20 research outputs found
A matrix CFT at multiple large charges
We investigate matrix models in three dimensions where the global
symmetry acts via the adjoint map. Analyzing their ground state
which is homogeneous in space and can carry either a unique or multiple fixed
charges, we show the existence of at least two distinct fixed points of the
renormalization group (RG) flow. In particular, the one type of those fixed
points manifests itself via tractable deviations in the large-charge expansion
from the known predictions in the literature. We demonstrate most of the novel
features using mainly the example of the matrix theory to
compute the anomalous dimension of the lowest scalar operator with large global
charge(s).Comment: 1+36 pages, 2 figures, minor clarifications added, version to be
published in JHE
Matrix models at large charge
We show that the large-charge formalism can be successfully applied to models
that go beyond the vector models discussed so far in the literature. We study
the explicit example of a conformal matrix model in 2+1 space-time
dimensions at fixed charge and calculate the anomalous dimension and fusion
coefficients at leading order in the charge.Comment: 31 pages, 1 figur
An AdS/EFT correspondence at large charge
Considering theories in sectors of large global charge results in a
semiclassical effective field theory (EFT) description for some
strongly-coupled conformal field theories (CFTs) with continuous global
symmetries. Hence, when studying dualities at large charge, we can have control
over the strongly coupled side of the duality and gain perturbative access to
both dual pairs. In this work we discuss the AdS/CFT correspondence in the
regime where both the EFT and gravity descriptions are valid
and stable ( being the central charge). We present the observation that
the ground state energy as a function of the Abelian charge for a simple
EFT in some three-dimensional CFT coincides with the expression for the mass of
an anti-de Sitter-Reissner-Nordstr\"om black hole as a function of its charge.
This observation allows us to introduce a dictionary relating CFT, EFT and
holographic descriptions. We also find agreement for the higher-derivative
corrections on both sides, suggesting a large- expansion on the EFT side.Comment: 23 pages. Matches published version in Nucl.Phys.
Calabi-Yau compactifications of non-supersymmetric heterotic string theory
Phenomenological explorations of heterotic strings have conventionally
focused primarily on the E8xE8 theory. We consider smooth compactifications of
all three ten-dimensional heterotic theories to exhibit the many similarities
between the non-supersymmetric SO(16)xSO(16) theory and the related
supersymmetric E8xE8 and SO(32) theories. In particular, we exploit these
similarities to determine the bosonic and fermionic spectra of Calabi-Yau
compactifications with line bundles of the non-supersymmetric string. We use
elements of four-dimensional supersymmetric effective field theory to
characterize the non-supersymmetric action at leading order and determine the
Green-Schwarz induced axion-couplings. Using these methods we construct a
non-supersymmetric Standard Model(SM)-like theory. In addition, we show that it
is possible to obtain SM-like models from the standard embedding using at least
an order four Wilson line. Finally, we make a proposal of the states that live
on five branes in the SO(16)xSO(16) theory and find under certain assumptions
the surprising result that anomaly factorization only admits at most a single
brane solution.Comment: 1+40 pages LaTeX, 3 figures, 8 tables. v2: Flux quantization
condition for the non-supersymmetric theory correcte
Compensating strong coupling with large charge
We study some (conformal) field theories with global symmetries in the sector
where the value of the global charge is large. We find (as expected) that
the low energy excitations of this sector are described by the general form of
Goldstone's theorem in the non-relativistic regime. We also derive the
unexpected result, first presented in [Hellerman et al. 2015], that the
effective field theory describing such sector of fixed contains effective
couplings , where is the
original coupling. Hence, large charge leads to weak coupling. In the last
section of the paper we present an outline of how to compute anomalous
dimensions of the model in this limit.Comment: 20 pages, 2 figures. Version accepted by JHE
Total Empiricism: Learning from Data
Statistical analysis is an important tool to distinguish systematic from
chance findings. Current statistical analyses rely on distributional
assumptions reflecting the structure of some underlying model, which if not met
lead to problems in the analysis and interpretation of the results. Instead of
trying to fix the model or "correct" the data, we here describe a totally
empirical statistical approach that does not rely on ad hoc distributional
assumptions in order to overcome many problems in contemporary statistics.
Starting from elementary combinatorics, we motivate an information-guided
formalism to quantify knowledge extracted from the given data. Subsequently, we
derive model-agnostic methods to identify patterns that are solely evidenced by
the data based on our prior knowledge. The data-centric character of empiricism
allows for its universal applicability, particularly as sample size grows
larger. In this comprehensive framework, we re-interpret and extend model
distributions, scores and statistical tests used in different schools of
statistics.Comment: Keywords: effective description, large-N, operator formalism,
statistical testing, inference, information divergenc
Infinite number of MSSMs from heterotic line bundles?
We consider heterotic E8xE8 supergravity compactified on smooth Calabi-Yau
manifolds with line bundle gauge backgrounds. Infinite sets of models that
satisfy the Bianchi identities and flux quantization conditions can be
constructed by letting their background flux quanta grow without bound. Even
though we do not have a general proof, we find that all examples are at the
boundary of the theory's validity: the Donaldson-Uhlenbeck-Yau equations, which
can be thought of as vanishing D-term conditions, cannot be satisfied inside
the Kaehler cone unless a growing number of scalar Vacuum Expectation Values
(VEVs) is switched on. As they are charged under various line bundles
simultaneously, the gauge background gets deformed by these VEVs to a
non-Abelian bundle. In general, our physical expectation is that such infinite
sets of models should be impossible, since they never seem to occur in exact
CFT constructions.Comment: LaTeX, 8 pages, 4 tables, some references and comments adde