学术报告:Wave Packet Molecular Dynamics Simulations of Fermionic Systems
报 告 人:Ilya Valuev(Joint Institute for High Temperatures of Russian Academy of Sciences)
报告时间:2014年6月18日(星期三)上午10:00-11:00
报告地点:嘉定园区学术活动中心307
报告简介:
In this talk an introduction to the method of Wave Packet Molecular Dynamics Method (WPMD) will be given. The method is used in the dynamic simulations of many body quantum systems. It may be considered as a robust mapping of the quantum many body problem onto a set of "classical" equations of motion with fixed number of dynamic variables. For the fermionic systems the antisymmetrized version of WPMD (AWPMD) allows one to construct a trial many- body wavefunction taking particle spins into account. The Floating Multiple Gaussians Basis is an effective basis for expansion of the trial wave function for the numerical quantum dynamics. For example, in the Split Wave Packets Molecular Dynamics method single electron wave functions are expanded in a set of Gaussian wave packets. The Gaussians are called floating because their parameters (positions, momenta, etc.) are treated as dynamical variables.
A brief description of the method theory and its recent modifications will be given. The split-packet version of WPMD will be discussed, where each electron is represented by multiple Gaussians, with mixing coefficients playing the role of additional dynamic variables.
The numerical algorithms and techniques of the AWPMD dynamics, including the treatment of degenerate norm matrix and variable time stepping will be analyzed. The current implementation of the AWPMD algorithm as a C++ class library and the code structure will be outlined. Computational details and the implementation of AWPMD into the LAMMPS code will be presented briefly.
The AWMPD method has a range of applications form elementary processes in nuclear matter, collisions of small atoms and molecules, interaction with laser radiation to the extended system such as warm dense matter. We will discuss the existing test cases and results obtained so far with the method. An outlook for the method development will be given, including possible increase of the accuracy and work with quantum correct boundary conditions.
报告人简介:
Ilya Valuev was born 20 December 1972 in Moscow. In 1996 he graduated the Moscow Institute of Physics and Technology, Department of Molecular and Biological Physics. He started his scientific work as a research fellow in Humboldt University of Berlin in 1997-2001 and at the same time as PhD student in the Moscow Institute of Physics and Technology. In 2002, after one year of self-employment and work for Schlumberger Company as field engineer, he continued his scientific career as a researcher in the Joint Institute for High Temperatures of Russian Academy of Sciences (JIHT RAS), were he works until present time as senior researcher. In 2011 Ilya Valuev defended his Ph.D. thesis on the topic “Effect of the surface curvature on the oxidation of carbon nanostructures”. Since 2006 he is also employed as a consulting researcher and software architect by Kintech Lab Ltd, where he has a part time position till present time.
Ilya Valuev’s area of competence includes theoretical studies of nonideal (strongly coupled) plasmas, computer simulations of many-body quantum ensembles, DFT and tight binding simulations, parallel and distributed computing, Wave Packet Molecular Dynamics, electromagnetic simulations including finite-difference time domain method, architecture of computer simulation codes.
Ilya Valuev is an author and key developer of several computer simulation codes and libraries such as EMTL, GridMD, AWPMD. He received a number of grants and awards from the German Academic Exchange Service (DAAD), International Soros Science Education Program, the Russian Academy of Sciences, Russian Ministry of Science and Russian Foundation for Basic Research, etc.
Ilya Valuev is a co-author of 39 publications in peer-reviewed journals (WoS h-index is 13).