Spontaneous decay in cold dense atomic systems: caloric effect and spectrum of emitted light

2016 ◽  
Vol 94 (7) ◽  
pp. 1-12
Author(s):  
Oleg Prepelita
Keyword(s):  
Critical Temperature ◽  
Spontaneous Emission ◽  
Cold Atoms ◽  
Atomic System ◽  
Transition Frequency ◽  
Atomic Transition ◽  
Spontaneous Decay ◽  
Atomic Systems ◽  
Caloric Effect ◽  
Atomic Transition Frequency

We discuss collision-induced spontaneous decay in a system of cold atoms and caloric effect manifesting in the heating of the atomic system during spontaneous decay. It is shown that the caloric effect is caused by inelastic atom–atom collisions accompanied by the spontaneous emission of photons. Because of the imbalance between the rate of emission of the photons with the frequency higher and lower than the atomic transition frequency, the atomic system, under some conditions, is heated up. The value of the critical temperature is found, which separates the regions where the collision-induced spontaneous decay is exothermic and endothermic.

Coherent energy transfer of a pair of two-level atoms

2019 ◽  
Vol 33 (24) ◽  
pp. 1950281
Author(s):  
Xiaogang Bai ◽  
Haiming Zhang
Keyword(s):  
Energy Transfer ◽  
Order Approximation ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Energy Transfer Efficiency ◽  
Transition Frequency ◽  
Atomic Transition ◽  
Transfer Efficiency ◽  
Coherent Resonance ◽  
Atomic Transition Frequency

The coherent energy transfer efficiency of a pair of two-level atoms is studied theoretically and its mathematical expression has been deduced. The problem of atoms coherent energy transfer theory is treated by quantum perturbation theory and equivalent method replacing atomic dipole field with light field of the same frequency. The detuning between the donor atom transition frequency and the acceptor atom transition frequency has been studied in the theory. With the increase of the detuning of the two-atomic transition frequency, the energy transfer efficiency decays rapidly. In the case of two-atomic transition frequency resonance, the coherent resonance energy transfer efficiency is directly proportional to the square of the sine of the minus three power of the distance between two atoms and the energy transfer efficiency is periodically decaying over time. The coherent resonance energy transfer efficiency is inversely proportional to the six power of the distance between the two atoms in the first-order approximation.

Criterion of Mechanical Instability in Inhomogeneous Atomic System

2005 ◽  
Vol 482 ◽  
pp. 127-130 ◽  
Author(s):  
Yoshitaka Umeno ◽  
Takayuki Kitamura
Keyword(s):  
Mechanical Stability ◽  
Atomic System ◽  
Instability Criterion ◽  
Fundamental Issue ◽  
Mechanical Instability ◽  
Atomic Systems ◽  
Uniform Deformation ◽  
Atomic Structures ◽  
Homogeneous Structures ◽  
Deformation Modes

The mechanical stability of a material is a fundamental issue in strength of atomic systems. Although the criterion of the mechanical stability of homogeneous structures such as perfect crystals have been successfully investigated so far, the criterion has not been able to be precisely evaluated in the cases of non-uniform deformations or bodies of inhomogeneous atomic structures. Now we present an instability criterion of an arbitrary atomic structure based on the energy balance of the whole system. This method gives the mathematically rigorous condition for the onset of an unstable deformation in any inhomogeneous atomic system. Furthermore, the method can be applied to any type of potential field, which means that ab initio evaluations of the mechanical instability of inhomogeneous structure under non-uniform deformation will be possible. The validity of the method is clarified by the application to tension of a cracked body. The onsets of unstable deformations and their deformation modes are precisely evaluated by the method.

scholarly journals Frames for operators in Banach spaces via semi-inner products

2016 ◽  
Vol 14 (03) ◽  
pp. 1650011 ◽  
Author(s):  
Bahram Dastourian ◽  
Mohammad Janfada
Keyword(s):  
Banach Space ◽  
Banach Spaces ◽  
Reproducing Kernel ◽  
Atomic System ◽  
Inner Product ◽  
Reconstruction Formula ◽  
Frame Operator ◽  
Atomic Systems ◽  
Perturbation Result ◽  
Reproducing Kernel Banach Spaces

In this paper, the concept of a family of local atoms in a Banach space is introduced by using a semi-inner product (s.i.p.). Then this concept is generalized to an atomic system for operators in Banach spaces. We also give some characterizations of atomic systems leading to new frames for operators. In addition, a reconstruction formula is obtained. The characterizations of atomic systems allow us to state some results for sampling theory in s.i.p reproducing kernel Banach spaces. Finally, we define the concept of frame operator for these kinds of frames in Banach spaces and then we establish a perturbation result in this framework.

KINETICS OF THE SPONTANEOUS DECAY IN COLD ATOMIC SYSTEMS

2020 ◽  
Author(s):  
Oleg Prepelita
Keyword(s):  
Emission Spectrum ◽  
Initial Temperature ◽  
Dipole Interaction ◽  
Time Profile ◽  
Spontaneous Decay ◽  
Spontaneous Transition ◽  
Atomic Systems ◽  
Leading Role ◽  
Kinetics Of ◽  
Strong Dipole

We discuss the spontaneous decay in a system of cold identical two-level atoms when, due to the strong dipole-dipole interaction, the collision-induced spontaneous decay plays the leading role in the process. We show that the time profile of the spontaneous transition is essentially non-exponential. Also, we argue that at a low initial temperature of the atomic system the spontaneous decay is accompanied by a strong heating caused by the inelastic atom-atom collisions. We show that the spontaneous emission spectrum is asymmetric. In addition, the width of the emission spectrum is a function of time. While atoms decay the emission spectrum becomes broader. The spectrum’s asymmetry and the atomic system’s heating have the same physical origin coming from the peculiarities of the atoms distribution function.

scholarly journals OPTIMIZED QUASIPARTICLE DENSITY FUNCTIONAL APPROACH FOR MULTIELECTRON ATOMIC SYSTEMS

2021 ◽  
pp. 38-44
Author(s):  
A. Glushkov ◽  
V. Kovalchuk ◽  
A. Sofronkov ◽  
A. Svinarenko
Keyword(s):  
Density Functional ◽  
Atomic System ◽  
Mass Operator ◽  
Fermi Liquids ◽  
Dft Theory ◽  
Functional Theory ◽  
Atomic Systems ◽  
Hartree Fock ◽  
The Third ◽  
Quasiparticle Density

We present the optimized version of the quasiparticle density functional theory (DFT), constructed on the principles of the Landau-Migdal Fermi-liquids theory and principles of the optimized one-quasiparticle representation in theory of multielectron systems. The master equations can be naturally obtained on the basis of variational principle, starting  from a Lagrangian of an atomic system as a functional of  three quasiparticle densities. These densities  are similar to the Hartree-Fock (HF)  electron density and kinetical energy density correspondingly, however the third density  has no an analog in the Hartree-Fock or the standard  DFT theory and appears as result of account for the energy dependence of the mass operator S. The elaborated  approach to construction of the eigen-functions basis can be characterized as an improved one in comparison with similar basises of other one-particle representations, namely, in the HF,  the standard Kohn-Sham approximations etc.

scholarly journals Two-body corrections to the g factors of the bound muon and nucleus in light muonic atoms

2019 ◽  
Vol 73 (10) ◽  
Author(s):  
Savely G. Karshenboim ◽  
Vladimir G. Ivanov
Keyword(s):  
Electrostatic Interaction ◽  
Coulomb Potential ◽  
Atomic System ◽  
Magnetic Moments ◽  
Master Equations ◽  
Atomic Systems ◽  
Muonic Atoms ◽  
Pure Coulomb ◽  
Coulomb Effects ◽  
Three Body

Abstract A nonrelativistic (NR) theory of recoil corrections to the magnetic moments of bound particles is revisited. A number of contributions can be described within an NR theory with the help of various potentials. We study those potential-type contributions for two-body atomic systems. We have developed an approach, that allows us to find the g factor for an electron or muon in a two-body bound system for an arbitrary electrostatic interaction together with the m/M recoil corrections, as well as the binding corrections to the g factor of the nucleus. We focus our attention on light muonic two-body atoms, where the recoil effects are enhanced. Both mentioned kinds of contributions have been previously known only for the pure Coulomb effects. We have applied the here-obtained master equations to a few particular cases of perturbations of the Coulomb potential. In particular, the results on the recoil corrections to the finite-nuclear-size (FNS) and Uehling-potential contributions to the g factor of the bound muon are obtained. The Uehling-potential and FNS contributions to the g factor of the bound nucleus have been found as well together with the related recoil corrections. We have generalized the results for the case of the g factor of a bound muon in a three-body atomic system consisting of an electron, a muon, and a spinless nucleus. Graphical abstract

Atom Optomechanics

2020 ◽  
pp. 329-368
Author(s):  
Philipp Treutlein
Keyword(s):  
Ultracold Atoms ◽  
Quantum Control ◽  
Cold Atoms ◽  
Internal State ◽  
Trapped Atoms ◽  
Sympathetic Cooling ◽  
Atomic Systems ◽  
Mechanical Oscillators ◽  
Optomechanical Coupling ◽  
Coupling Mechanisms

This chapter gives an introduction to optomechanics with ultracold atoms. The opening half deals with optomechanical atom–light interactions. Section 9.2 introduces atom trapping. Section 9.3 discusses the properties of trapped atoms as mechanical oscillators. Section 9.4 describes optomechanical interactions, treating the atoms as polarizable particles, a model used in section 9.5 to derive optomechanical coupling of atoms and a cavity field and briefly review cavity optomechanics experiments with atoms in the quantum regime. The second half deals with hybrid mechanical-atomic systems. We start with an overview of different coupling mechanisms, then focus on light-mediated interactions and derive the coupling of a membrane to an ensemble of laser-cooled atoms. Section 9.8 reviews experiments on sympathetic cooling of a membrane with cold atoms, with perspectives for mechanical quantum control discussed in section 9.9. Section 9.10 introduces the possibilities that arise if the mechanical oscillator is coupled to the atomic internal state.

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