Phaseless auxiliary-field quantum Monte Carlo method for cavity-QED matter systems
ORAL
Abstract
We present a generalization of the phaseless auxiliary-field quantum Monte Carlo (AFQMC) method to cavity
quantum-electrodynamical (QED) matter systems. The method can be formulated in both the Coulomb and
the dipole gauge. We verify its accuracy by benchmarking calculations on a set of small molecules against full
configuration interaction and state-of-the-art QED coupled cluster (QED-CCSD) calculations. Our results
show that (i) gauge invariance can be achieved within correlation-consistent Gaussian basis sets, (ii) the
accuracy of QED-CCSD can be enhanced significantly by adding the standard perturbative triples correction
without light-matter coupling, and (iii) there is a straightforward way to evaluate the differential expression
for the photon occupation number that works in any gauge. The high accuracy and favorable computational
scaling of our AFQMC approach will enable a broad range of applications. Besides polaritonic chemistry, the
method opens a way to simulate extended QED matter systems.
quantum-electrodynamical (QED) matter systems. The method can be formulated in both the Coulomb and
the dipole gauge. We verify its accuracy by benchmarking calculations on a set of small molecules against full
configuration interaction and state-of-the-art QED coupled cluster (QED-CCSD) calculations. Our results
show that (i) gauge invariance can be achieved within correlation-consistent Gaussian basis sets, (ii) the
accuracy of QED-CCSD can be enhanced significantly by adding the standard perturbative triples correction
without light-matter coupling, and (iii) there is a straightforward way to evaluate the differential expression
for the photon occupation number that works in any gauge. The high accuracy and favorable computational
scaling of our AFQMC approach will enable a broad range of applications. Besides polaritonic chemistry, the
method opens a way to simulate extended QED matter systems.
*L.W. acknowledges support by the Deutsche Forschungsgemeinschaft (DFG, GermanResearch Foundation) through grant WE 7176-1-1. The Flatiron Institute is a division of the Simons Foundation.
–
Presenters
-
Lukas Weber
- Simons Foundation (Flatiron Institute)