Towards a Spectroscopic Protocol for Unambiguous Detection of Quantum Coherence in Excitonic Energy Transport

The role of quantum effects in excitonic energy transport (EET) has been scrutinised intensely and with increasingly sophisticated experimental techniques. This increased complexity requires invoking correspondingly elaborate models to fit spectroscopic data before molecular parameters can be extracted. Possible quantum effects in EET can then be studied, but the conclusions are strongly contingent on the efficacy of the fitting and the accuracy of the model. To circumvent this challenge, we propose a witness for quantum coherence in EET that can be extracted directly from two-pulse pump-probe spectroscopy experimental data. We provide simulations to judge the feasibility of our approach. Somewhat counterintuitively, our protocol does not probe quantum coherence directly, but only indirectly through its implicit deletion. It allows for classical models with no quantum coherence to be decisively ruled out.Comment: 13 pages, 9 figure

Bayesian Inference in Estimation of Distribution Algorithms

Metaheuristics such as Estimation of Distribution Algorithms and the Cross-Entropy method use probabilistic modelling and inference to generate candidate solutions in optimization problems. The model fitting task in this class of algorithms has largely been carried out to date based on maximum likelihood. An alternative approach that is prevalent in statistics and machine learning is to use Bayesian inference. In this paper, we provide a framework for the application of Bayesian inference techniques in probabilistic model-based optimization. Based on this framework, a simple continuous Bayesian Estimation of Distribution Algorithm is described. We evaluate and compare this algorithm experimentally with its maximum likelihood equivalent, UMDAG c

Subtleties of witnessing quantum coherence in non-isolated systems

Identifying non-classicality unambiguously and inexpensively is a long-standing open challenge in physics. The No-Signalling-In-Time protocol was developed as an experimental test for macroscopic realism, and serves as a witness of quantum coherence in isolated quantum systems by comparing the quantum state to its completely dephased counterpart. We show that it provides a lower bound on a certain resource-theoretic coherence monotone. We go on to generalise the protocol to the case where the system of interest is coupled to an environment. Depending on the manner of the generalisation, the resulting witness either reports on system coherence alone, or on a disjunction of system coherence with either (i) the existence of non-classical system-environment correlations or (ii) non-negligible dynamics in the environment. These are distinct failure modes of the Born approximation in non-isolated systems.Comment: 16pp, 2 figs, 5 thms. v2: typos corrected, references added and small change to title to reflect that of published versio

The Ethnographic Subject as Ethnographer: A Neglected Dimension of Anthropological Research

Paper by George E. Marcu

El o los fines de la etnografía: del desorden de lo experimental al desorden de lo barroco

Desde los pasados años ochenta, con la crítica a la representación etnográfica de Writing Culture, la escritura de textos etnográficos en antropología se ha distinguido por la aparición perenne de neófitos de nuevos trabajos compuestos de tropos y estrategias estilísticas que reflejan las diversas influencias de un periodo de crítica. Estos textos “desordenados” eran, y son, valorados como experimentos. Este ensayo argumenta como crítica, que estas etnografías actuales no son tanto experimentales como barrocas, indicando quizá un límite a la forma etnográfica histórica y la necesidad de empujar de nuevo el espíritu de lo experimental hacia las condiciones de producir etnografía en el trabajo de campo. Esta “refuncionalización” de la etnografía en su espíritu experimental reconocería y abordaría el límite presente de lo barroco, al que este periodo de crítica nos ha conducido de los últimos años ochenta en adelante.Since the 1980s, and the Writing Culture critique of ethnographic representation, the writing of ethnographic texts in anthropology has been distinguished by the perennial appearance by neophytes of new works composed of tropes and stylistic strategies that reflect the diverse influences of the period of critique. These “messy” texts were, and are, valorizied as experiments. This essay argues as critique that current such ethnographies are not so much experimental as baroque. Indicating perhaps a limit of the historic ethnographic form, and the need to push the spirit of experiment back toward the conditions of producing ethnography in fieldwork. This “refunctioning” of ethnography in its experimental spirit would recognize and address the present limit of the baroque to which the 1980s period of critique and after has led

The role of cognitive schemas in a web-based student evaluation of teaching system: usability issues of design and implementation

With the increase in the use of web-based student evaluations of teaching (SETs) by institutions of higher education, the importance of understanding the usability of such web-based systems has increased. Such understanding is needed to ensure that web-based SETs produce the best information possible. By using schema theory from cognitive psychology as a backdrop, this study seeks to identify the impact that the method of response and grouping of items displayed per page have on the usability of web-based SETs. Issues of user satisfaction, error rate, and time on task are examined. Participants were divided into one of six similarity groups based on the degree to which participant expectation and the design of the web-based SET system matched. Analyzing data from 791 university students at a large southern University, it was determined that the use of a radio-button response format with SET items grouped by area produces the best results from a usability perspective. The use of drop-down boxes and text boxes is discouraged as a response format. Limitations of this study and suggested directions for future research are discussed.Educational Psycholog