We investigate the singularity structure of the (-1)F graded partition function in QCD with nf≥1 massive adjoint fermions in the large-N limit. Here, F is fermion number and N is the number of colors. The large N partition function is made reliably calculable by taking space to be a small three-sphere S3. Singularities in the graded partition function are related to phase transitions and to Hagedorn behavior in the (-1)F-graded density of states. We study the flow of the singularities in the complex "inverse temperature" β plane as a function of the quark mass. This analysis is a generalization of the Lee-Yang-Fisher-type analysis for a theory which is always in the thermodynamic limit thanks to the large N limit. We identify two distinct mechanisms for the appearance of physical Hagedorn singularities and center-symmetry changing phase transitions at real positive β, inflow of singularities from the β=0 point, and collisions of complex conjugate pairs of singularities.
Bibliographical notePublisher Copyright:
© 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/" Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP.