40,282 research outputs found
Low-Energy Lorentz Invariance in Lifshitz Nonlinear Sigma Models
This work is dedicated to the study of both large- and perturbative
quantum behaviors of Lifshitz nonlinear sigma models with dynamical critical
exponent in 2+1 dimensions. We discuss renormalization and
renormalization group aspects with emphasis on the possibility of emergence of
Lorentz invariance at low energies. Contrarily to the perturbative expansion,
where in general the Lorentz symmetry restoration is delicate and may depend on
stringent fine-tuning, our results provide a more favorable scenario in the
large- framework. We also consider supersymmetric extension in this
nonrelativistic situation.Comment: 28 pages, 4 figures, minor clarifications, typos corrected, published
versio
Lorentz Invariance in Shape Dynamics
Shape dynamics is a reframing of canonical general relativity in which time
reparametrization invariance is "traded" for a local conformal invariance. We
explore the emergence of Lorentz invariance in this model in three contexts: as
a maximal symmetry, an asymptotic symmetry, and a local invariance.Comment: v2: discussion of light cone structure added; minor typos fixed; 14
page
On Ward Identities in Lifshitz-like Field Theories
In this work, we develop a normal product algorithm suitable to the study of
anisotropic field theories in flat space, apply it to construct the symmetries
generators and describe how their possible anomalies may be found. In
particular, we discuss the dilatation anomaly in a scalar model with critical
exponent z=2 in six spatial dimensions.Comment: Clarifications adde
Mean Field Limits for Interacting Diffusions in a Two-Scale Potential
In this paper we study the combined mean field and homogenization limits for
a system of weakly interacting diffusions moving in a two-scale, locally
periodic confining potential, of the form considered
in~\cite{DuncanPavliotis2016}. We show that, although the mean field and
homogenization limits commute for finite times, they do not, in general,
commute in the long time limit. In particular, the bifurcation diagrams for the
stationary states can be different depending on the order with which we take
the two limits. Furthermore, we construct the bifurcation diagram for the
stationary McKean-Vlasov equation in a two-scale potential, before passing to
the homogenization limit, and we analyze the effect of the multiple local
minima in the confining potential on the number and the stability of stationary
solutions
Beliefs and actions in the trust game: creating instrumental variables to estimate the causal effect
In many economic contexts, an elusive variable of interest is the agent's expectation about relevant events, e.g. about other agents' behavior. Recent experimental studies as well as surveys have asked participants to state their beliefs explicitly, but little is known about the causal relation between beliefs and other behavioral variables. This paper discusses the possibility of creating exogenous instrumental variables for belief statements, by shifting the probabilities of the relevant events. We conduct trust game experiments where the amount sent back by
the second player (trustee) is exogenously varied by a random process, in a way that informs only the �first player (trustor) about the realized variation. The procedure
allows detecting causal links from beliefs to actions under plausible assumptions.
The IV estimates indicate a signi�ficant causal effect, comparable to the connection
between beliefs and actions that is suggested by OLS analyses
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