Abstract:
Ideal nuclear matter is expected to undergo a first order phase transition at the thermodynamic limit. At such phase transitions the size of density fluctuations (bubbles or droplets) scale with the size of the system. This means that simulations of nuclear matter at sub-saturation densities will inexorably suffer from what is vaguely referred to as "finite size effects". It is usually thought that these finite size effects can be diminished by imposing periodic boundary conditions and making the system large enough, but as we show in this work, that is actually not the case at sub-saturation densities. In this paper we analyze the equilibrium configurations of molecular dynamics simulations of a classical model for symmetric ideal (uncharged) nuclear matter at sub-saturation densities and low temperatures, where phase coexistence is expected at the thermodynamic limit. We show that the most stable configurations in this density range are almost completely determined by artificial aspects of the simulations (i.e. boundary conditions) and can be predicted analytically by surface minimization. This result is very general and is shown to hold true for several well known semi-classical models of nuclear interaction and even for a simple Lennard-Jones potential. Also, in the limit of very large systems, when "small size" effects can be neglected, those equilibrium configurations seem to be restricted to a few structures reminiscent to the "Pasta Phases" expected in Neutron Star matter, but arising from a completely different origin: In Neutron Star matter, the non-homogeneous structures arise from a competition between nuclear and Coulomb interactions while for ideal nuclear matter they emerge from finite (yet not "small") size effects. The role of periodic boundary conditions and finite size effects in Neutron Star matter simulations are reexamined. © 2014 Elsevier B.V..
Registro:
Documento: |
Artículo
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Título: | Simulations of cold nuclear matter at sub-saturation densities |
Autor: | Giménez Molinelli, P.A.; Nichols, J.I.; López, J.A.; Dorso, C.O. |
Filiación: | Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428, Argentina Department of Physics, University of Texas at El Paso, El Paso, TX 79968, United States
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Palabras clave: | Finite size effects; Molecular dynamics simulations; Nuclear astrophysics; Nuclear matter phase transition |
Año: | 2014
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Volumen: | 923
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Página de inicio: | 31
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Página de fin: | 50
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DOI: |
http://dx.doi.org/10.1016/j.nuclphysa.2014.01.003 |
Título revista: | Nuclear Physics A
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Título revista abreviado: | Nucl. Phys. A
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ISSN: | 03759474
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CODEN: | NUPAB
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Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_03759474_v923_n_p31_GimenezMolinelli |
Referencias:
- Viola, V.E., (2004) Nucl. Phys. A, 734, p. 4879
- Lamb, D.Q., Lattimer, J.M., Pethick, C.J., Ravenhall, D.G., (1984) Nucl. Phys. A, 411, p. 449
- Lattimer, J.M., Pethick, C.J., Ravenhall, D.G., Lamb, D.Q., (1985) Nucl. Phys. A, 432, p. 646
- Lattimer, J.M., Pethick, C.J., (1978) Astrophys. J., 223, p. 314
- Lattimer, J.M., (1981) Annu. Rev. Nucl. Part. Sci., 31, p. 337
- Bonche, P., Vautherin, D., (1981) Nucl. Phys. A, 372, p. 496
- Bonche, P., Levit, S., Vautherin, D., (1984) Nucl. Phys. A, 427, p. 278
- Ravenhall, D.G., Pethick, C.J., Wilson, J.R., (1983) Phys. Rev. Lett., 50, p. 2066
- Williams, R.D., Koonin, S.E., (1985) Nucl. Phys. A, 435, p. 844
- Hashimoto, M., Seki, H., Yamada, M., (1984) Prog. Theor. Phys., 71, p. 320
- Oyamatsu, K., (1993) Nucl. Phys. A, 561, p. 431
- Lorenz, C.P., Ravenhall, D.G., Pethick, C.J., (1993) Phys. Rev. Lett., 70, p. 379
- Cheng, K.S., Yao, C.C., Dai, Z.G., (1997) Phys. Rev. C, 55, p. 2092
- Maruyama, T., Niita, K., Oyamatsu, K., Maruyama, T., Chiba, S., Iwamoto, A., (1998) Phys. Rev. C, 57, p. 655
- Kido, T., Maruyama, T., Niita, K., Chiba, S., (2000) Nucl. Phys. A, p. 877
- Watanabe, G., Iida, K., Sato, K., (2000) Nucl. Phys. A, 676, p. 445
- Watanabe, G., Sato, K., Yasuoka, K., Ebisuzaki, T., (2002) Phys. Rev. C, 66. , 012801(R)
- Watanabe, G., Iida, K., (2003) Phys. Rev. C, 68, p. 045801
- Dorso, C.O., Giménez Molinelli, P.A., López, J.A., (2012) Neutron Star Crust, , Nova Science Publishers, C.A. Bertulani, J. Piekarewicz (Eds.)
- Dorso, C.O., Giménez Molinelli, P.A., López, J.A., (2012) Phys. Rev. C, 86, p. 055805
- Horowitz, C.J., Pérez-García, M.A., Piekarewicz, J., (2004) Phys. Rev. C, 69, p. 045804
- Watanabe, G., Sato, K., Yasuoka, K., Ebisuzaki, T., (2003) Phys. Rev. C, 68, p. 035806
- Pais, H., Stone, J.R., (2012) Phys. Rev. Lett., 109, p. 151101
- Humphrey, W., Dalke, A., Schulten, K., VMD - visual molecular dynamics (1996) J. Mol. Graph., 14 (1), pp. 33-38
- Wilets, L., Henley, E.M., Kraft, M., Mackellar, A.D., (1977) Nucl. Phys. A, 282, p. 342
- Vicentini, A., Jacucci, G., Pandharipande, V.R., (1985) Phys. Rev. C, 31, p. 1783
- Lenk, R.J., Pandharipande, V.R., (1986) Phys. Rev. C, 34, p. 177
- Lenk, R.J., Schlagel, T.J., Pandharipande, V.R., (1990) Phys. Rev. C, 42, p. 372
- Dorso, C.O., Randrup, J., (1988) Phys. Lett. B, 215, p. 611
- Dorso, C.O., Duarte, S., Randrup, J., (1987) Phys. Lett. B, 188, pp. 287-294
- Dorso, C.O., Randrup, J., (1993) Phys. Lett. B, 301, p. 328
- Horowitz, C.J., Pérez-García, M.A., Carriere, J., Berry, D.K., Piekarewicz, J., (2004) Phys. Rev. C, 70, p. 065806
- Horowitz, C.J., Pérez-García, M.A., Berry, D.K., Piekarewicz, J., (2005) Phys. Rev. C, 72, p. 035801
- Piekarewicz, J., Toledo Sánchez, G., (2012) Phys. Rev. C, 85, p. 015807
- Chernomoretz, A., Gingras, L., Larochelle, Y., Beaulieu, L., Roy, R., St-Pierre, C., Dorso, C.O., (2002) Phys. Rev. C, 65, p. 054613
- Barrañón, A., Dorso, C.O., López, J.A., (2007) Nucl. Phys. A, 791, p. 222
- Dorso, C.O., López, J.A., (2001) Phys. Rev. C, 64, p. 027602
- Dorso, C.O., Escudero, C.R., Ison, M., López, J.A., (2006) Phys. Rev. C, 73, p. 044601
- Dorso, C.O., Giménez Molinelli, P.A., López, J.A., (2011) J. Phys. G, Nucl. Part. Phys., 38, p. 115101
- Dorso, C.O., Giménez Molinelli, P.A., López, J.A., (2011) Rev. Mex. Fis., 57 (1), p. 14
- Todd-Rutel, B.G., Pieckarewicz, J., (2005) Phys. Rev. Lett., 95, p. 122501
- Garg, U., (2004) Nucl. Phys. A, 731, p. 3
- Colo, G., (2004) Phys. Rev. C, 70, p. 024307
- Andersen, H.C., (1980) J. Chem. Phys., 72, p. 2384
- Binder, K., Block, B.J., Virnau, P., Tröster, A., (2012) Am. J. Phys., 80, p. 1099
- Frenkel, D., Smit, B., (2012) Understanding Molecular Simulations, , Academic Press
Citas:
---------- APA ----------
Giménez Molinelli, P.A., Nichols, J.I., López, J.A. & Dorso, C.O.
(2014)
. Simulations of cold nuclear matter at sub-saturation densities. Nuclear Physics A, 923, 31-50.
http://dx.doi.org/10.1016/j.nuclphysa.2014.01.003---------- CHICAGO ----------
Giménez Molinelli, P.A., Nichols, J.I., López, J.A., Dorso, C.O.
"Simulations of cold nuclear matter at sub-saturation densities"
. Nuclear Physics A 923
(2014) : 31-50.
http://dx.doi.org/10.1016/j.nuclphysa.2014.01.003---------- MLA ----------
Giménez Molinelli, P.A., Nichols, J.I., López, J.A., Dorso, C.O.
"Simulations of cold nuclear matter at sub-saturation densities"
. Nuclear Physics A, vol. 923, 2014, pp. 31-50.
http://dx.doi.org/10.1016/j.nuclphysa.2014.01.003---------- VANCOUVER ----------
Giménez Molinelli, P.A., Nichols, J.I., López, J.A., Dorso, C.O. Simulations of cold nuclear matter at sub-saturation densities. Nucl. Phys. A. 2014;923:31-50.
http://dx.doi.org/10.1016/j.nuclphysa.2014.01.003