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Annala E, Gorda T, Hirvonen J, Komoltsev O, Kurkela A, Nättilä J, Vuorinen A. Strongly interacting matter exhibits deconfined behavior in massive neutron stars. Nat Commun 2023; 14:8451. [PMID: 38114461 PMCID: PMC10730725 DOI: 10.1038/s41467-023-44051-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 11/28/2023] [Indexed: 12/21/2023] Open
Abstract
Neutron-star cores contain matter at the highest densities in our Universe. This highly compressed matter may undergo a phase transition where nuclear matter melts into deconfined quark matter, liberating its constituent quarks and gluons. Quark matter exhibits an approximate conformal symmetry, predicting a specific form for its equation of state (EoS), but it is currently unknown whether the transition takes place inside at least some physical neutron stars. Here, we quantify this likelihood by combining information from astrophysical observations and theoretical calculations. Using Bayesian inference, we demonstrate that in the cores of maximally massive stars, the EoS is consistent with quark matter. We do this by establishing approximate conformal symmetry restoration with high credence at the highest densities probed and demonstrating that the number of active degrees of freedom is consistent with deconfined matter. The remaining likelihood is observed to correspond to EoSs exhibiting phase-transition-like behavior, treated as arbitrarily rapid crossovers in our framework.
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Affiliation(s)
- Eemeli Annala
- Department of Physics and Helsinki Institute of Physics, University of Helsinki, P.O. Box 64, FI-00014, University of Helsinki, Finland
| | - Tyler Gorda
- Technische Universität Darmstadt, Department of Physics, 64289, Darmstadt, Germany.
- ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291, Darmstadt, Germany.
| | - Joonas Hirvonen
- Department of Physics and Helsinki Institute of Physics, University of Helsinki, P.O. Box 64, FI-00014, University of Helsinki, Finland.
| | - Oleg Komoltsev
- Faculty of Science and Technology, University of Stavanger, 4036, Stavanger, Norway.
| | - Aleksi Kurkela
- Faculty of Science and Technology, University of Stavanger, 4036, Stavanger, Norway.
| | - Joonas Nättilä
- Center for Computational Astrophysics, Flatiron Institute, 162 Fifth Avenue, New York, NY, 10010, USA.
- Physics Department and Columbia Astrophysics Laboratory, Columbia University, 538 West 120th Street, New York, NY, 10027, USA.
| | - Aleksi Vuorinen
- Department of Physics and Helsinki Institute of Physics, University of Helsinki, P.O. Box 64, FI-00014, University of Helsinki, Finland.
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Novario SJ, Lonardoni D, Gandolfi S, Hagen G. Trends of Neutron Skins and Radii of Mirror Nuclei from First Principles. PHYSICAL REVIEW LETTERS 2023; 130:032501. [PMID: 36763401 DOI: 10.1103/physrevlett.130.032501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 04/04/2022] [Accepted: 12/13/2022] [Indexed: 06/18/2023]
Abstract
The neutron skin of atomic nuclei impacts the structure of neutron-rich nuclei, the equation of state of nucleonic matter, and the size of neutron stars. Here we predict the neutron skin of selected light- and medium-mass nuclei using coupled-cluster theory and the auxiliary field diffusion Monte Carlo method with two- and three-nucleon forces from chiral effective field theory. We find a linear correlation between the neutron skin and the isospin asymmetry in agreement with the liquid-drop model and compare with data. We also extract the linear relationship that describes the difference between neutron and proton radii of mirror nuclei and quantify the effect of charge symmetry breaking terms in the nuclear Hamiltonian. Our results for the mirror-difference charge radii and binding energies per nucleon agree with existing data.
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Affiliation(s)
- S J Novario
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - D Lonardoni
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S Gandolfi
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - G Hagen
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
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Fujimoto Y, Fukushima K, McLerran LD, Praszałowicz M. Trace Anomaly as Signature of Conformality in Neutron Stars. PHYSICAL REVIEW LETTERS 2022; 129:252702. [PMID: 36608254 DOI: 10.1103/physrevlett.129.252702] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 11/01/2022] [Accepted: 11/14/2022] [Indexed: 06/17/2023]
Abstract
We discuss an interpretation that a peak in the sound velocity in neutron star matter, as suggested by the observational data, signifies strongly coupled conformal matter. The normalized trace anomaly is a dimensionless measure of conformality leading to the derivative and the nonderivative contributions to the sound velocity. We find that the peak in the sound velocity is attributed to the derivative contribution from the trace anomaly that steeply approaches the conformal limit. Smooth continuity to the behavior of high-density QCD implies that the matter part of the trace anomaly may be positive definite. We discuss a possible implication of the positivity condition of the trace anomaly on the M-R relation of the neutron stars.
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Affiliation(s)
- Yuki Fujimoto
- Institute for Nuclear Theory, University of Washington, Box 351550, Seattle, Washington 98195, USA
| | - Kenji Fukushima
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Larry D McLerran
- Institute for Nuclear Theory, University of Washington, Box 351550, Seattle, Washington 98195, USA
| | - Michał Praszałowicz
- Institute for Nuclear Theory, University of Washington, Box 351550, Seattle, Washington 98195, USA
- Institute of Theoretical Physics, Jagiellonian University, S. Łojasiewicza 11, 30-348 Kraków, Poland
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Biswas B, Datta S. Constraining neutron star properties with a new equation of state insensitive approach. Int J Clin Exp Med 2022. [DOI: 10.1103/physrevd.106.043012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Komoltsev O, Kurkela A. How Perturbative QCD Constrains the Equation of State at Neutron-Star Densities. PHYSICAL REVIEW LETTERS 2022; 128:202701. [PMID: 35657894 DOI: 10.1103/physrevlett.128.202701] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 03/14/2022] [Accepted: 04/25/2022] [Indexed: 06/15/2023]
Abstract
We demonstrate in a general and analytic way how high-density information about the equation of state (EOS) of strongly interacting matter obtained using perturbative quantum chromodynamics constrains the same EOS at densities reachable in physical neutron stars. Our approach is based on utilizing the full information of the thermodynamic potentials at the high-density limit together with thermodynamic stability and causality. This requires considering the pressure as a function of chemical potential p(μ) instead of the commonly used pressure as a function of energy density p(ε). The results can be used to propagate the perturbative quantum chromodynamics calculations reliable around 40n_{s} to lower densities in the most conservative way possible. We constrain the EOS starting from only a few times the nuclear saturation density n≳2.2n_{s}, and at n=5n_{s} we exclude at least 65% of otherwise allowed area in the ε-p plane. This provides information complementary to astrophysical observations that should be taken into account in any complete statistical inference study of the EOS. These purely theoretical results are independent of astrophysical neutron-star input, and hence, they can also be used to test theories of modified gravity and beyond the standard model physics in neutron stars.
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Affiliation(s)
- Oleg Komoltsev
- Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway
| | - Aleksi Kurkela
- Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway
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Chatziioannou K. Uncertainty limits on neutron star radius measurements with gravitational waves. Int J Clin Exp Med 2022. [DOI: 10.1103/physrevd.105.084021] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Pacilio C, Maselli A, Fasano M, Pani P. Ranking Love Numbers for the Neutron Star Equation of State: The Need for Third-Generation Detectors. PHYSICAL REVIEW LETTERS 2022; 128:101101. [PMID: 35333071 DOI: 10.1103/physrevlett.128.101101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 01/22/2022] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
Gravitational-wave measurements of the tidal deformability in neutron-star binary coalescences can be used to infer the still unknown equation of state (EOS) of dense matter above the nuclear saturation density. By employing a Bayesian-ranking test, we quantify the ability of current and future gravitational-wave observations to discriminate among families of nuclear-physics based EOS which differ in particle content and ab initio microscopic calculations. While the constraining power of GW170817 is limited, we show that even twenty coalescences detected by LIGO-Virgo at design sensitivity are not enough to discriminate between EOS with similar softness but distinct microphysics. However, just a single detection with a third-generation detector such as the Einstein Telescope or Cosmic Explorer will rule out several families of EOS with very strong statistical significance and can discriminate among models which feature similar softness, hence, constraining the properties of nuclear matter to unprecedented levels.
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Affiliation(s)
- Costantino Pacilio
- Dipartimento di Fisica, "Sapienza" Università di Roma, Piazzale Aldo Moro 5, 00185 Roma, Italy
- INFN, Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy
| | - Andrea Maselli
- Gran Sasso Science Institute (GSSI), I-67100 L'Aquila, Italy
- INFN, Laboratori Nazionali del Gran Sasso, I-67100 Assergi, Italy
| | - Margherita Fasano
- Dipartimento di Fisica, "Sapienza" Università di Roma, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Paolo Pani
- Dipartimento di Fisica, "Sapienza" Università di Roma, Piazzale Aldo Moro 5, 00185 Roma, Italy
- INFN, Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy
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Nuclear Physics and Astrophysics Constraints on the High Density Matter Equation of State. UNIVERSE 2021. [DOI: 10.3390/universe7080257] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
(1) This review has been written in memory of Steven Moszkowski who unexpectedly passed away in December 2020. It has been inspired by our many years of discussions. Steven’s enthusiasm, drive and determination to understand atomic nuclei in simple terms of basic laws of physics was infectious. He sought the fundamental origin of nuclear forces in free space, and their saturation and modification in nuclear medium. His untimely departure left our job unfinished but his legacy lives on. (2) Focusing on the nuclear force acting in nuclear matter of astrophysical interest and its equation of state (EoS), we take several typical snapshots of evolution of the theory of nuclear forces. We start from original ideas in the 1930s moving through to its overwhelming diversity today. The development is supported by modern observational and terrestrial data and their inference in the multimessenger era, as well as by novel mathematical techniques and computer power. (3) We find that, despite the admirable effort both in theory and measurement, we are facing multiple models dependent on a large number of variable correlated parameters which cannot be constrained by data, which are not yet accurate, nor sensitive enough, to identify the theory closest to reality. The role of microphysics in the theories is severely limited or neglected, mostly deemed to be too difficult to tackle. (4) Taking the EoS of high-density matter as an example, we propose to develop models, based, as much as currently possible, on the microphysics of the nuclear force, with a minimal set of parameters, chosen under clear physical guidance. Still somewhat phenomenological, such models could pave the way to realistic predictions, not tracing the measurement, but leading it.
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