Accelerated path integrals through multiple time stepping
© 2016 EPFL
Simulating the quantum nature of light nuclei, such as hydrogen or lithium, without compromising on the description of the electronic structure of materials and molecules, can now be achieved by combining multiple time stepping techniques in real and imaginary time.
The paper "Accurate molecular dynamics and nuclear quantum effects at low cost by multiple steps in real and imaginary time: Using density functional theory to accelerate wavefunction methods" demonstrates how it is possible to model accurately the quantum nature of light nuclei, while using high levels of quantum theory in the description of the electrons.
The accurate (and computationally-demanding) part can be computed only once in a while, filling the gaps in the real-time trajectory as well as in the "imaginary-time" path integrals with a less expensive density-functional calculation. This method, that is fully compatible with other strategies to reduce the expense of modelling quantum nuclei, is available in a development version of the i-PI package.