scholarly journals Halo Properties in Helium Nuclei From the Perspective of Geometrical Thermodynamics

2020 ◽  
Author(s):  
Michael Parker ◽  
Chris Jeynes ◽  
Wilton Catford
Keyword(s):  
Ground State ◽  
Degrees Of Freedom ◽  
Characteristic Length ◽  
The Self ◽  
Neutron Halo ◽  
Helium Isotopes ◽  
Centre Of Mass ◽  
Characteristic Length Scale ◽  
Charge Radii ◽  
Weak Binding

Abstract The nuclear matter and charge radii of the helium isotopes (A=4,6,8) are calculated by quantitative geometrical thermodynamics (QGT) taking as input the symmetry of the a‑particle, the very weak binding (and hence halo nature) of the heavier helium isotopes, and a characteristic length scale given by the proton size. The results follow by considering each isotope in its ground state, with QGT representing each system as a maximum entropy configuration that conforms to the Holographic Principle. This allows key geometric parameters to be determined from the number of degrees of freedom available.QGT treats 6He as a 4He core plus a concentric neutron shell comprising a holomorphic pair of neutrons, and the 8He neutron halo is treated as a holomorphic pair of holomorphic pairs. Considering the information content of each system allows a correlation angle of 2/3 between the holomorphic entities to be inferred, and then the charge radii of the three isotopes can be calculated from the displacement of the 4He core from the centre of mass. The calculations for the charge and matter radii of 4,6,8He agree closely with observed values. Similar QGT calculation of the sizes of the self-conjugate A=4n nuclei {4He,8Be,12C,16O,20Ne,24Mg,28Si,32S,36Ar,40Ca} also agree well with experiment.

scholarly journals Halo Properties in Helium Nuclei from the Perspective of Geometrical Thermodynamics

2021 ◽  
Author(s):  
M. C. Parker ◽  
C. Jeynes ◽  
W. N. Catford
Keyword(s):  
Ground State ◽  
Degrees Of Freedom ◽  
Characteristic Length ◽  
The Self ◽  
Neutron Halo ◽  
Helium Isotopes ◽  
Centre Of Mass ◽  
Characteristic Length Scale ◽  
Charge Radii ◽  
Weak Binding

Abstract The nuclear matter and charge radii of the helium isotopes (A = 4,6,8) are calculated by quantitative geometrical thermodynamics (QGT) taking as input the symmetry of the alpha-particle, the very weak binding (and hence halo nature) of the heavier helium isotopes, and a characteristic length scale given by the proton size. The results follow by considering each isotope in its ground state, with QGT representing each system as a maximum entropy configuration that conforms to the Holographic Principle. This allows key geometric parameters to be determined from the number of degrees of freedom available. QGT treats 6He as a 4He core plus a concentric neutron shell comprising a holomorphic pair of neutrons, and the 8He neutron halo is treated as a holomorphic pair of holomorphic pairs. Considering the information content of each system allows a correlation angle of 2pi/3 between the holomorphic entities to be inferred, and then the charge radii of the three isotopes can be calculated from the displacement of the 4He core from the centre of mass. The calculations for the charge and matter radii of 4,6,8He agree closely with observed values. Similar QGT calculation of the sizes of the self-conjugate A = 4n nuclei {4He,8Be,12C,16O,20Ne,24Mg,28Si,32S,36Ar,40Ca} also agree well with experiment.

scholarly journals Halo Properties in Helium Nuclei From the Perspective of Geometrical Thermodynamics

2020 ◽  
Author(s):  
Michael Parker ◽  
Chris Jeynes ◽  
Wilton Catford
Keyword(s):  
Ground State ◽  
Degrees Of Freedom ◽  
Characteristic Length ◽  
The Self ◽  
Neutron Halo ◽  
Helium Isotopes ◽  
Centre Of Mass ◽  
Characteristic Length Scale ◽  
Charge Radii ◽  
Weak Binding

Abstract The nuclear matter and charge radii of the helium isotopes (A=4,6,8) are calculated by quantitative geometrical thermodynamics (QGT) taking as input the symmetry of the a‑particle, the very weak binding (and hence halo nature) of the heavier helium isotopes, and a characteristic length scale given by the proton size. The results follow by considering each isotope in its ground state, with QGT representing each system as a maximum entropy configuration that conforms to the Holographic Principle. This allows key geometric parameters to be determined from the number of degrees of freedom available.QGT treats 6He as a 4He core plus a concentric neutron shell comprising a holomorphic pair of neutrons, and the 8He neutron halo is treated as a holomorphic pair of holomorphic pairs. Considering the information content of each system allows a correlation angle of 2/3 between the holomorphic entities to be inferred, and then the charge radii of the three isotopes can be calculated from the displacement of the 4He core from the centre of mass. The calculations for the charge and matter radii of 4,6,8He agree closely with observed values. Similar QGT calculation of the sizes of the self-conjugate A=4n nuclei {4He,8Be,12C,16O,20Ne,24Mg,28Si,32S,36Ar,40Ca} also agree well with experiment.

scholarly journals Scaling and similarity of a stream-power incision and linear diffusion landscape evolution model

2018 ◽  
Author(s):  
Nikos Theodoratos ◽  
Hansjörg Seybold ◽  
James W. Kirchner
Keyword(s):  
Steady State ◽  
Degrees Of Freedom ◽  
Characteristic Length ◽  
Initial Conditions ◽  
Model Parameters ◽  
Length Scale ◽  
Characteristic Length Scale ◽  
Stream Power ◽  
Linear Diffusion ◽  
Characteristic Scales

Abstract. Scaling and similarity of fluvial landscapes can reveal fundamental aspects of the physics driving their evolution. Here we perform dimensional analysis on a widely used landscape evolution model (LEM) that combines stream-power incision and linear diffusion laws. Our analysis assumes that length and height are conceptually distinct dimensions, and uses characteristic scales that depend only on the model parameters (incision coefficient, diffusion coefficient, and uplift rate) rather than on the size of the domain or of landscape features. We use a previously defined characteristic length scale, but introduce new characteristic height and time scales. We use these characteristic scales to non-dimensionalize the LEM, such that it includes only dimensionless variables and no parameters. This significantly simplifies the LEM by removing all parameter-related degrees of freedom. The only remaining degrees of freedom are in the boundary and initial conditions. Thus, for any given set of dimensionless boundary and initial conditions, all simulations, regardless of parameters, are just re-scaled copies of each other, both in steady state and throughout their evolution. Therefore, the entire model parameter space can be explored by temporally and spatially re-scaling a single simulation. This is orders of magnitude faster than performing multiple simulations to span multi-dimensional parameter spaces. The characteristic length, height, and time scales are geomorphologically interpretable; they define relationships between topography and the relative strengths of landscape-forming processes. The characteristic height scale specifies how drainage areas and slopes must be related to curvatures for a landscape to be in steady state, and leads to methods for defining valleys, estimating model parameters, and testing whether real topography follows the LEM. The characteristic length scale is roughly equal to the scale of the transition from diffusion-dominated to advection-dominated propagation of topographic perturbations (e.g., knickpoints). We introduce a modified definition of the landscape Péclet number, which quantifies the relative influence of advective versus diffusive propagation of perturbations. Our Péclet number definition can account for the scaling of basin length with basin area, which depends on topographic convergence versus divergence.

Identification of the characteristic length scale for fatigue cracking in fretting contacts

1998 ◽  
Vol 08 (PR8) ◽  
pp. Pr8-159-Pr8-166 ◽  
Author(s):  
S. Fouvry ◽  
Ph. Kapsa ◽  
F. Sidoroff ◽  
L. Vincent
Keyword(s):  
Characteristic Length ◽  
Fatigue Cracking ◽  
Length Scale ◽  
Characteristic Length Scale

Charge Transfer Between CO22+ and Ar or Ne at Collision Energies 3-10 eV

2003 ◽  
Vol 68 (1) ◽  
pp. 178-188 ◽  
Author(s):  
Libor Mrázek ◽  
Ján Žabka ◽  
Zdeněk Dolejšek ◽  
Zdeněk Herman
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Ground State ◽  
Scattering Method ◽  
Translational Energy ◽  
Centre Of Mass ◽  
Energy Distributions ◽  
Zener Model ◽  
Beam Scattering ◽  
Product Ions

The beam scattering method was used to investigate non-dissociative single-electron charge transfer between the molecular dication CO22+ and Ar or Ne at several collision energies between 3-10 eV (centre-of-mass, c.m.). Relative translational energy distributions of the product ions showed that in the reaction with Ar the CO2+ product was mainly formed in reactions of the ground state of the dication, CO22+(X3Σg-), leading to the excited states of the product CO2+(A2Πu) and CO2+(B2Σu+). In the reaction with Ne, the largest probability had the process from the reactant dication excited state CO22+(1Σg+) leading to the product ion ground state CO2+(X2Πg). Less probable were processes between the other excited states of the dication CO22+, (1∆g), (1Σu-), (3∆u), also leading to the product ion ground state CO2+(X2Πg). Using the Landau-Zener model of the reaction window, relative populations of the ground and excited states of the dication CO22+ in the reactant beam were roughly estimated as (X3Σg):(1∆g):(1Σg+):(1Σu-):(3∆u) = 1.0:0.6:0.5:0.25:0.25.

scholarly journals Lettau’s Contribution to the Obukhov Length Scale: A Scientific Historical Study

2021 ◽  
Author(s):  
Thomas Foken ◽  
Michael Börngen
Keyword(s):  
Characteristic Length ◽  
Stability Parameter ◽  
Historical Study ◽  
Length Scale ◽  
Characteristic Length Scale ◽  
Obukhov Length ◽  
The Future

AbstractIt has been repeatedly assumed that Heinz Lettau found the Obukhov length in 1949 independently of Obukhov in 1946. However, it was not the characteristic length scale, the Obukhov length L, but the ratio of height and the Obukhov length (z/L), the Obukhov stability parameter, that he analyzed. Whether Lettau described the parameter z/L independently of Obukhov is investigated herein. Regardless of speculation about this, the significant contributions made by Lettau in the application of z/L merit this term being called the Obukhov–Lettau stability parameter in the future.

Mesonic and isobar degrees of freedom in the ground state of the nuclear many-body system

1978 ◽  
Vol 18 (5) ◽  
pp. 2416-2429 ◽  
Author(s):  
M. R. Anastasio ◽  
Amand Faessler ◽  
H. Müther ◽  
K. Holinde ◽  
R. Machleidt
Keyword(s):  
Ground State ◽  
Degrees Of Freedom ◽  
Body System ◽  
Many Body

scholarly journals Impact of uncertainties of unbound 10Li on the ground state of two-neutron halo 11Li

2020 ◽  
Author(s):  
Jagit Singh ◽  
Wataru Horiuchi
Keyword(s):  
Ground State ◽  
Halo Nucleus ◽  
Transfer Reaction ◽  
Neutron Halo ◽  
Structure Model ◽  
Continuum States ◽  
Normal Core ◽  
Configuration Mixing ◽  
Three Body ◽  
Neutron Transfer Reaction

Recently, the energy spectrum of \boldsymbol{^{10}}10Li was measured upto \boldsymbol{4.6}4.6 MeV, via one-neutron transfer reaction \boldsymbol{d(^{9}\textrm{Li},~p)^{10}\textrm{Li}}𝐝(9Li,𝐩)10Li. Considering the ambiguities on the \boldsymbol{^{10}}10Li continuum spectrum with reference to new data, we report the configuration mixing in the ground state of the two-neutron halo nucleus \boldsymbol{^{11}}11Li for two different choices of the \boldsymbol{^{9}{\textrm{Li}}+n}9Li+𝐧 potential. For the present study, we employ a three-body (\boldsymbol{\textrm{core}+n+n}core+𝐧+𝐧) structure model developed for describing the two-neutron halo system by explicit coupling of unbound continuum states of the subsystem (\boldsymbol{\textrm{core}+n}core+𝐧), and discuss the two-neutron correlations in the ground state of \boldsymbol{^{11}}11Li.

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