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Reference : USR3441-MATHAE-007
Workplace : GIF SUR YVETTE
Date of publication : Thursday, January 10, 2019
Type of Contract : FTC Scientist
Contract Period : 18 months
Expected date of employment : 1 April 2019
Proportion of work : Full time
Remuneration : 2600 - 3600 € / month brutto depending on experience
Desired level of education : PhD
Experience required : 1 to 4 years
A postdoctoral position, funded by ECAM (https://www.e-cam2020.eu/about-us/), is available to work with Rodolphe Vuilleumier at the ENS-Paris and David Lauvergnat at the University Paris-sud (Orsay). The successful candidate will explore new efficient and accurate quantum dynamical methods using the combination of two complementary computational methods, path integral and Smolyak scheme approaches to study floppy systems (such as H2 clathrate hydrates). In particular and related to the software development infrastructure, ECAM, the HPC aspect is one the key point of this project.
The position will start as early as possible and up to two years. However, the funding will stop at the end of September 2020. The hired postdoc will be located at the “Maison de la Simulation” in the south of Paris.
In this project, we will explore new efficient and accurate quantum dynamical methods to study from first principles the behavior of floppy systems exhibiting delocalized quantum states coupled to an environment. Such a situation occurs for example in the case of a molecule encapsulated in a nanoscale cavity, a situation that occurs in clathrate hydrates. A first application will then be H2 clathrates, which are intensively studied, experimentally and theoretically.
The goal of this project is to combine two complementary computational methods: (i) The Smolyak scheme was recently introduced in quantum dynamics by Carrington et al. It uses a wavefunction description but enables to overcome the exponential scaling by substituted the huge direct-product grid by a sum of small direct-product grids. This new technic is currently implemented in the quantum dynamics code, ElVibRot, developed in Orsay. Furthermore, it has been shown recently, that a parallelization using OpenMP gives good speed-up. One important aspect of this proposal is to port the current implementation with an MPI parallelism on a multi-node architecture and if possible with a multi-layer parallelism (MPI/OpenMP or GPU) strategy. (ii) The Path Integral Method is based on the representation of the system in term of Feynman's path integrals, each classical point particle being replaced by a necklace of beads. The method is exact for the description of thermal properties at equilibrium. Using linearization, an extension to dynamical properties has been recently proposed and implemented in the PaPIM code. However, the description of delocalized states such as low energy rotational degrees of freedom turns out to be difficult in this framework due to the large number of beads needed. The current proposal aims at combining the two approaches with some degrees of freedom described by the Smolyak sparse grid approach, while others, the bath are described using path integrals.
The hired postdoc should have prior knowledge on the development of Fortran codes for HPC (opemmp/MPI) and at least one quantum simulation method for molecular systems: quantum dynamics and Path-Integral approach.
The hired postdoc will be located at the “Maison de la Simulation” and he/she will benefit from the expertise on parallelism locally at the “Maison de la Simulation”, ENS and also from the ECAM program and on quantum dynamics and Path-Integral approach at the University Paris-sud (Orsay) with David Lauvergnat and at the ENS-Paris with Rodolphe Vuilleumier.
E-CAM (European HPC Center of Excellence) est une e-infrastructure pour la formation et le développement de logiciels en simulation et modélisation en relation avec l'industrie (https://www.e-cam2020.eu/about-us/). Les aspects de HPC sont particulièrement important pour ce projet et quatre domaines d'intérêt scientifique en informatique sont considérés, dont la "dynamique quantique" (https://www.e-cam2020.eu/quantum-dynamics/).
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