We investigate the possible thermodynamic instability in a warm and dense nuclear medium where a phase transition from nucleonic matter to resonance-dominated Δ-matter can take place. Such a phase transition is characterized by both mechanical instability (fluctuations on the baryon density) and by chemical-diffusive instability (fluctuations on the isospin concentration) in asymmetric nuclear matter. Similarly to the liquid-gas phase transition, the nucleonic and the Δ-matter phase have a different isospin density in the mixed phase. In the liquid-gas phase transition, the process of producing a larger neutron excess in the gas phase is referred to as isospin fractionation. A similar effects can occur in the nucleon- Δmatter phase transition due essentially to a Δ- excess in the Δ-matter phase in asymmetric nuclear matter. In this context we also discuss the relevance of Δ-isobar degrees of freedom in the bulk properties and in the maximum mass of compact stars.

Thermodynamic Instability in Warm and Dense Asymmetric Nuclear Matter

GERVINO, Gianpiero;
2016-01-01

Abstract

We investigate the possible thermodynamic instability in a warm and dense nuclear medium where a phase transition from nucleonic matter to resonance-dominated Δ-matter can take place. Such a phase transition is characterized by both mechanical instability (fluctuations on the baryon density) and by chemical-diffusive instability (fluctuations on the isospin concentration) in asymmetric nuclear matter. Similarly to the liquid-gas phase transition, the nucleonic and the Δ-matter phase have a different isospin density in the mixed phase. In the liquid-gas phase transition, the process of producing a larger neutron excess in the gas phase is referred to as isospin fractionation. A similar effects can occur in the nucleon- Δmatter phase transition due essentially to a Δ- excess in the Δ-matter phase in asymmetric nuclear matter. In this context we also discuss the relevance of Δ-isobar degrees of freedom in the bulk properties and in the maximum mass of compact stars.
2016
Nuclear Physics and Astrophysics IV: 26-th Nuclear Physics Divisional Conference of the European Physical Society
Lisbon (Portugal)
May 19-24, 2013
665
-
1
4
Astrophysics; Degrees of freedom (mechanics); Gases; Liquefied gases; Stars; Thermodynamic stability
A. lavagno; G. Gervino; D. Pigato
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1502616
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