647 research outputs found
Strings in plane wave backgrounds
I review aspects of string theory on plane wave backgrounds emphasising the
connection to gauge theory given by the BMN correspondence. Topics covered
include the Penrose limit and its role in deriving the BMN duality from
AdS/CFT, light-cone string field theory in the maximally supersymmetric plane
wave and extensions of the correspondence to less supersymmetric backgrounds.Comment: 85 pages, based on PhD thesis, Humboldt University, Berlin; v2: added
reference
PP-Wave Light-Cone Superstring Field Theory
We construct the cubic interaction vertex and dynamically generated
supercharges in light-cone superstring field theory in the pp-wave background.
We show that these satisfy the pp-wave superalgebra at first order in string
coupling. The cubic interaction vertex and dynamical supercharges presented
here differ from the expressions previously given in the literature. Using this
vertex we compute various string theory three-point functions and comment on
their relation to gauge theory in the BMN limit.Comment: 32 pages, 1 figure; v2: typos corrected, reference adde
On the Uniqueness of Plane-wave String Field Theory
We prove that the two interaction Hamiltonians of light-cone closed
superstring field theory in the plane-wave background present in the literature
are identical.Comment: 15 pages late
Model-Based Calibration of Filter Imperfections in the Random Demodulator for Compressive Sensing
The random demodulator is a recent compressive sensing architecture providing
efficient sub-Nyquist sampling of sparse band-limited signals. The compressive
sensing paradigm requires an accurate model of the analog front-end to enable
correct signal reconstruction in the digital domain. In practice, hardware
devices such as filters deviate from their desired design behavior due to
component variations. Existing reconstruction algorithms are sensitive to such
deviations, which fall into the more general category of measurement matrix
perturbations. This paper proposes a model-based technique that aims to
calibrate filter model mismatches to facilitate improved signal reconstruction
quality. The mismatch is considered to be an additive error in the discretized
impulse response. We identify the error by sampling a known calibrating signal,
enabling least-squares estimation of the impulse response error. The error
estimate and the known system model are used to calibrate the measurement
matrix. Numerical analysis demonstrates the effectiveness of the calibration
method even for highly deviating low-pass filter responses. The proposed method
performance is also compared to a state of the art method based on discrete
Fourier transform trigonometric interpolation.Comment: 10 pages, 8 figures, submitted to IEEE Transactions on Signal
Processin
Resolving the Holography in the Plane-Wave Limit of AdS/CFT Correspondence
The issue of holographic mapping between bulk and boundary in the plane-wave
limit of AdS/SYM correspondence is reexamined from the viewpoint of correlation
functions. We first study the limit of large angular momentum for the so-called
GKP-W relation in supergeravity approximation, connecting directly the
effective action in the bulk and the generating functional of correlation
functions on the boundary. The spacetime tunneling picture which has been
proposed in our previous works naturally emerges. This gives not only a
justification of our previous proposal, with some important refinements, on the
mapping between bulk effective interaction and the CFT coefficients on the
boundary in the plane-wave limit, but also implies various insights on the
interpretation of holography in the plane-wave limit. Based on this result, we
construct a new `holographic' string field theory. We confirm for several
nontrivial examples that this gives the CFT coefficients derived by
perturbation theory on the gauge-theory side.
Our results are useful for understanding how apparently different duality
maps proposed from different standpoints are consistent with each other and
with our definite spacetime picture for the AdS holography in the plane-wave
limit.Comment: corrected typos, 57 page
Parent Knowledge Regarding the Relationship Between Literacy and Language Development
Countless research articles support the connection between literacy and language development. This project explores the knowledge parents have about this connection. The paper first summarizes key findings and provides background information about the relationship between literacy and language development. Then, it discusses the results of a survey performed by the researcher. The first section of the survey collected demographic information and the second section contained 16 statements about the relationship between literacy and language development. Survey participants indicated the extent to which they agreed or disagreed with each statement, based on their previous knowledge.
Three main questions were addressed in addition to the overall picture of parent knowledge about literacy and language development:1. Do parents who have completed a higher level of education have more knowledge on this topic? 2. Do parents with an educational background in child development or childhood education have more knowledge on this topic than parents who do not? 3. Do parents with more than one child have more knowledge on this topic than parents with one child?
Results from this current survey indicated that neither level of education, type of educational background, nor the number of children significantly increased the level of knowledge of surveyed participants regarding the relationship between literacy and language development
Strings in plane wave backgrounds
I review aspects of string theory on plane wave backgrounds emphasising the connection to gauge theory given by the BMN correspondence. Topics covered include the Penrose limit and its role in deriving the BMN duality from AdS/CFT, light-cone string field theory in the maximally supersymmetric plane wave and extensions of the correspondence to less supersymmetric backgrounds
K–12 Teacher Reflective Practice in (Pandemic) Context
The author argues for a clear definition of teacher reflective practice that synthesizes newer theoretical perspectives. Social context and teacher practice are discussed to build a definitive benchmark that seems useful to support a more collaborative approach to teacher reflective practice today, including in the context of the pandemic
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