2018/07/31 by Nicholas Funai, Jorma Louko, Eduardo Martín-Martínez +1
Computer Science · Physics and Astronomy · #Coupling (piping) #Dipole #Discrete dipole approximation #Gauge (firearms) #Mechanical and Optical Resonators #Physics #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum mechanics #Theoretical physics #hep-th #quant-ph
paper · pdf · doi:10.1103/physrevd.99.065014
published as Phys. Rev. D 99, 065014 (2019) · 19 pages: 11 pages + 8 pages of appendices. 7 figures. RevTeX 4.1
openalex created_date 2018/08/03 · openalex publication_date 2019/03/26 · arxiv created 2019/05/06 · arxiv updated 2019/05/08 · openalex updated_date 2026/08/05
We compare the predictions of the fundamentally motivated minimal coupling (\stackrel^\mathbitp\ifmmode⋅\else\textperiodcentered\fi\stackrel^\mathbitA) and the ubiquitous dipole coupling (\stackrel^\mathbitx\ifmmode⋅\else\textperiodcentered\fi\stackrel^\mathbitE) in the light-matter interaction. By studying the light-matter interaction for hydrogenlike atoms we find that the dipole approximation cannot be a priori justified to analyze the physics of vacuum excitations (a very important phenomenon in relativistic quantum information) since a dominant wavelength is absent in those problems, no matter how small (as compared to any frequency scale) the atom is. Remarkably, we show that the dipole approximation in those regimes can still be valid as long as the interaction time is longer than the light-crossing time of the atoms, which is a very reasonable assumption. We also highlight some of the subtleties that one has to be careful with when working with the explicitly gauge noninvariant nature of the minimal coupling, and we compare it with the explicitly gauge invariant dipole coupling.