15,844 research outputs found
WdW-patches in AdS and complexity change under conformal transformations II
We study the null-boundaries of Wheeler-de Witt (WdW) patches in three
dimensional Poincare-AdS, when the selected boundary timeslice is an arbitrary
(non-constant) function, presenting some useful analytic statements about them.
Special attention will be given to the piecewise smooth nature of the
null-boundaries, due to the emergence of caustics and null-null joint curves.
This is then applied, in the spirit of our previous paper arXiv:1806.08376, to
the problem of how complexity of the CFT groundstate changes under a small
local conformal transformation according to the action (CA) proposal. In stark
contrast to the volume (CV) proposal, where this change is only proportional to
the second order in the infinitesimal expansion parameter , we show
that in the CA case we obtain terms of order and even
. This has strong implications for the possible
field-theory duals of the CA proposal, ruling out an entire class of them.Comment: 31 pages + appendices, 9 figures v2: minor improvements, matches
published versio
A complexity/fidelity susceptibility g-theorem for AdS/BCFT
We use a recently proposed holographic Kondo model as a well-understood
example of AdS/boundary CFT (BCFT) duality, and show explicitly that in this
model the bulk volume decreases along the RG flow. We then obtain a proof that
this volume loss is indeed a generic feature of AdS/BCFT models of the type
proposed by Takayanagi in 2011. According to recent proposals holographically
relating bulk volume to such quantities as complexity or fidelity
susceptibility in the dual field theory, this suggests the existence of a
complexity or fidelity susceptibility analogue of the Affleck-Ludwig g-theorem,
which famously states the decrease of boundary entropy along the RG flow of a
BCFT. We comment on this possibility.Comment: 24 pages, 4 figures v2: added citations and minor clarification
Two Simple Approaches to Sol-Gel Transition
We represent a theory of polymer gelation as an analogue of liquid-glass
transition in which elastic fields of stress and strain shear components appear
spontaneously as a consequence of the cross-linking of macromolecules. This
circumstance is explained on the basis of obvious combinatoric arguments as
well as a synergetic Lorenz system, where the strain acts as an order
parameter, a conjugate field is reduced to the elastic stress, and the number
of cross-links is a control parameter. Both the combinatoric and synergetic
approaches show that an anomalous slow dependence of the shear modulus on the
number of cross-links is obtained.Comment: 10 pages, LaTe
Rheological Study of Transient Networks with Junctions of Limited Multiplicity II. Sol/Gel Transition and Rheology
Viscoelastic and thermodynamic properties of transient gels formed by
telechelic polymers are studied on the basis of the transient network theory
that takes account of the correlation among polymer chains via network
junctions. The global information of the gel is incorporated into the theory by
introducing the elastically effective chains according to the criterion by
Scanlan and Case. We also consider effects of superbridges whose backbone is
formed by several chains connected in series with several breakable junctions
inside. Near the critical concentration for the sol/gel transition,
superbridges becomes infinitely long along the backbone, thereby leading to the
short relaxation time of the network. It is shown that is
proportional to the concentration deviation near the gelation point.
The plateau modulus increases as the cube of near the
gelation point as a result of the mean-field treatment, and hence the
zero-shear viscosity increases as . The
dynamic shear moduli are well described in terms of the Maxwell model, and it
is shown that the present model can explain the concentration dependence of the
dynamic moduli for aqueous solutions of telechelic poly(ethylene oxide).Comment: 18 pages, 12 figures, 2 table
Bending branes for DCFT in two dimensions
We consider a holographic dual model for defect conformal field theories
(DCFT) in which we include the backreaction of the defect on the dual geometry.
In particular, we consider a dual gravity system in which a two-dimensional
hypersurface with matter fields, the brane, is embedded into a
three-dimensional asymptotically Anti-de Sitter spacetime. Motivated by recent
proposals for holographic duals of boundary conformal field theories (BCFT), we
assume the geometry of the brane to be determined by Israel junction
conditions. We show that these conditions are intimately related to the energy
conditions for the brane matter fields, and explain how these energy conditions
constrain the possible geometries. This has implications for the holographic
entanglement entropy in particular. Moreover, we give exact analytical
solutions for the case where the matter content of the brane is a perfect
fluid, which in a particular case corresponds to a free massless scalar field.
Finally, we describe how our results may be particularly useful for extending a
recent proposal for a holographic Kondo model.Comment: 35 pages + appendices, 12 figures, v2: added references and a
paragraph on negative tension solutions, v3: updated reference
Getting and Keeping Health Coverage for Low-Income Californians: A Guide for Advocates
Western Center's "Getting and Keeping Health Care Coverage for Low-Income Californians: A Guide for Advocates", provides California advocates -- legal services attorneys, enrollment counselors, health care workers, community organizers and others -- with the relevant statutes, regulations, and guidance needed to help their clients access health care coverage. Our hope is that this guide provides those in the field with the necessary support needed to help low-income Californians determine eligibility, and enroll and retain coverage
Development of reclaimed potable water quality criteria
In order to minimize launch requirements necessary to meet the demands of long-term spaceflight, NASA will reuse water reclaimed from various on-board sources including urine, feces, wash water and humidity condensate. Development of reclamation systems requires the promulgation of water quality standards for potable reuse of the reclaimed water. Existing standards for domestic U.S. potable water consumption were developed, but do not consider the peculiar problems associated with the potable reuse of recycled water. An effort was made to: (1) define a protocol by which comprehensive reclaimed water potability/palatability criteria can be established and updated; and (2) continue the effort to characterize the organic content of reclaimed water in the Regenerative Life Support Evaluation
- …