Search results for " Levels"
showing 10 items of 483 documents
Measurement of the 2+→0+ ground-state transition in the β decay of F20
2019
We report the first detection of the second-forbidden, nonunique, 2+→0+, ground-state transition in the β decay of F20. A low-energy, mass-separated F+20 beam produced at the IGISOL facility in Jyvaskyla, Finland, was implanted in a thin carbon foil and the β spectrum measured using a magnetic transporter and a plastic-scintillator detector. The β-decay branching ratio inferred from the measurement is bβ=[0.41±0.08(stat)±0.07(sys)]×10-5 corresponding to logft=10.89(11), making this one of the strongest second-forbidden, nonunique β transitions ever measured. The experimental result is supported by shell-model calculations and has significant implications for the final evolution of stars tha…
Orientation of O(3) and SU(2)⊗CI representations in cubic point groups (Oh,Td) for application to molecular spectroscopy
2003
Abstract We propose a detailed method for the symmetrization of the standard O (3) or SU (2)⊗ C I basis | j τ , m 〉 ( τ = g or u ) into the O h or T d point group. This is realized by means of an orientation matrix called G . The oriented basis obtained in this way allows matrix element calculations for rovibronic spectroscopic problems concerning octahedral or tetrahedral molecules. Particular attention has been put on careful phase choices. A numerical calculation of all the G matrix elements for both integer and half-integer j values up to 399/2 has been performed. Such high angular momentum values are necessary for the case of heavy molecules with high rotational excitation. To calculat…
Strongly correlated states of trapped ultracold fermions in deformed Landau levels
2015
We analyze the strongly correlated regime of a two-component trapped ultracold fermionic gas in a synthetic non-Abelian U(2) gauge potential, that consists of both a magnetic field and a homogeneous spin-orbit coupling. This gauge potential deforms the Landau levels (LLs) with respect to the Abelian case and exchanges their ordering as a function of the spin-orbit coupling. In view of experimental realizations, we show that a harmonic potential combined with a Zeeman term, gives rise to an angular momentum term, which can be used to test the stability of the correlated states obtained through interactions. We derive the Haldane pseudopotentials (HPs) describing the interspecies contact inte…
Algebraic Treatment of a Three-Oscillator System: Applications to Some Molecular Models
1997
Abstract A new algebraic treatment of a three-oscillator system, called 3d formalism, is proposed. First, arbitrary tensor operators, expressed in terms of elementary creation and annihilation boson operators, are built within the standard algebraic chain u (3) ⊃ so (3) ⊃ so (2). Their matrix elements are next derived in a standard basis. Some applications, which require few adaptions or extensions, are proposed. They allow one to recover, for instance, Hecht's and tetrahedral Hamiltonians associated with threefold degenerate modes of spherical molecules and the vibron model Hamiltonian introduced for diatomic molecules.
Structure formation during an early period of matter domination
2014
In this work we show that modifying the thermal history of the Universe by including an early period of matter domination can lead to the formation of astronomical objects. However, the survival of these objects can only be possible if the dominating matter decays to a daughter particle which is not only almost degenerate with the parent particle but also has an open annihilation channel. This requirement translates in an upper bound for the coupling of such a channel and makes the early structure formation viable.
Baryon Properties with Three-Quark Forces
1987
The Constituent Quark Model (CQM) is very useful for the description of many baryon properties, leading to a fair agreement with the experimental data, especially in the case of the baryon spectrum 1) and of the electromagnetic processes involving baryons2,3). The model is based on a non relativistic QCD-inspired dynamics, which includes a confinement potential and a spin-dependent short-range part, the so called hyperfine interaction4,1). The confinement potential contains as its major part a harmonic oscillator (h.o.) interaction, which has however a too degenerate spectrum with respect to the experimental one and leads to an unreasonable damping of the form factors even at moderate momen…
A note on static metrics: the degenerate case
2013
We give the necessary and sufficient conditions for a 3-metric to be the adapted spatial metric of a static vacuum solution. This work accomplishes for the degenerate cases the already known study for the regular ones (Bartnik and Tod 2006 {\it Class. Quantum Grav.} {\bf 23} 569-571).
Creating highly squeezed vacua in hybrid Laguerre-Gauss modes
2009
In this communication we study the above threshold quantum properties of a degenerate optical parametric oscillator (DOPO) tuned to a given transverse mode family at the signal frequency. We will show that under this configuration DOPOs are versatile sources of nonclassical light, in which one could be able to generate highly squeezed vacua with the non trivial shapes of Hybrid Laguerre-Gauss modes.
Multivalued solutions for the output intensity of a semilinear photorefractive oscillator and stability analysis
2007
The analysis of pump-ratio dependences of the output intensity for a semilinear photorefractive coherent oscillator reveals two domains of multivalued solutions for sufficiently large coupling strength ensured by the crystal. We show that even in a strictly degenerate case the nonzero output intensity can be reached in a broad range of pump ratios r from 10−6 to infinity, including the interval where both pump intensities coincide or are very close to each other. This does not contradict the existence of the known gap in the oscillation threshold near the equal intensities of two pump waves: in this particular region the oscillation is not self-starting. The output intensities for frequency…
Ising-Bloch transition in 2D degenerate wave mixing
2004
We show experimentally and theoretically the existence of a 2D Ising-Bloch transition in the field generated by degenerate four wave mixing in a BaTiO3-resonator.