Kirill Shtengel

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Formulating consistent theories describing strongly correlated
metallic topological phases is an outstanding problem in
condensed-matter physics. I will present an explicit construction of a
fractionalized analog of the Weyl semimetal state: the fractional
chiral metal. Our approach is to construct a 4+1D quantum Hall
insulator by stacking 3+1D Weyl semimetals in a magnetic field. In a
strong enough field, the low-energy physics is determined by the
lowest Landau level of each Weyl semimetal, which is highly degenerate
and chiral, motivating us to use a coupled-wire approach. In the
presence of electron-electron interactions a gapped phase emerges; its
electromagnetic response is given in terms of a Chern-Simons field
theory. A boundary of this four dimensional phase remains gapless. The
boundary's response to an external electromagnetic field is determined
by a chiral anomaly with a fractional coefficient. We suggest that
such an anomalous response can be taken as a working definition of a
fractionalized strongly correlated analog of the Weyl semimetal state.

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UC Riverside
Seminar Room 0.03, ETP
Contact: Simon Trebst