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Elementary Particles and Interactions — Overview
Published in K Grotz, H V Klapdor, S S Wilson, The Weak Interaction in Nuclear, Particle and Astrophysics, 2020
K Grotz, H V Klapdor, S S Wilson
The quantum field theory of the electromagnetic interaction, quantum electrodynamics (QED), is by far the best studied and tested quantum field theory. Its predictions are in excellent agreement with experimental data. Two examples of very thoroughly investigated quantum field effects are the Lamb shift and the deviation of the electromagnetic g factor from the value two. The value predicted in eighth order QED (Kinoshita (1981)): () g−22=1159652460(±127)(±75)⋅10−12
Nuclear and Particle Physics
Published in Walter Fox Smith, Experimental Physics, 2020
Just as there was a time, centuries ago, that electric and magnetic phenomena were considered distinct, electromagnetic and weak forces are typically listed separately. Electric and magnetic phenomena were unified under Maxwell’s theory of classical electromagnetism in the 19th century, and more recently under the quantum field theory called quantum electrodynamics (or “QED”). QED remains the archetype of a quantum field theory. After its development, a quantum field theory with a unified explanation for both electromagnetic and weak phenomena was developed, called “electroweak” theory. Considered from this perspective, the separate electromagnetic and weak forces have been combined under a single electroweak description.
Quantization of Maxwell’s Equations and Electromagnetic Field
Published in Maged Marghany, Automatic Detection Algorithms of Oil Spill in Radar Images, 2019
It is incorrect to isolate the quantum field theory from the electromagnetic wave theories. Indeed, both fields are compiled to present the field of quantum electrodynamics. In this sense, quantum electrodynamics, which refers to a quantum field theory of the electromagnetic force. The electromagnetic field is a keystone to comprehend the remote sensing technology. The main theory of remote sensing; therefore, is based on the photoelectric effect. In other words, the concept of energy in a photon is very important for remote sensing technology. Indeed, the photoelectric effect was the first example of a quantum phenomenon to be seen at the end of the 19th century [21]. In this understanding, photons played a key part in the quantum theory of the electromagnetic field, which is known as quantum electrodynamics—not only serving as the particles of electromagnetic radiation; but also as the carrier of the electromagnetic force. Any electromagnetic phenomenon; for instance, the attraction between two opposite electric charges or dual magnets repelling one another, is understood through the vital exchange of the photon particles.
Pair and mediated RET between two chiral molecules
Published in Molecular Physics, 2022
A fundamental understanding of these types of light–matter and inter-particle interactions has been afforded by molecular quantum electrodynamics (QED) theory [16–18]. Its defining feature is that both the electromagnetic field and the atoms and molecules are treated quantum mechanically, furnishing a description in which photons are emitted or absorbed in spectroscopic processes or exchanged in coupling between particles [19,20]. Because of the inherent symmetry constraints associated with chiral compounds, spectroscopic selection rules for chiroptical phenomena involving such species are less stringent than usual, permitting higher multipole moment transitions to occur. It is often sufficient, however, to remain within the dipolar approximation for the interaction of light with chiral moieties by retaining the electric dipole coupling term but extending it to include the interaction of the magnetic dipole moment with the magnetic field. No special accommodations need to be made within the framework of molecular QED theory to account for magnetic phenomena since both the charge and current density distributions are included from the very beginning of its construction. Propitiously, this leads to the description of molecular handedness in terms of a time-even parity-odd pseudoscalar formed from the product of transition electric and magnetic dipole moments of the chiral object, a quantity that appears explicitly in quantum mechanical observables of numerous molecular chiroptical effects.
Locally acting mirror Hamiltonians
Published in Journal of Modern Optics, 2021
Jake Southall, Daniel Hodgson, Robert Purdy, Almut Beige
In classical electrodynamics, we often characterize light by its local properties such as local amplitudes, direction of propagation and polarization. Its fundamental equations of motion – Maxwell's equations – are local differential equations. Practically, we assume that the classical electromagnetic (EM) field comprises a continuum of local field excitations. In contrast to this, quantum electrodynamics routinely decomposes the EM field into monochromatic waves, which are highly non-local. Such a non-local approach can result in more complicated equations of motion than strictly necessary. For example, the Green's functions of macroscopic quantum electrodynamics correlate an observer's position with all spatial positions and photon frequencies [1–3]. Therefore, in this paper, we take an alternative approach and quantize the EM field in position space. As in classical electrodynamics, our equations of motion only depend on local properties. Hence we expect them to find many applications, for example, in modelling systems involving local light-matter interactions or featuring ultrabroadband photonic wave packets [4–7].
Photon blockade through microcavity-engineered plasmonic resonances
Published in Journal of Modern Optics, 2019
Yue Yu, Hong-Yu Liu, Rong-Can Yang
In summary, we have reviewed and considered the UPB of the MNP-cavity system with laser- driven cavity and MNP. With the analytical method, it is clear that the optimal parameters for strong photon antibunching are dependent on the coupling strength between the MNP and cavity. The system exhibits a strong antibunching effect on weak MNP-cavity interaction strength J, and the photon blocking effect is only produced in the weak coupling . The scheme can be achieved in the current experimental techniques easily, for controlling the statistical properties of the photons by tuning the coupling strength between the cavity modes and MNP. Therefore, our results may be significant and important in generating tunable single-photon sources and could be very helpful for cavity quantum electrodynamics systems.