced to calculate the compute-intensive steps in the Kriging algorithm, such as matrix-vector multiplication and matrix-matrix multiplication. To further optimize performance, we reduced the memory transfer overhead by reconstructing the time-consuming loops, specifically for the execution on GPU. In the numerical experiment, we compared the performances among different multi-core CPU and GPU implementations to interpolate a geological site. The improved CUDA implementation shows a nearly 18× speedup with respect to the sequential program and is 6.32 times faster compared to the OpenMP-based version running on Intel Xeon E5320 quad-cores CPU and scales well with the size of the system. © 2012 Elsevier Ltd.