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

Impurity Non-Preserving 3-Point Correlators of BMN Operators from PP-Wave Holography II : Fermionic Excitations

The holographic principle in the pp-wave limit proposed in our previous works is further confirmed by studying impurity non-preserving processes which contain a fermionic BMN operator with one scalar and one fermion impurities. We show that the previously proposed duality relation between the matrix elements of the three point interaction Hamiltonian in the holographic string field theory and the OPE coefficients in super Yang-Mills theory holds to the leading order in the large $\mu$ limit. Operator mixing is required to obtain the BMN operator of definite conformal dimension which corresponds to the string state with one scalar and one fermion excitations. The mixing term plays a crucial role for our duality relation to be valid. Our results, combined with those in the previous papers, provide a positive support that our duality relation holds for the general process regardless of the kind of impurities and of whether impurities conserve or not.Comment: 44 pages, 6 figure

Hermione syndrome: Reexamining feminist sidekicks and power in 2000-2010 children’s and young adult fantasy literature

The 2000-2010 decade saw a proliferation of English language fantasy texts for young readers. In the wake of Harry Potter’s success, many other fantasy series followed patterns laid down in Rowling’s text, including writing female characters as Hermione-shaped girls and women. While there are positive aspects to these types of characters, which have been lauded thoroughly in popular culture and the academy, there are also significant drawbacks that have received far less attention. This thesis investigates these Hermione-shaped characters, and the texts from which they come, culturally, narratologically, and epistemologically. The culmination of this research finds that, even against authorial intent, the genre of children’s and young adult fantasy, with its structural narrative patterns as well as ingrained ideological pressures, often creates characters that appear feminist but who often uphold patriarchal power structures

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