Multielectronic Atom in Magnetic Field Revisited

Electronic Structure of Superheavy Atoms. Revisited

The electronic structure of an atom with Z <= 137 can be described by the Dirac equation with the Coulomb field of a point charge Ze. It was believed that the Dirac equation with Z > 137 is inconsistent and physically meaningless because the formula for the lower energy level of the Dirac Hamiltonian formally gives imaginary eigenvalues. But a strict mathematical consideration shows that difficulties with the electronic spectrum for Z > 137 do not arise if the Dirac Hamiltonian is correctly defined as a self-adjoint operator, see [1]. In this article, we brie y summarize the main physical resu…

The one dimensional Hydrogen atom revisited

The one dimensional Schroedinger hydrogen atom is an interesting mathematical and physical problem to study bound states, eigenfunctions and quantum degeneracy issues. This 1D physical system gave rise to some intriguing controversy over more than four decades. Presently, still no definite consensus seems to have been reached. We reanalyzed this apparently controversial problem, approaching it from a Fourier transform representation method combined with some fundamental (basic) ideas found in self-adjoint extensions of symmetric operators. In disagreement with some previous claims, we found th…

再探 Duan-Kimble 腔–原子量子存储器加载方案

The Duan-Kimble cavity-atom quantum memory loading scheme revisited

本文纠正 Duan-Kimble 方案中单光子反射率函数的误用，并提出将光子与腔调谐至原子共振中点的 push-pull 构型，以更高保真度和预示概率改进量子存储器加载。

The two-dimensional hydrogen atom revisited

The bound state energy eigenvalues for the two-dimensional Kepler problem are found to be degenerate. This "accidental" degeneracy is due to the existence of a two-dimensional analogue of the quantum-mechanical Runge-Lenz vector. Reformulating the problem in momentum space leads to an integral form of the Schroedinger equation. This equation is solved by projecting the two-dimensional momentum space onto the surface of a three-dimensional sphere. The eigenfunctions are then expanded in terms of spherical harmonics, and this leads to an integral relation in terms of special functions which has …

Unruh Acceleration Radiation Revisited

When ground-state atoms are accelerated and the field with which they interact is in its normal vacuum state, the atoms detect Unruh radiation. We show that atoms falling into a black hole emit acceleration radiation which, under appropriate initial conditions (Boulware vacuum), has an energy spectrum which looks much like Hawking radiation. This analysis also provides insight into the Einstein principle of equivalence between acceleration and gravity. The Unruh temperature can also be obtained by using the Kubo--Martin--Schwinger (KMS) periodicity of the two-point thermal correlation function…

再访缀饰原子：辐射级联的独立于哈密顿量处理

Dressed atom revisited: Hamiltonian-independent treatment of the radiative cascade

本文提出独立于具体哈密顿量的缀饰原子框架，分析辐射级联与缀饰态参数的关系，给出谱线发射性质判据，并用于永久偶极矩导致的低能发射。

The He atom revisited

In the Feynman-Kac[1] path integral approach the eigenvalues of a quantum system can be computed using Wiener measure which uses Brownian particle motion. In our previous work[2-3] on such systems we have observed that the Wiener process numerically converges slowly for dimensions greater than two because almost all trajectories will escape to infinity[4]. One can speed up this process by using a Generalized Feynman-Kac (GFK) method[5] in which the new measure associated with the trial function is stationary, so that the convergence rate becomes much faster. We thus achieve an example of Impor…

Quantum resonant effects in the delta-kicked rotor revisited

We review the theoretical model and experimental realization of the atom optics $δ-$kicked rotor (AOKR), a paradigm of classical and quantum chaos. We have performed a number of experiments with an all-optical Bose-Einstein condensate (BEC) in a periodic standing wave potential in an AOKR system. We discuss results of the investigation of the phenomena of quantum resonances in the AOKR. An interesting feature of the momentum distribution of the atoms obtained as a result of short pulses of light, is the variance of the momentum distribution or the kinetic energy $<p^{2}>/2m$ in units of the re…

N Level System with RWA and Analytical Solutions Revisited

In this paper we consider a model of an atom with n energy levels interacting with n(n-1)/2 external (laser) fields which is a natural extension of two level system, and assume the rotating wave approximation (RWA) from the beginning. We revisit some construction of analytical solutions (which correspond to Rabi oscillations) of the model in the general case and examine it in detail in the case of three level system.

偶极近似下的自发辐射——再考察

Spontaneous emission in dipole approximation -- revisited

本文结合源场理论与薛定谔绘景重新分析偶极近似自发辐射，检验不作 RWA/WWA 时的能量场量，并指出全频率微扰求和导致非物理布居。

Positive-energy spectra of atomic hydrogen in a magnetic field with an adiabatic-basis-expansion method

The problem of photoionization of atomic hydrogen in a white-dwarf-strength magnetic field is revisited to understand the existing discrepancies in the positive-energy spectra obtained by a variety of theoretical approaches reported in the literature. Oscillator strengths for photoionization are calculated with the adiabatic-basis-expansion method developed by Mota-Furtado and O'Mahony [Phys. Rev. A {\bf 76}, 053405 (2007)]. A comparative study is performed between the adiabatic-basis-expansion method and our previously developed coupled-channel theory [Phys. Rev. A {\bf 94}, 033422 (2016)]. A…