Quark formation and phenomenology in binary neutron-star mergers using V-QCD

Abstract

Using full 3+1 dimensional general-relativistic hydrodynamic simulations of equal- and unequal-mass neutron-star binaries with properties that are consistent with those inferred from the inspiral of GW170817, we perform a detailed study of the quark-formation processes that could take place after merger. We use three equations of state consistent with current pulsar observations derived from a novel finite-temperature framework based on V-QCD, a non-perturbative gauge/gravity model for Quantum Chromodynamics. In this way, we identify three different post-merger stages at which mixed baryonic and quark matter, as well as pure quark matter, are generated. A phase transition triggered collapse already \lesssim 10 ms≲10ms after the merger reveals that the softest version of our equations of state is actually inconsistent with the expected second-long post-merger lifetime of GW170817. Our results underline the impact that gravitational wave observations of binary neutron-star mergers can have in constraining the equation of state of nuclear matter, especially in its most extreme regimes.

Exploring the Phase Diagram of V-QCD with Neutron Star Merger Simulations

“…In addition, we mark contours for the quark fraction Y quark = 0.01, 0.1, 0.5 by dotted, dashed and solid lines, respectively. See [26] for details.…”

“…This proceedings contribution summarises material published in [23,26] and was presented at The XVth Quark confinement and the Hadron spectrum conference. Energy density In this section we briefly summarise the V-QCD framework for the hybrid EOS model used in our merger simulations (for details see [23,27]).…”

“…Shown above is the h 22 + of the strain (left), the power-spectral density of the effective strain (middle), and the spectrogram (right) of the h 22+ of the soft model with (top) and without quark matter (center) as well as the intermediate model (bottom) for q = 0.7 and M chirp = 1.188. See[26] for details.…”

Holographic dense QCD in the Veneziano limit

“…The finite temperature V-QCD EOSs were used in state-of-the-art neutron star merger simulations in [82]. That is, we evolved four dimensional general relativity and hydrodynamics by using the holographic EOS as an input.…”

Magnetic-field Induced Deformation in Hybrid Stars

“…Several new DD-RMF parameter sets such as DD-LZ1 (Wei et al 2020) and DD-MEX (Taninah et al 2020) also produce stiff EoSs. Note that the density-dependent functional DD2 EoS (Typel & Wolter 1999;Typel et al 2010;Banik et al 2014) with excluded volume correction (Typel 2016), which accounts for the finite size of nucleons caused by the repulsive attraction between their internal quarks caused by Pauli blocking effects, is widely used in simulations of, for example, binary NS mergers (Lehner et al 2016;Sekiguchi et al 2016;Radice et al 2018;Tootle et al 2022) and supernovae (Fischer 2021;Jakobus et al 2022).…”