About NagBody (Numerical Algorithms for General Body Dynamics) - or Physics with particles
To understand the behavior of nature, the phenomena that we observe, we proceed by mimicking the real system. The copy, our model, is formed by a set of "particles" that evolve according to the force produced by the others or by external forces or boundaries. A "Particle" forming our system is a general concept, can be a real particle, like an electron, atom or molecule, or can be a collective mode in a solid or liquid, or even a car in a highway, a person in a stadium, or a bird in a flock.
This is the main concept behind NagBody, i.e., the concept of a general particle or body. To study a system composed by this general particles or bodies we need to develop a set of numerical codes capable to set initial conditions, boundaries and external forces, simulate its evolution in time, and to show a snapshot of it at a given time.
NagBody came to live due to my own numerical necessities during years of research in diverse fields of physics: hot electron in semiconductors, chaotic electron transport through corrugated channels, dispersions of micro-particles in a turbulent fluid, galactic dynamics and scalar fields in gravity.
NagBody is based on the Barnes Hierarchical treecode and follows a variant of the unifying idea of his Zeno library and the Teuben Nemo toolbox. NagBody is a modest set (as compared to Teuben Nemo toolbox) of numerical codes with the purpose to help me in my research problems and I hope it will be helpful to other people working in similar fields of research (or even others). However, at the moment, I am unifiying the functionality of the numerical codes in order to complain with my own variant of the Nemo project. That is the reason, this time, I just describe here the group of codes to simulate galactic dynamics under the influence of scalar fields in its Newtonian limit: the integrator (gbsph); a direct N-body code (nbody_n2); a code to generate various models (models); a code to generate a Bulge-Disk-Halo galaxy; a code to analyze snapshot data (datanaly). Also included are codes to simulate molecular dynamics of a Lennard-Jones liquid (md_lj_tree, md_lj_n2).
The seeds that are giving life to NagBody gave results that were published in the past, see for example:
The influence of numerical parameters on tidally triggered bar formation. R. Gabbasov, M.A. Rodríguez-Meza, J.L. Cervantes-Cota, and J. Klapp. Astron. & Astrophys. 449, 1043-1059 (2006). (PDF File 17 pages).
The influence of non-minimally coupled scalar fields on the dynamics of interacting galaxies. R. Gabbasov, M.A. Rodríguez-Meza, J.L. Cervantes-Cota, and J. Klapp. Rev. Mex. Fis. In press (2006).
Potential-density pairs for axisymmetric galaxies: the influence of scalar fields. M.A. Rodríguez-Meza, J.L. Cervantes-Cota, M.I. Pedraza, J.F. Tlapanco, and E.M. De la Calleja, Gen. Rel. Grav. 37, 823-829 (2005).
Kinetic theory of thermotransport of degenerate polar semiconductor electrons. A. Rangel-Huerta, R.M. Velasco, and M.A. Rodríguez-Meza. Physica A 349 202-220 (2005). (PDF file 20 pages).
Potential-density pairs for spherical galaxies and bulges: the influence of scalar fields. M.A. Rodríguez-Meza and J.L. Cervantes-Cota, Mon. Not. R. Astron. Soc. 350, 671-678 (2004). (PDF file 6 pages).
Velocity autocorrelation function of a dispersion of heavy particles in a turbulent flow: On the effect of interparticle collisions. R. Avila and M.A. Rodríguez-Meza, Rev. Mex. Fis. 50, 156-161 (2004). (PDF file 11 pages).
Kinetic approach for the calculation of the thermopower coefficient in semiconductor heterostructure. M.A. Rodríguez-Meza, J.L. Carrillo, and A. Rangel-Huerta. Physica A 328, 154-166 (2003). (PDF file 16 pages).
The transfer of angular momentum between interacting galaxies. R. Gabbasov, J. Klapp, M.A. Rodríguez-Meza, J.L. Cervantes-Cota, H. Dehnen, Rev. Mex. Astron. Astrofísica (Serie de Conferencias) 17, 101 (2003). (PDF file 1 page).
El método del SPH y sus aplicaciones. M.A. Rodríguez-Meza. Informe Técnico ININ CB-014/2002 (2002). (PDF file 111 pages).
The influence of scalar fields in protogalactic interactions. M.A. Rodríguez-Meza, J.L. Cervantes-Cota, J. Klapp, and H. Dehnen. In: Exact Solutions and Scalar Fields in Gravity: Recent Developments. Edited by A. Macias, J. Cervantes, and C. Laemmerzahl. (Kluwer Academic/Plenum Publisher, New York, 2001). Pags. 213-221. (PDF file 11 pages).
Hidrodinámica de Partículas Suavizadas. M.A. Rodríguez-Meza. ININ (2000). In spanish.
Classical chaos and ballistic transport in a mesoscopic channel. G.A. Luna-Acosta, A.A. Krokhin, M.A. Rodríguez, and P.H. Hernández-Tejeda, Phys. Rev. B54, 11410-11416 (1996). (PDF file).
A Model for Hot Electron Phenomena: Theory and General Results. J.L. Carrillo and M.A. Rodríguez, Phys. Rev. B44 2934-2945 (1991). (PDF file).
