Novel phases in strongly coupled four-fermion theories

Journal Article · 06 August 2017 · Physical Review. D.

DOI: https://doi.org/10.1103/physrevd.96.034506 · OSTI ID:1536350

Catterall, Simon ^[1]; Schaich, David ^[2]

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1. Syracuse University, NY (United States); DOE/OSTI
2. Syracuse University, NY (United States); University of Bern (Switzerland)

Here, we study a lattice model comprising four massless reduced staggered fermions in four dimensions coupled through an SU(4)-invariant four-fermion interaction. We present both theoretical arguments and numerical evidence that no bilinear fermion condensates are present for any value of the four-fermi coupling, in contrast to earlier studies of Higgs{Yukawa models with different exact lattice symmetries. At strong coupling we observe the formation of a four-fermion condensate and a mass gap in spite of the absence of bilinear condensates. Unlike those previously studied systems we do not find a ferromagnetic phase separating this strong-coupling phase from the massless weak-coupling phase. Instead we observe long-range correlations in a narrow region of the coupling, still with vanishing bilinear condensates. While our numerical results come from relatively small lattice volumes that call for caution in drawing conclusions, if this novel phase structure is verified by future investigations employing larger volumes it may offer the possibility for new continuum limits for strongly interacting fermions in four dimensions.

• Research Organization: Syracuse University, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: SC0009998
• OSTI ID: 1536350
• Alternate ID(s): OSTI ID: 1374217
• Journal Information: Physical Review. D., Journal Name: Physical Review. D. Journal Issue: 3 Vol. 96; ISSN 2470-0010
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English