(2,0) Superconformal OPEs in D=6, Selection Rules and Non-renormalization Theorems

We analyse the OPE of any two 1/2 BPS operators of (2,0) SCFT$_6$ by constructing all possible three-point functions that they can form with another, in general long operator. Such three-point functions are uniquely determined by superconformal symmetry. Selection rules are derived, which allow us to infer ``non-renormalization theorems'' for an abstract superconformal field theory. The latter is supposedly related to the strong-coupling dynamics of $N_c$ coincident M5 branes, dual, in the large-$N_c$ limit, to the bulk M-theory compactified on AdS$_7 \times$S$_4$. An interpretation of extremal and next-to-extremal correlators in terms of exchange of operators with protected conformal dimension is given.Comment: some details correcte

Stimulated Emission from a single excited atom in a waveguide

We study stimulated emission from an excited two-level atom coupled to a waveguide containing an incident single-photon pulse. We show that the strong photon correlation, as induced by the atom, plays a very important role in stimulated emission. Additionally, the temporal duration of the incident photon pulse is shown to have a marked effect on stimulated emission and atomic lifetime.Comment: 6 pages, 3 figure

Mama’s Got a Brand New Degree: Education and Changing Perceptions of Femininity During the Mexican Revolution (1910-1917)

Bloody struggles, tense political debates, and general unease characterized Mexico in the early twentieth century. Under former president Porfirio Díaz, tensions grew as the lower classes pleaded for labor and land reform, culminating in a violent period of revolution from 1910 to 1917. As with all conflicts of this scale, the Mexican Revolution prompted the challenging of many long standing social conventions, specifically as they pertained to the role of government and the organization of social classes. With the restructuring of society already underway, many activists capitalized on the uncertainty of the era to push against the subjugation of women. Feminist movements were not new to Mexico; however, the revolution presented an opportunity to raise women\u27s stations and make space for them outside of the home. With this campaign to bolster women’s positions in society came critical examinations of the existing gender roles and perceptions of femininity. Class struggles revealed how typical understandings of women’s role in society–specifically remaining confined to the home–derived from upper class customs, and often proved inapplicable or unattainable for those of lower socioeconomic standing. This period also saw immense conflicts between the Mexican state and the Catholic Church on the grounds of political power and land ownership, however the Church provided one of the few opportunities for women to participate in the public sphere. This relationship helped define many aspects of femininity as the revolution approached and became a prominent discussion point in the fight for education as many champions of the anti-clerical movement argued in support of women’s education as a means to decrease their reliance on the institution. Women\u27s suffrage, soldaderas, prostitution, and sex education all played key roles in exposing and morphing how Mexican society conceptualized femininity. The fight for women’s education became a focal point of revolutionary Mexico by embodying the Mexican public’s attempt to integrate changing perceptions of femininity into the emerging modern era as the struggle pushed many women from their previous places in the home into the public sphere

Experiments to investigate particulate materials in reduced gravity fields

Study investigates agglomeration and macroscopic behavior in reduced gravity fields of particles of known properties by measuring and correlating thermal and acoustical properties of particulate materials. Experiment evaluations provide a basis for a particle behavior theory and measure bulk properties of particulate materials in reduced gravity

A common goodness-of-fit framework for neural population models using marked point process time-rescaling

A critical component of any statistical modeling procedure is the ability to assess the goodness-of-fit between a model and observed data. For spike train models of individual neurons, many goodness-of-fit measures rely on the time-rescaling theorem and assess model quality using rescaled spike times. Recently, there has been increasing interest in statistical models that describe the simultaneous spiking activity of neuron populations, either in a single brain region or across brain regions. Classically, such models have used spike sorted data to describe relationships between the identified neurons, but more recently clusterless modeling methods have been used to describe population activity using a single model. Here we develop a generalization of the time-rescaling theorem that enables comprehensive goodness-of-fit analysis for either of these classes of population models. We use the theory of marked point processes to model population spiking activity, and show that under the correct model, each spike can be rescaled individually to generate a uniformly distributed set of events in time and the space of spike marks. After rescaling, multiple well-established goodness-of-fit procedures and statistical tests are available. We demonstrate the application of these methods both to simulated data and real population spiking in rat hippocampus. We have made the MATLAB and Python code used for the analyses in this paper publicly available through our Github repository at https://github.com/Eden-Kramer-Lab/popTRT.This work was supported by grants from the NIH (MH105174, NS094288) and the Simons Foundation (542971). (MH105174 - NIH; NS094288 - NIH; 542971 - Simons Foundation)Published versio

Nonlinear field theories during homogeneous spatial dilation

The effect of a uniform dilation of space on stochastically driven nonlinear field theories is examined. This theoretical question serves as a model problem for examining the properties of nonlinear field theories embedded in expanding Euclidean Friedmann-Lema\^{\i}tre-Robertson-Walker metrics in the context of cosmology, as well as different systems in the disciplines of statistical mechanics and condensed matter physics. Field theories are characterized by the speed at which they propagate correlations within themselves. We show that for linear field theories correlations stop propagating if and only if the speed at which the space dilates is higher than the speed at which correlations propagate. The situation is in general different for nonlinear field theories. In this case correlations might stop propagating even if the velocity at which space dilates is lower than the velocity at which correlations propagate. In particular, these results imply that it is not possible to characterize the dynamics of a nonlinear field theory during homogeneous spatial dilation {\it a priori}. We illustrate our findings with the nonlinear Kardar-Parisi-Zhang equation