BEGIN:VCALENDAR VERSION:2.0 PRODID:-//chikkutakku.com//RDFCal 1.0//EN X-WR-CALDESC:GoogleカレンダーやiCalendar形式情報を共有シェ アしましょう。近所のイベントから全国のイベントま で今日のイベント検索やスケジュールを決めるならち っくたっく X-WR-CALNAME:ちっくたっく X-WR-TIMEZONE:UTC BEGIN:VEVENT SUMMARY:Seminar\, Sho Araki (荒木 匠\, Osaka U.) DTSTART;VALUE=DATE-TIME:20260521T043000Z DTEND;VALUE=DATE-TIME:20260521T053000Z UID:205440172619 DESCRIPTION:Title: The Arf–Brown–Kervaire (ABK) Invariant in Lattice F ermion Systems\n\nAbstract: Topological invariants in fermionic systems pr ovide sharp probes of symmetry and anomaly. In this talk\, we study how to formulate such a topological invariant that is valued in Z_8\, known as t he Arf-Brown-Kervaire (ABK) invariant\, for the lattice fermion systems. T he ABK invariant is a two-dimensional invariant that is encoded in the com plex phase of the Majorana fermion partition function\, and it plays a rol e analogous to topological terms such as the instanton number in 4D Dirac fermion settings. We employ massive Wilson Dirac operators and numerically demonstrate that the ABK invariant emarges on the partition function. To capture the ABK invariant fully\, it is essential to consider various type s of manifold including non-orientable ones such as the real projective pl ane and the Klein bottle. In addition\, manifolds with boundaries are also important for understanding anomaly and anomaly inflow. We discuss how to realize the geometries of these manifolds on the lattice and verify numer ically (and partly analytically) that our formulation reproduces the known values in continuum theory. LOCATION:721 END:VEVENT END:VCALENDAR