AN IMPROVED MODEL FOR THE MULTIPLICITY FUNCTION

2005 ◽  
Vol 14 (10) ◽  
pp. 1779-1791
Author(s):  
ANTONINO DEL POPOLO
Keyword(s):  
Angular Momentum ◽  
Cosmological Constant ◽  
Total Angular Momentum ◽  
Theoretical Background ◽  
Multiplicity Function ◽  
Excursion Set ◽  
Improved Model ◽  
Function Models

I compare the numerical multiplicity function given in Ref. 35 with the theoretical multiplicity function obtained by means of the excursion set model and an improved version of the barrier shape obtained in Ref. 7, which implicitly takes account of total angular momentum acquired by the proto-structure during evolution and of a non-zero cosmological constant. I show that the multiplicity function obtained in the present paper is in better agreement with the simulations of Yahagi, Nagashima and Yoshii35 than other previous models16,29–31 and that unlike some previous multiplicity function models16,35 it was obtained from a sound theoretical background.

scholarly journals A precise mass function in the excursion set approach

2017 ◽  
Vol 26 (1) ◽  
Author(s):  
Antonino Del Popolo
Keyword(s):  
Angular Momentum ◽  
Cosmological Constant ◽  
Mass Range ◽  
Mass Function ◽  
Dynamical Friction ◽  
Spherical Collapse ◽  
Collapse Model ◽  
Virial Mass ◽  
Excursion Set ◽  
Good Agreement

AbstractIn the present paper, using previous results from Del Popolo papers, we show how the mass function evolution can be obtained in the framework of a spherical collapse model, which has been modified to take account of dynamical friction, the cosmological constant, and angular momentum which proto-structures acquire through tidal interaction with neighbouring ones. We found an improved barrier which is in excellent agreement with simulations. The quoted barrier is used to calculated the mass function. In the case of the ΛCDM paradigm, our mass function is in good agreement (within some %) with the mass function of Klypin’s Bolshoi simulation for the virial mass range 5 × 10

EVOLUTION OF THE COSMOLOGICAL MASS FUNCTION IN A MOVING BARRIER MODEL

2006 ◽  
Vol 15 (05) ◽  
pp. 703-715
Author(s):  
ANTONINO DEL POPOLO
Keyword(s):  
Numerical Simulation ◽  
Dark Matter ◽  
Angular Momentum ◽  
High Resolution ◽  
Total Angular Momentum ◽  
Dwarf Galaxies ◽  
Mass Function ◽  
Λcdm Model ◽  
Excursion Set ◽  
Barrier Model

We calculate the mass function evolution in a ΛCDM model by means of the excursion set model and an improved version of the barrier shape obtained in Del Popolo and Gambera [Astron. Astrophys.337, 96 (1998)], which implicitly takes account of total angular momentum acquired by the protostructure during evolution and of a nonzero cosmological constant. We compare the result with Reed et al. [Mon. Not. R. Astron. Soc.346, 565 (2003)], who used a high-resolution ΛCDM numerical simulation to calculate the mass function of dark matter haloes down to the scale of dwarf galaxies, back to a redshift of 15. We show that the mass function obtained in the present paper gives similar predictions to the Sheth and Tormen mass function, but it does not show the overprediction of extremely rare objects shown by the Sheth and Tormen mass function. The results confirm previous findings that the simulated halo mass function can be described solely by the variance of the mass distribution, and thus has no explicit redshift dependence.

scholarly journals Total Angular Momentum Dichroism of the Terahertz Vortex Beams at the Antiferromagnetic Resonances

2021 ◽  
Vol 126 (15) ◽  
Author(s):  
A. A. Sirenko ◽  
P. Marsik ◽  
L. Bugnon ◽  
M. Soulier ◽  
C. Bernhard ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Total Angular Momentum ◽  
Vortex Beams

SYMMETRY DECOUPLING IN LINEAR ALGEBRAIC VARIATIONAL SCATTERING PROBLEMS

1995 ◽  
Vol 06 (01) ◽  
pp. 105-121
Author(s):  
MEISHAN ZHAO
Keyword(s):  
Angular Momentum ◽  
Variational Principle ◽  
Total Angular Momentum ◽  
Numerical Calculations ◽  
Quantum Mechanical ◽  
Matrix Elements ◽  
Scattering Problems ◽  
Identical Particles ◽  
Generalized Newton

This paper discusses the symmetry decoupling in quantum mechanical algebraic variational scattering calculations by the generalized Newton variational principle. Symmetry decoupling for collisions involving identical particles is briefly discussed. Detailed discussion is given to decoupling from evaluation of matrix elements with nonzero total angular momentum. Example numerical calculations are presented for BrH2 and DH2 systems to illustrate accuracy and efficiency.

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