Precursors, Gauge Invariance, and Quantum Error Correction in AdS/CFT

A puzzling aspect of the AdS/CFT correspondence is that a single bulk operator can be mapped to multiple different boundary operators, or precursors. By improving upon a recent model of Mintun, Polchinski, and Rosenhaus, we demonstrate explicitly how this ambiguity arises in a simple model of the field theory. In particular, we show how gauge invariance in the boundary theory manifests as a freedom in the smearing function used in the bulk-boundary mapping, and explicitly show how this freedom can be used to localize the precursor in different spatial regions. We also show how the ambiguity can be understood in terms of quantum error correction, by appealing to the entanglement present in the CFT. The concordance of these two approaches suggests that gauge invariance and entanglement in the boundary field theory are intimately connected to the reconstruction of local operators in the dual spacetime.Comment: 25 pages, 6 figure

Sub-AdS Scale Locality in AdS3_3/CFT2_2

We investigate sub-AdS scale locality in a weakly coupled toy model of the AdS$_3$/CFT$_2$ correspondence. We find that this simple model has the correct density of states at low and high energies to be dual to Einstein gravity coupled to matter in AdS$_3$. Bulk correlation functions also have the correct behavior at leading order in the large $N$ expansion, but non-local effects emerge at order $1/N$. Our analysis leads to the conjecture that any large $N$ CFT$_2$ that is modular invariant and has the right low-energy density of states is dual to a gravitational theory with sub-AdS scale locality.Comment: 19 page

Science on a Shoestring: Building Nursing Knowledge With Limited Funding

Building the science for nursing practice has never been more important. However, shrunken federal and state research budgets mean that investigators must find alternative sources of financial support and develop projects that are less costly to carry out. New investigators often build beginning programs of research with limited funding. This article provides an overview of some cost-effective research approaches and gives suggestions for finding other sources of funding. Examples of more cost-effective research approaches include adding complementary questions to existing funded research projects; conducting primary analysis of electronic patient records and social media content; conducting secondary analysis of data from completed studies; reviewing and synthesizing previously completed research; implementing community-based participatory research; participating in collaborative research efforts such as inter-campus team research, practice-based research networks (PBRNs), and involving undergraduate and doctoral students in research efforts. Instead of relying on funding from the National Institutes of Health (NIH) and other government agencies, nurse researchers may be able to find support for research from local sources such as businesses, organizations, or clinical agencies. Investigators will increasingly have to rely on these and other creative approaches to fund and implement their research programs if granting agency budgets do not significantly expand

\u3ci\u3eLissodelphis peroni\u3c/i\u3e

Order Cetacea, Suborder Odontoceti, Family Delphinidae. The subfamily Lissodelphinae has been proposed for this genus (Fraser and Purves, 1960), but it has not been universally accepted (Kasuya, 1973). There are two species in the genus: Lissodelphis peronii (southern right whale dolphin) and L. borealis (northern right whale dolphin). Lissodelphis peronii currently contains no subspecies

Geometry of the infalling causal patch

The firewall paradox states that an observer falling into an old black hole must see a violation of unitarity, locality, or the equivalence principle. Motivated by this remarkable conflict, we analyze the causal structure of black hole spacetimes in order to determine whether all the necessary ingredients for the paradox fit within a single observer's causal patch. We particularly focus on the question of whether the interior partner modes of the outgoing Hawking quanta can, in principle, be measured by an infalling observer. Since the relevant modes are spread over the entire sphere, we answer a simple geometrical question: can any observer see an entire sphere behind the horizon? We find that for all static black holes in 3+1 and higher dimensions, with any value of the cosmological constant, no single observer can see both the early Hawking radiation and the interior modes. We present a detailed description of the causal patch geometry of the Schwarzschild black hole in 3+1 dimensions, where an infalling observer comes closest to being able to measure the relevant modes.Comment: 21 pages, 7 figures. Minor edits/reformatting. Consistent with version published in PR

Effects of soil-moisture content on shallow seismic data

This is the publisher's version, also available electronically from "http://library.seg.org".Repeated shallow‐seismic experiments were conducted at a site on days with different near‐surface moisture conditions in unconsolidated material. Experimental field parameters remained constant to ensure comparability of results. Variations in the seismic data are attributed to the changes in soil‐moisture content of the unconsolidated material. Higher amplitudes of reflections and refractions were obtained under wetter near‐surface conditions. An increase in amplitude of 21 dB in the 100–300 Hz frequency range was observed when the moisture content increased from 18% to 36% in the upper 0.15 m (0.5 ft) of the subsurface. In the time‐domain records, highly saturated soil conditions caused large‐amplitude ringy wavelets that interfered with and degraded the appearance of some of the reflection information in the raw field data. This may indicate that an intermediate near‐surface moisture content is most conducive to the recording of high‐quality shallow‐seismic reflection data at this site. This study illustrates the drastic changes that can occur in shallow‐seismic data due to variations in near‐surface moisture conditions. These conditions may need to be considered to optimize the acquisition timing and parameters prior to collection of data