194 research outputs found
Spectral sum rules for confining large-N theories
We consider asymptotically-free four-dimensional large- gauge theories
with massive fermionic and bosonic adjoint matter fields, compactified on
squashed three-spheres, and examine their regularized large- confined-phase
spectral sums. The analysis is done in the limit of vanishing 't Hooft
coupling, which is justified by taking the size of the compactification
manifold to be small compared to the inverse strong scale . Our
results motivate us to conjecture some universal spectral sum rules for these
large gauge theories.Comment: 25 pages, 2 figures. v2: fixed typos, added references, and some
minor improvements to discussio
Bose-Fermi Degeneracies in Large Adjoint QCD
We analyze the large limit of adjoint QCD, an gauge theory with
flavors of massless adjoint Majorana fermions, compactified on . We focus on the weakly-coupled confining small- regime. If
the fermions are given periodic boundary conditions on , we show that
there are large cancellations between bosonic and fermionic contributions to
the twisted partition function. These cancellations follow a pattern previously
seen in the context of misaligned supersymmetry, and lead to the absence of
Hagedorn instabilities for any size , even though the bosonic and
fermionic densities of states both have Hagedorn growth. Adjoint QCD stays in
the confining phase for any , explaining how it is able to enjoy
large volume independence for any . The large boson-fermion
cancellations take place in a setting where adjoint QCD is manifestly
non-supersymmetric at any finite , and are consistent with the recent
conjecture that adjoint QCD has emergent fermionic symmetries in the large
limit.Comment: 35 pages, 5 figures. v3: further minor correction
Modularity and 4D-2D spectral equivalences for large-N gauge theories with adjoint matter
In recent work, we demonstrated that the confined-phase spectrum of
non-supersymmetric pure Yang-Mills theory coincides with the spectrum of the
chiral sector of a two-dimensional conformal field theory in the large-
limit. This was done within the tractable setting in which the gauge theory is
compactified on a three-sphere whose radius is small compared to the strong
length scale. In this paper, we generalize these observations by demonstrating
that similar results continue to hold even when massless adjoint matter fields
are introduced. These results hold for both thermal and -twisted
partition functions, and collectively suggest that the spectra of large-
confining gauge theories are organized by the symmetries of two-dimensional
conformal field theories.Comment: 51 pages, LaTeX, 3 figure
Casimir energy of confining large gauge theories
Four-dimensional asymptotically-free large gauge theories compactified on
have a weakly-coupled confining regime when is
small compared to the strong scale. We compute the vacuum energy of a variety
of confining large non-supersymmetric gauge theories in this calculable
regime, where the vacuum energy can be thought of as the Casimir energy.
The renormalized vacuum energy turns out to vanish in all of the
large gauge theories we have examined, confirming a striking prediction of
temperature-reflection symmetry.Comment: 4 pages, 1 figure. v2: added clarifications and typo corrections,
conclusions unchange
Tests of Universality of Baryon Form Factors in Holographic QCD
We describe a new exact relation for large QCD for the long-distance
behavior of baryon form factors in the chiral limit, satisfied by all 4D
semi-classical chiral soliton models. We use this relation to test the
consistency of the structure of two different holographic models of baryons.Comment: 4 pages. Talk presented by MN at Light Cone 2009: Relativistic
Hadronic and Particle Physics, 8-13 Jul 2009, Sao Jose dos Campos, Brazi
Large Nc Equivalence and Baryons
In the large Nc limit, gauge theories with different gauge groups and matter
content sometimes turn out to be `large Nc equivalent', in the sense of having
a set of coincident correlation functions. Large Nc equivalence has mainly been
explored in the glueball and meson sectors. However, a recent proposal to dodge
the fermion sign problem of QCD with a quark-number chemical potential using
large Nc equivalence motivates investigating the applicability of large Nc
equivalence to correlation functions involving baryon operators. Here we
present evidence that large Nc equivalence extends to the baryon sector, under
the same type of symmetry-realization assumptions as in the meson sector, by
adapting the classic Witten analysis of large Nc baryons.Comment: 12 pages, 13 figures, v2: minor clarifications to match version
published in PRD, v3: typo in fig.5 correcte
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