Eur. Phys. J. A (2017) 53: 207
https://doi.org/10.1140/epja/i2017-12398-x

Regular Article - Theoretical Physics

Constructing a neutron star from the lattice in G₂-QCD

University of Graz, Institute of Physics, NAWI Graz, Universitätsplatz 5, 8010, Graz, Austria

^* e-mail: ouraman.hajizadeh@uni-graz.at

Received: 9 March 2017
Accepted: 25 September 2017
Published online: 24 October 2017

Abstract

The inner structure of neutron stars is still an open question. One obstacle is the infamous sign problem of lattice QCD, which bars access to the high-density equation of state. A possibility to make progress and understand the qualitative impact of gauge interactions on the neutron star structure is to study a modified version of QCD without the sign problem. In the modification studied here the gauge group of QCD is replaced by the exceptional Lie group , which keeps neutrons in the spectrum. Using an equation of state from lattice calculations only we determine the mass-radius-relation for a neutron star using the Tolman-Oppenheimer-Volkoff equation. This allows us to understand the challenges and approximations currently necessary to use lattice data for this purpose. We discuss in detail the particular uncertainties and systematic problems of this approach.