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Nuclear Theory·nucl-th

Friday·June 27, 2025

5 papers—3 primary·2 cross-listed

All5Primary3Cross-lists2
  1. 01

    On the local thermodynamic relations in relativistic spin hydrodynamics

    Francesco Becattini🇮🇹 · Rajeev Singh🇷🇴

    We demonstrate, by providing two specific examples, that the local differential thermodynamic relations used as educated guesses in relativistic hydrodynamics with spin, do not hold even at global thermodynamic equilibrium. We show, by using a rigorous quantum statistical method, that for massless free fermions and massive free fermions with rotation and acceleration at global thermodynamic equilibrium, the derivative of the pressure function with respect to the spin potential differs from the spin density and acquires a correction of the same order. Such correction cannot be eliminated by any redefinition of the entropy current, a so-called entropy-gauge transformation. Therefore, for an accurate determination of the constitutive relations in relativistic spin hydrodynamics, the traditional method of assuming differential thermodynamic relations is not appropriate.

    nucl-thhep-thEPJC(2025)·19 citations
  2. 02

    Relativistic spin hydrodynamics with antisymmetric spin tensors and an extension of the Bargmann-Michel-Telegdi equation

    Shuo Fang🇨🇳 · Kenji Fukushima🇯🇵 · Shi Pu🇨🇳 · Dong-Lin Wang🇨🇳

    We derive a formulation of relativistic spin hydrodynamics with totally antisymmetric spin tensors that satisfy the Frenkel-Mathisson-Pirani condition. In our proposed spin hydrodynamics, the second law of thermodynamics is fulfilled by the spin-induced corrections in the heat flow, the viscous tensor, and the antisymmetric part of the energy-momentum tensor. These corrections are interpreted as the inverse spin Hall effect and the anomalous Hall effect in the nonrelativistic limit. We show that our evolution equation for the spin density is interpreted as an extension of the Bargmann-Michel-Telegdi equation known in relativistic many-body systems, including the Thomas precession term, the spin-rotation term, and new coupling terms between spin and hydrodynamic variables.

    nucl-thhep-phhep-thPRL(2026)·13 citations
  3. 03

    Speed of sound of QCD matter at chiral crossover

    Oleksii Ivanytskyi🇵🇱 · David Blaschke🇵🇱 · Gerd Röpke🇩🇪

    Based on a generalized Beth-Uhlenbeck approach to thermodynamics of QCD motivated by cluster decomposition we present a unified equation of state of hot strongly interacting matter and analyze its properties in a wide range of temperatures. The hadrons are treated as color singlet multiquark clusters in medium with a background gluon field in the Polyakov gauge. The confining aspect of QCD is accounted for by the Polyakov loop mechanism and by a large vacuum quark mass motivated by a confining density functional approach. We demonstrate that an abrupt switching between hadronic and partonic degrees of freedom, which is one of striking manifestations of dynamical restoration of chiral symmetry, is accompanied by a smooth behavior of entropy density at chiral crossover. Individual contributions of different components of strongly interacting matter to its speed of sound are analyzed for the first time. It is shown that restoration of chiral symmetry drives speed of sound of hadron gas to negative values, manifesting its mechanical instability and being in a strike disagreements with the lattice QCD data. Accounting for the partonic excitations naturally resolves this contradiction.

    nucl-thhep-phJ.Subatomic Part.Cosmol.(2025)·0 citations
  4. 04

    Iterative Harrow-Hassidim-Lloyd quantum algorithm for solving resonances with eigenvector continuation

    Hantao Zhang🇨🇳 · Dong Bai🇨🇳 · Zhongzhou Ren🇨🇳

    We propose a novel quantum algorithm for solving nuclear resonances, which is based on the iterative Harrow-Hassidim-Lloyd algorithm and eigenvector continuation with complex scaling. To validate this approach, we compute the resonant states of system and achieve results in good agreement with traditional methods. Our study offers a new perspective on calculating eigenvalues of non-Hermitian operators and lays some groundwork for further exploration of nuclear resonances using quantum computing.

    ↳ quant-phnucl-thPLB(2026)·3 citations
  5. 05

    Proto-neutron Stars with Dark Matter Admixture: A Single-Fluid Approach

    Adamu Issifu🇧🇷 · Débora P. Menezes🇧🇷 · Tobias Frederico🇧🇷

    This work investigates the impact of dark matter (DM) on the microscopic and macroscopic properties of proto-neutron stars (PNSs). We employ a single-fluid framework in which DM interacts with ordinary matter (OM) via the Higgs portal and remains in thermal equilibrium through non-gravitational interactions. Using a quasi-static approximation, we analyze the evolution of PNSs during the Kelvin-Helmholtz phase by varying the DM mass while keeping the entropy per baryon and lepton fraction fixed. Our results show that DM absorbs thermal energy from the stellar medium without efficient re-emission, thereby altering neutrino emission and affecting the star's thermal evolution history. Furthermore, neutrinos contribute significantly to pressure support in the PNS phase, inhibiting DM mass accretion during neutrino-trapped stages. Based on the requirement to satisfy the observed neutron star mass constraint and to maintain consistency with supernova remnant data, we suggest an upper limit of for the DM mass that can accrete in evolving PNSs, within the model framework. In contrast, we established that cold neutron stars (NSs) can support higher DM masses without compromising equilibrium stability, owing to increased central density, enhanced gravitational binding energy, and reduced thermal pressure.

    ↳ astro-ph.HEnucl-thPhys.Dark Univ.(2025)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE