Atomic Quantum Electrodynamics Research Articles

Energy spectra of muonic atoms in quantum electrodynamics

Vacuum polarization, nuclear structure and recoil, radiative corrections to the hyperfine structure of S-states in muonic ions of lithium, beryllium and boron are calculated on the basis of quasipotential method in quantum electrodynamics. We consider contributions in first and second orders of perturbation theory which have the order α5 and α6 in the energy spectrum. Total values of hyperfine splittings are obtained which can be used for a comparison with future experimental data.

Photon Is Shortened Name for Electromagnetic Field but Not a Particle

We well know that photon concept is self-contradictory because we assume that it is a particle with wave properties. This contradiction insensibly spoils our subconscious thinking. It is shown in the article that photon has no 4-coordinates for work within atomic quantum electrodynamics (QED). This implies that actually photon is not a particle. I draw attention that QED is the most precise theory developed by humankind. It is noticed that terms photon and electromagnetic field in practice are in use as synonyms. These results validate the title of the article and exempt us from contradictions within quantum mechanics.

Detailed description of spontaneous emission

The wave side of wave–photon duality, describing light as an electromagnetic field (EMF), is used in this article. The EMF of spontaneous light emission (SE) of a laser-excited atom is calculated from first principles for the first time. This calculation is done using the simple method of atomic quantum electrodynamics. The EMF of SE is also calculated for three types of polyatomic light sources excited by a laser. It is shown that light radiated by such sources can be coherent, which explains recent experiments on SE of laser-excited atoms. Small sources of SE can be superradiant, which also conforms to experiment. Thus, SE is shown not to be a random event itself. Random properties of natural light are simply explained as a result of thermal excitation randomness without additional hypotheses. The EMF of SE is described by simple complex functions, but not real ones.

Realization of superposition and entanglement of coherent and squeezed states in circuit quantum electrodynamics

We propose a new scheme for generating the superposition and entanglement of the coherent states and squeezed states by considering N superconducting charge qubits (or artificial two-level atoms) interacting with photons in a high finesse cavity on a chip, assisted by a strong driving field. By virtue of the parameters of this system, we can generate novel quantum states, for example, multiparty entangled states and Schrodinger cat states among the superconducting qubits, coherent states and squeezed states of the cavity. These states, whose amplitudes are about two orders greater than those from the atomic quantum electrodynamics in classical cavity, are important for understanding the boundary between quantum and classical behavior and can be utilized in experimental studies on decoherence. This device may be an architecture for future solid-state quantum computation and communication.

Simple implementation of discrete quantum Fourier transform via cavity quantum electrodynamics

We propose a scheme for implementing discrete quantum Fourier transform in cavity quantum electrodynamics (QED). The experimental implementation is appealingly simple because the combined effect of the complex controlled-Rk gate and SWAP gate operations required for implementing discrete quantum Fourier transform in the naive quantum circuit is replaced by the one-step CRkS gate, which can be directly implemented via atom–cavity interaction with the assistance of classical fields. We propose the detailed experimental procedure and analyze the experimental feasibility. The experimental implementation of the scheme would show the full power of quantum algorithm and would open wide prospects for more complicated quantum computation with atoms in QED.

Energy-dependent many-body perturbation theory for few-electron systems: Pair functions with a virtual photon for helium-like systems

Analytical methods for atomic quantum electrodynamics (QED) calculations are mainly applicable to light elements, while available numerical methods work only for medium-heavy and heavy elements. A new numerical perturbative technique for energy-dependent interactions is being developed, based upon the recently introduced covariant evolution-operator method (Lindgren et al. Phys. Rep. 389, 181 (2004)). This could be used for combined many-body-QED calculations on light as well as heavy elements. The method is presently being implemented, and some preliminary numerical results for light helium-like ions are given.PACS Nos.: 31.30.Jv, 31.15.Md, 31.25.Jf, 33.15.Pw