BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Snir Gazit (Hebrew University) DTSTART:20220519T081500Z DTEND:20220519T091500Z DTSTAMP:20260423T023941Z UID:NMTP2022/14 DESCRIPTION:Title: Unconventional criticality and Fermi-surface reconstruction without symm etry breaking in a simple lattice model of gauge and matter fields.\nb y Snir Gazit (Hebrew University) as part of Numerical Methods in Theoretic al Physics\n\n\nAbstract\nGauge theories play a central role in the theore tical description of unconventional phases of matter that go beyond the st andard paradigms of quantum statistical mechanics. While in high-energy ph ysics\, gauge fields correspond to fundamental particles\, in condensed ma tter theory they are typically emergent and are invoked as an effective de scription of the low-energy degrees of freedom. Notable examples include s pin-liquids\, doped Mott insulators\, and the fractional Hall effect\, amo ng others. In my talk\, I will present a sign-problem free quantum Monte C arlo study of a lattice model hosting 'orthogonal' fermions coupled to an Ising-Higgs gauge theory. Our model provides a simple yet highly non-trivi al example of electron fractionalization\, which\, crucially\, remains num erically tractable. We uncover a particularly rich phase diagram arising f rom strong correlations between gauge and matter fields. In particular\, w e find that in the background of pi-flux lattice an orthogonal semi-metal (OSM) forms with gapless Dirac fermion excitations. With the tuning of par ameters\, the OSM undergoes a confinement transition\, in which symmetry b reaking and confinement are coincident. We construct a field-theoretical d escription of the transition involving condensation of a matrix Higgs fiel d. The critical theory is predicted to sustain emergent and enlarged loca l (gauge) and global symmetries. We provide numerical evidence supporting this prediction. We also find that the physical (gauge-neutral) spectral function in the OSM phase comprises four fermion pockets\, which smoothly evolve to a 'large' Fermi surface upon approach to a Fermi liquid phase. The reconstruction of the Fermi surface does not involve any form of trans lational symmetry breaking\, in violation of the Luttinger sum rule.\n LOCATION:https://researchseminars.org/talk/NMTP2022/14/ END:VEVENT END:VCALENDAR