Article
Astronomy & Astrophysics
Anil Kumar, Vivek Baruah Thapa, Monika Sinha
Summary: In this study, we investigate the properties of stars participating in double compact star merger events, considering an interacting model of stable strange quark matter. By modeling the matter and making it compatible with recent astrophysical observations, including compact star mass-radius and gravitational wave events, we find a new upper bound on the tidal deformability of a 1.4 M-circle dot strange star.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
H. C. Das, Ankit Kumar, S. K. Patra
Summary: The study analyzes the observational data of GW190814 to put constraints on its secondary component. Using relativistic mean-field models, the researchers calculate the mass-radius profile and tidal deformability of the compact object, treating it as a massive neutron star with dark matter particles. It is observed that the predicted properties are consistent with the observational data, suggesting the possibility of a dark matter admixed neutron star if the nuclear equation of state is sufficiently stiff.
Article
Multidisciplinary Sciences
Sabrina Huth, Peter T. H. Pang, Ingo Tews, Tim Dietrich, Arnaud Le Fevre, Achim Schwenk, Wolfgang Trautmann, Kshitij Agarwal, Mattia Bulla, Michael W. Coughlin, Chris Van den Broeck
Summary: Studying dense matter is crucial for understanding high-energy astrophysical phenomena, and data from heavy-ion collision experiments provide valuable insights in addition to astrophysical observations. By combining data from various sources, including heavy-ion collisions and microscopic nuclear theory calculations, researchers found significant improvements in their understanding of dense matter and its consistency with observations.
Article
Astronomy & Astrophysics
Billy K. K. Lee, Ming-chung Chu, Lap-Ming Lin
Summary: The investigation explores the possibility of a 2.6 M(circledot) compact object in the gravitational wave event GW190814 being a compact star admixed with bosonic dark matter. Constraints on the mass, radius, and stability of the object suggest that the dark matter may be composed of QCD axions, with their particle mass range potentially overlapping with constraints from black hole superradiance processes.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Hristijan Kochankovski, Angels Ramos, Laura Tolos
Summary: The FSU2H equation-of-state model is extended to finite temperature and it is found that temperature has a stronger effect on thermodynamical observables and the composition of neutron star cores when considering hyperonic degrees of freedom. The widely used Gamma law is not appropriate to reproduce the true thermal effects, especially when hyperons become abundant in the neutron star core. Simple parametrizations of the thermal index for nucleonic and hyperonic beta-stable neutrino-free matter are provided to make finite temperature equations of state easily accessible.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Ankit Kumar, H. C. Das, S. K. Patra
Summary: Motivated by theoretical studies on efficient dark matter capture by neutron stars, this research explores the indirect effects of captured dark matter on the cooling mechanism of a neutron star. The study shows that varying dark matter momentum greatly modifies neutrino emissivity and investigates specific heat and thermal conductivity of a dark matter admixed star to explore cooling wave propagation within the star.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
P. Mafa Takisa, S. D. Maharaj, M. L. Lekala
Summary: This work models compact stars using an equation of state of dark matter with admixed matter, exploring physical features and mass limits, and showing the influence of the nonlinear term on matter distribution. In particular, the maximum stellar mass of PSRJ0030+0451 is found for the admixed matter distribution.
ASTROPHYSICS AND SPACE SCIENCE
(2021)
Article
Astronomy & Astrophysics
Nathan Rutherford, Geert Raaijmakers, Chanda Prescod-Weinstein, Anna Watts
Summary: Neutron stars can accumulate asymmetric dark matter (ADM) in their interiors, affecting their measurable properties and making them important targets in the search for ADM. Bayesian inference is used in this study to explore neutron star mass-radius measurements from x-ray telescopes, both current and future, in order to constrain the parameters of bosonic ADM. The results show that the current uncertainties in the baryonic equation of state prevent constraints on the ADM parameter space. However, the inclusion of bosonic ADM in neutron star cores relaxes constraints on the baryonic equation of state space.
Article
Physics, Particles & Fields
S. A. Mardan, I Noureen, A. Khalid
Summary: The study successfully constructed a relativistic core-envelope model, matching core, envelope, and the Reissner Nordstrom exterior regions, discussing various physical parameters in compact stars while maintaining non-singularity and continuity. The impact of a charged compact object together with the core-envelope model on mass, radius, and compactification factor was described through graphical representation in both core and envelope regions. The stability of the model was analyzed using Tolman-Oppenheimer-Volkoff equations and radial sound speed.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Long-Qi Shao, Yong-Liang Ma
Summary: In this study, dense compact star matter is investigated using the skyrmion crystal approach with a chiral effective theory that includes scalar and vector mesons as well as pions. The results show constraints on the anomalous dimension of the gluon field and the significance of scale symmetry breaking. The conformal limits on the speed of sound and the polytropic index are satisfied, but they cannot be used to determine the onset of quark matter.
Article
Astronomy & Astrophysics
Omar Benhar, Alessandro Lovato, Giovanni Camelio
Summary: The interpretation of data from multimessenger astrophysical observations can provide unprecedented access to neutron star properties. To achieve this, novel and accurate theoretical models are needed to describe dense matter. Studying thermal effects, including transport coefficients and neutrino mean free path in the nuclear medium, is crucial in this context.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Silvia Traversi, Prasanta Char, Giuseppe Pagliara, Alessandro Drago
Summary: This study explores the relationship between the existence of massive compact stars and their speed of sound, and finds that if these stars are strange quark stars, which are composed entirely of quarks, the speed of sound can be below the conformal limit. By using Bayesian analysis and astrophysical data, the study reveals that the posterior distribution of the squared speed of sound is peaked around 0.3, and the maximum mass of the most probable equation of state is approximately 2.13 times the mass of the Sun.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Cheng-Jun Xia, Jian-Feng Xu, Guang-Xiong Peng, Ren-Xin Xu
Summary: The interface effects of quark matter are crucial in determining the properties of compact stars and small nuggets. By introducing a density derivative term and adopting specific parameter sets, it is possible to reproduce the results obtained by solving Dirac equations, with a significant impact of symmetry energy on udQM nuggets.
Article
Quantum Science & Technology
Seungmo Yang, Kyoung-Woong Moon, Changsoo Kim, Duck-Ho Kim, Jeonghun Shin, Jinpyo Hong, Se Kwon Kim, Chanyong Hwang
Summary: This research presents new insights into the precise control of half-skyrmion motion by completely suppressing the skyrmion Hall effect through deformation of skyrmions' internal structure, which is experimentally achieved by an external magnetic field to steer current-driven half-skyrmions in the desired direction. Moreover, it demonstrates the potential of half-skyrmions application beyond skyrmion-based electronics based on their unique advantages.
ADVANCED QUANTUM TECHNOLOGIES
(2021)
Article
Multidisciplinary Sciences
Hariom Jani, Jheng-Cyuan Lin, Jiahao Chen, Jack Harrison, Francesco Maccherozzi, Jonathon Schad, Saurav Prakash, Chang-Beom Eom, A. Ariando, T. Venkatesan, Paolo G. Radaelli
Summary: In the quest for post-CMOS technologies, researchers have shown promising results in experimenting with topologically protected ferromagnetic whirls such as skyrmions and their anti-particles, which can serve as solitonic information carriers. Antiferromagnetic analogues have become the subject of intense focus due to their predicted relativistic dynamics and potential for fast deflection-free motion and size scaling, although experimental demonstration in natural antiferromagnetic systems has yet to be achieved. By utilizing a first-order analogue of the Kibble-Zurek mechanism, a family of topological antiferromagnetic spin textures has been stabilized on an Earth-abundant oxide insulator, showing potential for low-energy antiferromagnetic spintronics at room temperature.