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Maria Neuzil

Publications and source records attributed to Maria Neuzil.

6 recordsLinked to original sources

Bosonization versus the Nielsen-Ninomiya theorem

Thanks to bosonization, bosonic lattice models can offer a lattice regularization of chiral fermions. We construct chiral lattice fermion operators in the 2D modified Villain scalar model and evaluate their correlation functions. This microscopic bosonic model has an ultra-local action and an ultra-local symmetry that realizes the fermionic chiral symmetry under bosonization. The reconstructed lattice Dirac operator has no doublers, but is consistent with the Nielsen-Ninomiya theorem because it turns out to be non-local. The non-locality of this derived quantity at finite lattice spacing does not pose any obstructions to gauging the non-anomalous symmetries of the model, which is itself ultra-local.

hep-th

Symmetry theta angles and topological Witten effects

We introduce a large class of $\theta$ angles in quantum field theory that we call symmetry $\theta$ angles. Unlike conventional $\theta$ angles whose definition depends on a choice of a path integral, symmetry $\theta$ angles are intrinsic parameters of a quantum field theory that depend only on its symmetries. A frequent consequence of symmetry $\theta$ angles is a phenomenon we call the topological Witten effect, which is a generalization of the standard Witten effect. Topological Witten effects modify which charged operators are attached to topological operators as a function of $\theta$. Physically, topological Witten effects induce generalized Aharonov-Bohm effects. We show that these new $\theta$ angles and Witten effects can appear in many familiar field theories.

hep-th

Cheshire $\theta$ terms, Aharonov-Bohm effects, and axions

We discuss unusual $\theta$ terms that can appear in field theories that allow global vortices. These `Cheshire $\theta$ terms' induce Aharonov-Bohm effects for some particles that move around vortices. For example, a Cheshire $\theta$ term can appear in QCD coupled to an axion and induces Aharonov-Bohm effects for baryons and leptons moving around axion strings.

hep-th

Beta Functions of 2d Adjoint QCD

We discuss the long-distance physics of 2d adjoint QCD when it is viewed as an effective field theory, and determine the beta functions for its two classically-marginal four-fermi operators. These four-fermion terms preserve the invertible symmetries of the kinetic terms, and they have important implications at long distances if they are generated at short distances. Our results are likely to be important for future numerical lattice Monte Carlo studies of 2d adjoint QCD.

hep-th

1-form symmetry versus large N QCD

We show that large N QCD does not have an emergent $\mathbb{Z}_N$ 1-form symmetry. Our results suggest that a symmetry-based understanding of (approximate) confinement in QCD would require some further generalization of the notion of generalized global symmetries.

hep-th

Universal Deformations

QFTs with local topological operators feature unusual sectors called "universes," which are separated by infinite-tension domain walls. We show that such systems have relevant deformations with exactly-calculable effects. These deformations allow one to dial the vacuum energy densities of the universes. We describe applications of these deformations to confinement in 2d gauge theories, as well as a curious violation of the effective field theory naturalness principle.

hep-th