Harmonic expansion of the effective potential in a functional renormalization group at finite chemical potential

Barnaföldi, G. G.; Jakovác, Antal; Pósfay, Péter

doi:10.1103/physrevd.95.025004

Cited by 11 publications

(12 citation statements)

References 28 publications

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“…Based on Pósfay et al (2015) and Barnaföldi et al (2017aBarnaföldi et al ( , 2017b using the FRG method we calculated the effect of bosonic quantum fluctuations on neutron star observables considering the simplest interacting Fermi-gas model and compared our results to some other similar model EoS as well. We concluded that high-order calculations are needed for the consistency between the phase diagram and the observable quantities such as the mass and radius of compact stars, compactness, and thermodynamical quantities like compressibility.…”

Section: Resultsmentioning

confidence: 99%

“…Based on these calculations one can argue, that using mean field models is enough to study the neutron star data, since it is so close to the high order calculation. However, one has to be careful with such a prediction because as shown by Barnaföldi et al (2017b) the phase diagram of the model behaves differently in various approximations. The analyzed phase structure shows about 30% difference between the mean field and high order calculations.…”

Section: The Effect Of Fluctuations On Compactnessmentioning

confidence: 99%

“…Note that these uncertainty bars were taken based on Ozel et al (2016a); however, we note mass-only measurement alone can be more accurate, due to the Shapiro-delay-based precise measurements (Demorest et al 2010;van Kerkwijk, Breton, & Kulkarni 2011). Using the demonstrative model described in Barnaföldi et al (2017b), we can estimate whether or not the effect of quantum fluctuations on compact star observables can be detected by modern data analysis methods. For the estimation, we assume that the relative size of the effect of fluctuations remains the same in more realistic models of neutron stars.…”

Section: The Effect Of Fluctuations On Compactnessmentioning

confidence: 99%

See 2 more Smart Citations

The Effect of Quantum Fluctuations in Compact Star Observables

Pósfay

Barnaföldi

Jakovác

2018

Publ. Astron. Soc. Aust.

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Astrophysical measurements regarding compact stars are just ahead of a big evolution jump, since the NICER experiment deployed on ISS on 14 th June 2017. This will provide soon data that would enable the determination of compact star radius with less than 10 % error. This can be further constrained by the new observation of gravitational waves originated from merging neutron stars, GW170817. This poses new challenges to nuclear models aiming to explain the structure of super dense nuclear matter found in neutron stars.A detailed studies of the QCD phase diagram shows the importance of bosonic quantum fluctuations in the cold dense matter equation of state. Here we used a demonstrative model with one bosonic and one fermionic degree of freedom coupled by Yukawa coupling we show the effect of bosonic quantum fluctuations on compact star observables such as mass, radius and compactness.We have also calculated the difference in the value of compressibility which is caused by quantum fluctuations. The above mentioned quantities are calculated in mean field, one-loop and in high order many loop approximation. The results show that the magnitude of these effects is in the range of 4-5 %, which place it into the region where modern measurements may detect it. This forms a base for further investigations that how these results carry over to more complicated models.

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Section: Resultsmentioning

confidence: 99%

Section: The Effect Of Fluctuations On Compactnessmentioning

confidence: 99%

Section: The Effect Of Fluctuations On Compactnessmentioning

confidence: 99%

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The Effect of Quantum Fluctuations in Compact Star Observables

Pósfay

Barnaföldi

Jakovác

2018

Publ. Astron. Soc. Aust.

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“…Solving the T = 0 flow equation exactly could also provide some new analytical and numerical insights. Some efforts in this direction have been done in [67], where the authors try to solve the flow equation at T = 0 by executing a mathematical transformation to the differential equations in order to transform the rectangular initial condition on a circular one, due to the Fermi sphere.…”

Section: Discussionmentioning

confidence: 99%

Functional renormalization group study of the critical region of the quark-meson model with vector interactions

2020

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The critical region of the two flavour quark-meson model with vector interactions is explored using the Functional Renormalization Group, a non-perturbative method that takes into account quantum and thermal fluctuations. Special attention is given to the low temperature and high density region of the phase diagram, which is very important to construct the equation of state of compact stars. As in previous studies, without repulsive vector interaction, an unphysical region of negative entropy density is found near the first order chiral phase transition. We explore the connection between this unphysical region and the chiral critical region, especially the first order line and spinodal lines, using also different values for vector interactions. We find that the unphysical negative entropy density region appears because the $$s=0$$s=0 isentropic line, near the critical region, is displaced from its $$T=0$$T=0 location. For certain values of vector interactions this region is pushed to lower temperatures and high chemical potentials in such way that the negative entropy density region on the phase diagram can even disappear. In the case of finite vector interactions, the location of the critical end point has a non-trivial behaviour in the $$T-\mu _B$$T-μB plane, which differs from that in mean field calculations.

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“…Thus, effective theories play an important role in studying the properties of cold dense nuclear matter [14,15]. Recent studies show the importance of the correct handling of the bosonic sector in effective theories of nuclear matter [16,17], moreover, applying the functional renormalization group (FRG) method on the simplest non-trivial nuclear matter, the effect of the microscopical parameters on neutron star observables were shown in Refs. [18,19].…”

Section: Introductionmentioning

confidence: 99%

Estimating the Variation of Neutron Star Observables by Dense Symmetric Nuclear Matter Properties

2019

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Recent multi-channel astrophysics observations and the soon-to-be published new measured electromagnetic and gravitation data provide information on the inner structure of the compact stars. These macroscopic observations can significantly increase our knowledge on the neutron star enteriors, providing constraints on the microscopic physical properties. On the other hand, due to the masquarade problem, there are still uncertainties on the various nuclear-matter models and their parameters as well. Calculating the properties of the dense nuclear matter, effective field theories are the most widely-used tools. However the values of the microscopical parameters need to be set consistently to the nuclear and astrophysical measurements. In this work we investigate how uncertainties are induced by the variation of the microscopical parameters. We use a symmetric nuclear matter in an extended σ-ω model. We calculate the dense matter equation of state and give the mass-radius diagram. We present that the Landau mass and compressibility modulus of the nuclear matter have definite linear relation to the maximum mass of a Schwarzschild neutron star.

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Harmonic expansion of the effective potential in a functional renormalization group at finite chemical potential

Cited by 11 publications

References 28 publications

The Effect of Quantum Fluctuations in Compact Star Observables

The Effect of Quantum Fluctuations in Compact Star Observables

Functional renormalization group study of the critical region of the quark-meson model with vector interactions

Estimating the Variation of Neutron Star Observables by Dense Symmetric Nuclear Matter Properties

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