Search results for " Quantum Mechanics."
showing 10 items of 197 documents
J-File Sum Rule Tests for the 3s-3p Transition Array in Singly Ionized Nitrogen - Comparison of Measured and Calculated Data
2005
1. IntroductionIn recent years quite a large number of transition probabilities of spectrallines of light elements have been determined including data for singly ionizednitrogen [1{7]. Some of these experimental as well as theoretical studies providealso data for a few triplet{singlet intersystem transitions, being very interestinge.g. from astrophysical point of view. The energy level system of NII has adistinguished feature compared to the neighboring two members of the carbonisoelectronic sequence (CI, OIII) | the energy difierence between the excitedterms 3
Quantum Spin-Tunneling:A Path Integral Approach
1995
We investigate the quantum tunneling of a large spin in a crystal field and an external magnetic field. The twofold degeneracy of the corresponding classical ground state is removed due to tunneling. The tunnel splitting ΔE o of the ground state is calculated by use of a path integral formalism. It is shown that coherent spin state path integrals do not yield a reasonable result. However a “bosonlzation” of the spin system yields excellent results in the semiclassical limit. This result follows from the coherent spin state approach from replacing the spin quantum number s by s + 1/2 which causes a renormalization of the preexponential factor of ΔE o .
Supersymmetric associated vector coherent states and generalized Landau levels arising from two-dimensional supersymmetry
2008
We describe a method for constructing vector coherent states for quantum supersymmetric partner Hamiltonians. The method is then applied to such partner Hamiltonians arising from a generalization of the fractional quantum Hall effect. Explicit examples are worked out.
Radiative lifetimes of the(1–3)Π1states in NaCs: Experiment and theory
2007
The radiative lifetimes of the $(3)\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Pi}$ and $D(2)\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Pi}$ states of the NaCs molecule have been directly measured in a thermal cell from fluorescence kinetics after modulated laser excitation. The experimental ${\ensuremath{\tau}}_{(3)\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Pi}}^{\mathrm{rad}}$ values of the $(3)\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Pi}({v}^{\ensuremath{'}}∊[3,25];{J}^{\ensuremath{'}}∊[25,106])$ levels decrease from $29\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}21\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$ as the ${v}^{\ensuremath{'}}$ values increase. The measured …
Coulomb sum rule for He4 and O16 from coupled-cluster theory
2020
We demonstrate the capability of coupled-cluster theory to compute the Coulomb sum rule for the $^{4}\mathrm{He}$ and $^{16}\mathrm{O}$ nuclei using interactions from chiral effective field theory. We perform several checks, including a few-body benchmark for $^{4}\mathrm{He}$. We provide an analysis of the center-of-mass contaminations, which we are able to safely remove. We then compare with other theoretical results and experimental data available in the literature, obtaining a fair agreement. This is a first and necessary step towards initiating a program for computing neutrino-nucleus interactions from first principles in coupled-cluster theory and supporting the experimental long-base…
Proton-neutron correlations and the longitudinal nuclear response
1988
We study the influence of the proton-neutron correlations, in particular of the tensor ones, on the longitudinal nuclear response. They generate a high-energy tail that we evaluate. We show that this tail produces an apparent quenching of the Coulomb sum rule. The amount of quenching found is significant, although insufficient to explain the totality of the missing strength.
Finite amplitude method applied to giant dipole resonance in heavy rare-earth nuclei
2015
Background: The quasiparticle random phase approximation (QRPA), within the framework of the nuclear density functional theory (DFT), has been a standard tool to access the collective excitations of the atomic nuclei. Recently, finite amplitude method (FAM) has been developed, in order to perform the QRPA calculations efficiently without any truncation on the two-quasiparticle model space. Purpose: We discuss the nuclear giant dipole resonance (GDR) in heavy rare-earth isotopes, for which the conventional matrix diagonalization of the QRPA is numerically demanding. A role of the Thomas-Reiche-Kuhn (TRK) sum rule enhancement factor, connected to the isovector effective mass, is also investig…
Hybrid optomechanics for Quantum Technologies
2014
We review the physics of hybrid optomechanical systems consisting of a mechanical oscillator interacting with both a radiation mode and an additional matter-like system. We concentrate on the cases embodied by either a single or a multi-atom system (a Bose-Einstein condensate, in particular) and discuss a wide range of physical effects, from passive mechanical cooling to the set-up of multipartite entanglement, from optomechanical non-locality to the achievement of non-classical states of a single mechanical mode. The reviewed material showcases the viability of hybridised cavity optomechanical systems as basic building blocks for quantum communication networks and quantum state-engineering…
THE ROLE OF CONCEPTUAL FOUNDATIONS OF QUANTUM THEORY IN THE DIALOGUE BETWEEN SCIENCE AND RELIGION
2001
A recent development in the understanding of conceptual foundations of quantum theory is discussed, giving particular attention to the analysis of the so called Schroedinger’s cat paradox. The solution of this problem in the frameworks of Everett-Wheeler many-worlds interpretation of quantum mechanics is considered, as well as the philosophical and theological consequences following from this interpretation. The recommendations are given, concerning the use of questions related with conceptual foundations of quantum theory in the education when introducing students and senior class pupils in problems of the dialogue between science and religion. KEY WORDS: science, religion, dialogue, found…
Heisenberg Uncertainty in Reduced Power Algebras
2011
The Heisenberg uncertainty relation is known to be obtainable by a purely mathematical argument. Based on that fact, here it is shown that the Heisenberg uncertainty relation remains valid when Quantum Mechanics is re formulated within far wider frameworks of {\it scalars}, namely, within one or the other of the infinitely many {\it reduced power algebras} which can replace the usual real numbers $\mathbb{R}$, or complex numbers $\mathbb{C}$. A major advantage of such a re-formulation is, among others, the disappearance of the well known and hard to deal with problem of the so called "infinities in Physics". The use of reduced power algebras also opens up a foundational question about the r…