Two Novel Approaches to the Hadron-Quark Mixed Phase in Compact Stars
First-order phase transitions, such as the liquid-gas transition, proceed via formation of structures, such as bubbles and droplets. In strongly interacting compact star matter, at the crust-core transition but also the hadron-quark transition in the core, these structures form different shapes dubb...
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| Format: | Article |
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MDPI AG
2018-09-01
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| Series: | Universe |
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| Online Access: | http://www.mdpi.com/2218-1997/4/9/94 |
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| author | Vahagn Abgaryan David Alvarez-Castillo Alexander Ayriyan David Blaschke Hovik Grigorian |
| author_facet | Vahagn Abgaryan David Alvarez-Castillo Alexander Ayriyan David Blaschke Hovik Grigorian |
| author_sort | Vahagn Abgaryan |
| collection | DOAJ |
| description | First-order phase transitions, such as the liquid-gas transition, proceed via formation of structures, such as bubbles and droplets. In strongly interacting compact star matter, at the crust-core transition but also the hadron-quark transition in the core, these structures form different shapes dubbed “pasta phases”. We describe two methods to obtain one-parameter families of hybrid equations of state (EoS) substituting the Maxwell construction that mimic the thermodynamic behaviour of pasta phase in between a low-density hadron and a high-density quark matter phase without explicitly computing geometrical structures. Both methods reproduce the Maxwell construction as a limiting case. The first method replaces the behaviour of pressure against chemical potential in a finite region around the critical pressure of the Maxwell construction by a polynomial interpolation. The second method uses extrapolations of the hadronic and quark matter EoS beyond the Maxwell point to define a mixing of both with weight functions bounded by finite limits around the Maxwell point. We apply both methods to the case of a hybrid EoS with a strong first order transition that entails the formation of a third family of compact stars and the corresponding mass twin phenomenon. For both models, we investigate the robustness of this phenomenon against variation of the single parameter: the pressure increment at the critical chemical potential that quantifies the deviation from the Maxwell construction. We also show sets of results for compact star observables other than mass and radius, namely the moment of inertia and the baryon mass. |
| first_indexed | 2024-04-11T22:50:52Z |
| format | Article |
| id | doaj.art-95a6a79da06e4d058c46f788d30e63f6 |
| institution | Directory Open Access Journal |
| issn | 2218-1997 |
| language | English |
| last_indexed | 2024-04-11T22:50:52Z |
| publishDate | 2018-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Universe |
| spelling | doaj.art-95a6a79da06e4d058c46f788d30e63f62022-12-22T03:58:35ZengMDPI AGUniverse2218-19972018-09-01499410.3390/universe4090094universe4090094Two Novel Approaches to the Hadron-Quark Mixed Phase in Compact StarsVahagn Abgaryan0David Alvarez-Castillo1Alexander Ayriyan2David Blaschke3Hovik Grigorian4Laboratory for Information Technologies, Joint Institute for Nuclear Research, Joliot-Curie Street 6, Dubna 141980, RussiaBogoliubov Laboratory for Theoretical Physics, Joint Institute for Nuclear Research, Joliot-Curie Street 6, Dubna 141980, RussiaLaboratory for Information Technologies, Joint Institute for Nuclear Research, Joliot-Curie Street 6, Dubna 141980, RussiaBogoliubov Laboratory for Theoretical Physics, Joint Institute for Nuclear Research, Joliot-Curie Street 6, Dubna 141980, RussiaLaboratory for Information Technologies, Joint Institute for Nuclear Research, Joliot-Curie Street 6, Dubna 141980, RussiaFirst-order phase transitions, such as the liquid-gas transition, proceed via formation of structures, such as bubbles and droplets. In strongly interacting compact star matter, at the crust-core transition but also the hadron-quark transition in the core, these structures form different shapes dubbed “pasta phases”. We describe two methods to obtain one-parameter families of hybrid equations of state (EoS) substituting the Maxwell construction that mimic the thermodynamic behaviour of pasta phase in between a low-density hadron and a high-density quark matter phase without explicitly computing geometrical structures. Both methods reproduce the Maxwell construction as a limiting case. The first method replaces the behaviour of pressure against chemical potential in a finite region around the critical pressure of the Maxwell construction by a polynomial interpolation. The second method uses extrapolations of the hadronic and quark matter EoS beyond the Maxwell point to define a mixing of both with weight functions bounded by finite limits around the Maxwell point. We apply both methods to the case of a hybrid EoS with a strong first order transition that entails the formation of a third family of compact stars and the corresponding mass twin phenomenon. For both models, we investigate the robustness of this phenomenon against variation of the single parameter: the pressure increment at the critical chemical potential that quantifies the deviation from the Maxwell construction. We also show sets of results for compact star observables other than mass and radius, namely the moment of inertia and the baryon mass.http://www.mdpi.com/2218-1997/4/9/94quark-hadron phase transitionpasta phasesspeed of soundhybrid compact starsmass-radius relationGW170817 |
| spellingShingle | Vahagn Abgaryan David Alvarez-Castillo Alexander Ayriyan David Blaschke Hovik Grigorian Two Novel Approaches to the Hadron-Quark Mixed Phase in Compact Stars Universe quark-hadron phase transition pasta phases speed of sound hybrid compact stars mass-radius relation GW170817 |
| title | Two Novel Approaches to the Hadron-Quark Mixed Phase in Compact Stars |
| title_full | Two Novel Approaches to the Hadron-Quark Mixed Phase in Compact Stars |
| title_fullStr | Two Novel Approaches to the Hadron-Quark Mixed Phase in Compact Stars |
| title_full_unstemmed | Two Novel Approaches to the Hadron-Quark Mixed Phase in Compact Stars |
| title_short | Two Novel Approaches to the Hadron-Quark Mixed Phase in Compact Stars |
| title_sort | two novel approaches to the hadron quark mixed phase in compact stars |
| topic | quark-hadron phase transition pasta phases speed of sound hybrid compact stars mass-radius relation GW170817 |
| url | http://www.mdpi.com/2218-1997/4/9/94 |
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