On the exact continuous mapping of fermions

We derive a rigorous, quantum mechanical map of fermionic creation and annihilation operators to continuous Cartesian variables that exactly reproduces the matrix structure of the many-fermion problem. We show how our scheme can be used to map a general many-fermion Hamiltonian and then consider two specific models that encode the fundamental physics of many fermionic systems, the Anderson impurity and Hubbard models. We use these models to demonstrate how efficient mappings of these Hamiltonians can be constructed using a judicious choice of index ordering of the fermions. This development provides an alternative exact route to calculate the static and dynamical properties of fermionic systems and sets the stage to exploit the quantum-classical and semiclassical hierarchies to systematically derive methods offering a range of accuracies, thus enabling the study of problems where the fermionic degrees of freedom are coupled to complex anharmonic nuclear motion and spins which lie beyond the reach of most currently available methods.Comment: 7-page manuscript (2 figures) with 11-page supplemental materia

Preparing for Interview Research: The Interview Protocol Refinement Framework

This article presents the interview protocol refinement (IPR) framework comprised of a four-phase process for systematically developing and refining an interview protocol. The four-phase process includes: (1) ensuring interview questions align with research questions, (2) constructing an inquiry-based conversation, (3) receiving feedback on interview protocols, and (4) piloting the interview protocol. The IRP method can support efforts to strengthen the reliability of interview protocols used for qualitative research and thereby contribute to improving the quality of data obtained from research interviews

Painting sampler: un spleen aceleracionista

Mi proyecto se interesa temáticamente por el modo en el que el individuo contemporáneo es afectado por una gran saturación de ofertas de consumo, sobre todo desde el punto de vista de su fuerte potencia visual y de cómo ello puede relacionarse con la práctica de la pintura. Esto es atendido mediante la investigación de las posibilidades de construcción pictórica, abarcando las técnicas de la pintura al óleo, la acuarela, el ensamblaje, el collage, la cerámica y la intervención sobre revistas, libros y catálogos. Por tanto, tomando el collage como base estructural de mi producción, tensiono la violencia compositiva con la necesidad de crear una fuerte unicidad atsmosférica de cada cuadro, para hacer una relectura de ciertos géneros pictóricos como la pintura de interiores, el bodegón, el paisaje y la alegoría desde mi presente, con referencias a tradiciones y estrategias artísticas como el Pop-art, el Neoexpresionismo, el kitsch, la “Bad painting”, el Simbolismo o el Surrealismo, o a autores y corrientes extra-artísticas como la literatura beat, en especial Wiliam Burroughs, o Charles Bukowski, además de otros autores como Baudelaire o el Marqués de Sade, o ámbitos estéticos populares como la ilustración, Instagram o el vaporwave

Compact and complete description of non-Markovian dynamics

Generalized master equations provide a theoretically rigorous framework to capture the dynamics of processes ranging from energy harvesting in plants and photovoltaic devices, to qubit decoherence in quantum technologies, and even protein folding. At their center is the concept of memory. The explicit time-nonlocal description of memory is both protracted and elaborate. When physical intuition is at a premium one would desire a more compact, yet complete, description. Here, we demonstrate how and when the time-convolutionless formalism constitutes such a description. In particular, by focusing on the dissipative dynamics of the spin-boson and Frenkel exciton models, we show how to: easily construct the time-local generator from reference reduced dynamics, elucidate the dependence of its existence on the system parameters and the choice of reduced observables, identify the physical origin of its apparent divergences, and offer analysis tools to diagnose their severity and circumvent their deleterious effects. We demonstrate that, when applicable, the time-local approach requires as little information as the more commonly used time-nonlocal scheme, with the important advantages of providing a more compact description, greater algorithmic simplicity, and physical interpretability. We conclude by introducing the discrete-time analogue and a straightforward protocol to employ it in cases where the reference dynamics have limited resolution. The insights we present here offer the potential for extending the reach of dynamical methods, reducing both their cost and conceptual complexity.Comment: 9 pages, 8 figures main text + 6 pages, 5 figures of appendices and references. updated to reflect helpful discussion

Efficient formulation of multitime generalized quantum master equations: Taming the cost of simulating 2D spectra

Modern 4-wave mixing spectroscopies are expensive to obtain experimentally and computationally. In certain cases, the unfavorable scaling of quantum dynamics problems can be improved using a generalized quantum master equation (GQME) approach. However, the inclusion of multiple (light-matter) interactions complicates the equation of motion and leads to seemingly unavoidable cubic scaling in time. In this paper, we present a formulation that greatly simplifies and reduces the computational cost of previous work that extended the GQME framework to treat arbitrary numbers of quantum measurements. Specifically, we remove the time derivatives of quantum correlation functions from the modified Mori-Nakajima-Zwanzig framework by switching to a discrete-convolution implementation inspired by the transfer-tensor approach. We then demonstrate the method's capabilities by simulating 2D electronic spectra for the excitation-energy-transfer dimer model. In our method, the resolution of the data can be arbitrarily coarsened, especially along the $t_2$ axis, which mirrors how the data are obtained experimentally. Even in a modest case, this demands $\mathcal{O}(10^3)$ fewer data points. We are further able to decompose the spectra into 1-, 2-, and 3-time correlations, showing how and when the system enters a Markovian regime where further measurements are unnecessary to predict future spectra and the scaling becomes quadratic. This offers the ability to generate long-time spectra using only short-time data, enabling access to timescales previously beyond the reach of standard methodologies.Comment: 10 pages, 5 figures, 3 pages of appendix and 81 citation

Selection, tinkering and emergence in complex networks: crossing the land of tinkering

Complex biological networks have very different origins than technologic ones. The latter involve extensive design and, as engineered structures, include a high level of optimization. The former involve (in principle) contingency and structural constraints, with new structures being incorporated through tinkering with previously evolved modules or units. However, the observation of the topological features of different biological nets suggests that nature can have a limited repertoire of ”attractors” that essentially optimize communication under some basic constraints of cost and architecture or that allow the biological nets to reach a high degree of homeostasis. Conversely, the topological features exhibited by some technology graphs indicate that tinkering and internal constraints play a key role, in spite of the ”designed” nature of these structures. Previous scenarios suggested to explain the overall trends of evolution are re-analyzed in light of topological patterns.Peer ReviewedPostprint (author's final draft

Current and future training needs of international business graduates regarding the supply and demand of human talent in the port sector of Santa Marta

The objective of this article is to highlight the present and future training needs of the professional in international business regarding the educational offer and the labor demand, in terms of human talent in the port sector of the Tourist, Historic and Cultural District of Santa Marta. As a first step, different scenarios will be presented around the world in which the close relationship between the port sector and the education sector has brought benefits to the countries; Followed by that will proceed to transfer the object of study to the Colombian environment, and specifically to the city of Santa Marta and its port sector, here with data and information provided by the main actors involved (Port sector and educational establishments) will be revealed What is the level of integration of these two sectors in the region; Finally, once the data and results are presented, it will conclude with a reflection on the current and future situation of the port sector in the city of Santa Marta.El objetivo del artículo es evidenciar las necesidades formativas, actuales y futuras, del profesional en negocios internacionales respecto a la oferta educativa y a la demanda laboral, en términos de talento humano en el sector portuario del Distrito Turístico, Histórico y Cultural de Santa Marta. Como primera medida, se realizará un análisis sobre los distintos factores que inciden en la competitividad del sector portuario; seguido a eso se procederá a estudiar específicamente el rol del talento humano dentro del crecimiento y desarrollo de los distintos sectores portuarios; siguiente a esto se trasladara el objeto de estudio a la ciudad de Santa Marta y a su sector portuario, aquí con datos e información proporcionada por los actores principales que intervienen (Sector portuario y planteles educativos) se revelará cual es el nivel de integración de estos dos sectores en la región y como se ve afectada la competitividad del sector en base a esto; finalmente una vez expuestos los datos y los resultados, se concluirá con una reflexión sobre la situación actual y futura del sector portuaria en la ciudad de Santa Marta

Sectores Económicos : La inversión extranjera directa y su relación con el crecimiento económico y los salarios manufactureros en Nicaragua, periodo 2006-2015

En el presente Capítulo se abordan los Aspectos Teóricos-Metodológicos de la investigación ¨La inversión Extranjera Directa y su relación con el Crecimiento Económico y los Salarios Manufactureros en Nicaragua período (2009-2013) ¨. En donde se pone de manifiesto: el Planteamiento del Problema, Justificación e importancia de la investigación, Objetivos, Marco Teórico, Hipótesis, variables en la investigación y por último la Metodologí