One-particle operator representation over two-particle basis sets for relativistic QED computations

19 May 2026, 17:59
1m
Aula (ÖAW)

Aula

ÖAW

Doktor-Ignaz-Seipel-Platz 2, 1010 Vienna

Speaker

Peter Hollosy (MTA–ELTE Lendület ‘Momentum’ Molecular Quantum electro-Dynamics Research Group, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter sétány 1/A, Budapest, H-1117, Hungary)

Description

This work is concerned with two(many)-spin-1/2-fermion relativistic quantum mechanics and it is about the construction of one-particle projectors and potentially, one-particle propagators, necessary for quantum-electrodynamics (QED) corrections, using an inherently two(many)-particle, `explicitly correlated' basis representation, necessary for good numerical convergence of the results.

It is demonstrated that a faithful representation of the one-particle operators, which appear in intermediate but essential computational steps, can be constructed over a many-particle basis set by accounting for the full Hilbert space, beyond the physically relevant anti-symmetric subspace.

Applications of this development can be foreseen
for the computation of quantum-electrodynamics corrections for a correlated relativistic reference state
and for high-precision relativistic computations of medium-to-high $Z$ helium-like systems, for which other two-particle projection techniques are unreliable.

References

[1] P. Hollósy, P. Jeszenszki, and E. Mátyus, J. Chem. Theory Comput. 20, 5122-5132 (2024). arXiv:2406.07086

Author

Peter Hollosy (MTA–ELTE Lendület ‘Momentum’ Molecular Quantum electro-Dynamics Research Group, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter sétány 1/A, Budapest, H-1117, Hungary)

Co-authors

Prof. Edit Matyus (ELTE, Eotvos Lorand University) Péter Jeszenszki (ELTE, Eötvös Loránd University)

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