ATOMIC VELOCITY SELECTION BY INTERFERENCE IN TWO-PHOTON IONIZATION

1996 ◽  
Vol 05 (04) ◽  
pp. 911-919
Author(s):  
J.C. GARREAU ◽  
D. WILKOWSKI ◽  
D. HENNEQUIN ◽  
V. ZEHNLÉ
Keyword(s):  
Electromagnetic Field ◽  
Quantum Interference ◽  
Quantum Coherence ◽  
Degrees Of Freedom ◽  
Internal State ◽  
Center Of Mass ◽  
Mass Motion ◽  
Two Photon ◽  
Selective Ionization ◽  
Velocity Selection

This paper discusses a new scheme for generating quantum coherence between different degrees of freedom of an atom interacting with two modes of the electromagnetic field. The presence of quantum interference in a two-photon coupling between the ground state of the atom and the continuum through two quasi-resonant intermediate states induces selective ionization of the atoms for particular combinations of the different parameters characterizing the degrees of freedom of the system, leading to quantum coherence between the internal state, the center-of-mass motion of the atom, and the electromagnetic field. The application of this method to the selection of an atomic velocity class is discussed.

DISCUSSION OF THE CENTER OF MASS MOTION IN A SYSTEM WITH THREE DEGREES OF FREEDOM

2013 ◽  
Vol 22 (06) ◽  
pp. 1350043
Author(s):  
WERNER SCHEID
Keyword(s):  
Degrees Of Freedom ◽  
Center Of Mass ◽  
Hermite Polynomials ◽  
Wave Functions ◽  
Basis Set ◽  
Mass Motion ◽  
Laboratory System ◽  
Oscillator Potential ◽  
Harmonic Oscillator Potential ◽  
Three Degrees Of Freedom

This paper considers the problem of the center of mass motion of three fermionic particles, e. g., equal nucleons (no spin), which can move only in the x-direction in the laboratory system. This system (with three degrees of freedom only) is transformed to a system where one coordinate is proportional to the center of mass coordinate. The center of mass moves in a harmonic oscillator potential. The basis set of wave functions is constructed with Hermite polynomials in part. As example we study the case of a quadratic intrinsic potential between the particles. The problem may be important for the motion of three nucleons in a crystal channel.

Zur Beschreibung relativistischer Teilchen höheren Spins im elektromagnetischen Feld / The Description of Relativistic Particles with Arbitrary Spin in the Electromagnetic Field,

1972 ◽  
Vol 27 (2) ◽  
pp. 339-362
Author(s):  
Wolfgang Ulrici
Keyword(s):  
Electromagnetic Field ◽  
Wave Equation ◽  
Center Of Mass ◽  
Arbitrary Spin ◽  
Canonical Representation ◽  
Mass Motion ◽  
Homogeneous Electromagnetic Field ◽  
Spinor Representations ◽  
Special Case ◽  
Relativistic Particles

AbstractStarting with the equations of the center-of-mass motion and spin motion of a particle in a homogeneous electromagnetic field, we derive the Hamiltonian and the wave equation of a relativistic particle with arbitrary spin and arbitrary magnetic moment in this field. We change from the canonical representation to spinor representations with convenient transformation properties, and we find a form of the wave equation which, for the special case of spin 1/2, coincides with the Dirac equation (in the form first given by Feynman). The problems and limitations of this derivation are extensively discussed.

Mechanically-Tunable Quantum Interference in Ferrocene-Based Single-Molecule Junctions

2020 ◽  
Author(s):  
María Camarasa-Gómez ◽  
Daniel Hernangómez-Pérez ◽  
Michael S. Inkpen ◽  
Giacomo Lovat ◽  
E-Dean Fung ◽  
...  
Keyword(s):  
Single Molecule ◽  
Quantum Interference ◽  
Degrees Of Freedom ◽  
Building Blocks ◽  
Ferrocene Derivative ◽  
Single Molecule Junctions ◽  
Molecule Junction ◽  
Single Molecule Junction ◽  
The Impact ◽  
D Orbitals

Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted<br>some interest as functional elements of molecular-scale devices. Here we investigate the impact of<br>the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction<br>conductance. Measurements indicate that the conductance of the ferrocene derivative, which is<br>suppressed by two orders of magnitude as compared to a fully conjugated analog, can be modulated<br>by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects that arise from the hybridization of metal-based d-orbitals and the ligand-based π-system. By rotating the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.<br>

NUCLEON IN NUCLEAR MEDIUM

2009 ◽  
Vol 18 (05n06) ◽  
pp. 1166-1175
Author(s):  
SHASHIKANT C. PHATAK
Keyword(s):  
Standard Procedure ◽  
Center Of Mass ◽  
Critical Density ◽  
Magnetic Interaction ◽  
Nuclear Medium ◽  
Mass Motion ◽  
Field Equations ◽  
Dielectric Model ◽  
Chiral Color Dielectric Model

The behavior of a nucleon in nuclear medium is discussed in Chiral Color Dielectric Model. It is assumed that the nucleons in nuclear medium produces a background dielectric field and the quark and dielectric field equations are solved self consistantly in presence of the dielectric field. A nucleon in nuclear medium is then constructed by means of standard procedure followed in chiral bag models. The corrections due to center of mass motion, color magnetic interaction and meson interaction are included. The calculations show that the nucleon becomes bigger in the medium but its mass does not change much. It is found that beyond a certian density, bound solutions in which quarks are bound in self-generated dielectric field are not possible. Thus, the calculations indicate that there is a critical density beyond which the matter consists of deconfined quarks.

scholarly journals The Use of Integrals in Numerical Integrations of theN-Body Problem

1971 ◽  
Vol 10 ◽  
pp. 40-51
Author(s):  
Paul E. Nacozy
Keyword(s):  
Angular Momentum ◽  
Numerical Integration ◽  
Degrees Of Freedom ◽  
Body Problem ◽  
Center Of Mass ◽  
Integration Step ◽  
Gravitational System ◽  
Systems Of Differential Equations ◽  
Numerical Integrations ◽  
Original Number

AbstractThe numerical integration of systems of differential equations that possess integrals is often approached by using the integrals to reduce the number of degrees of freedom or by using the integrals as a partial check on the resulting solution, retaining the original number of degrees of freedom.Another use of the integrals is presented here. If the integrals have not been used to reduce the system, the solution of a numerical integration may be constrained to remain on the integral surfaces by a method that applies corrections to the solution at each integration step. The corrections are determined by using linearized forms of the integrals in a least-squares procedure.The results of an application of the method to numerical integrations of a gravitational system of 25-bodies are given. It is shown that by using the method to satisfy exactly the integrals of energy, angular momentum, and center of mass, a solution is obtained that is more accurate while using less time of calculation than if the integrals are not satisfied exactly. The relative accuracy is ascertained by forward and backward integrations of both the corrected and uncorrected solutions and by comparison with more accurate integrations using reduced step-sizes.

Spontaneous emission in a standing-wave cavity: Classical center-of-mass motion

1992 ◽  
Vol 46 (11) ◽  
pp. 7162-7178 ◽  
Author(s):  
W. Ren ◽  
J. D. Cresser ◽  
H. J. Carmichael
Keyword(s):  
Standing Wave ◽  
Spontaneous Emission ◽  
Center Of Mass ◽  
Mass Motion
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