Matrix diagonalization and exact solution of the k-photon Jaynes-Cummings model

We study and exactly solve the two-photon and k-photon Jaynes-Cummings models by using a novelty algebraic method. This algebraic method is based on the Pauli matrices realization and the tilting transformation of the $SU(2)$ group and let us diagonalize the Hamiltonian of these models by properly choosing the coherent state parameters of the transformation. Finally, we explicitly obtain the energy spectrum and eigenfunctions for each model.Comment: 12 page

Position and Orientation Estimation through Millimeter Wave MIMO in 5G Systems

Millimeter wave signals and large antenna arrays are considered enabling technologies for future 5G networks. While their benefits for achieving high-data rate communications are well-known, their potential advantages for accurate positioning are largely undiscovered. We derive the Cram\'{e}r-Rao bound (CRB) on position and rotation angle estimation uncertainty from millimeter wave signals from a single transmitter, in the presence of scatterers. We also present a novel two-stage algorithm for position and rotation angle estimation that attains the CRB for average to high signal-to-noise ratio. The algorithm is based on multiple measurement vectors matching pursuit for coarse estimation, followed by a refinement stage based on the space-alternating generalized expectation maximization algorithm. We find that accurate position and rotation angle estimation is possible using signals from a single transmitter, in either line-of- sight, non-line-of-sight, or obstructed-line-of-sight conditions.Comment: The manuscript has been revised, and increased from 27 to 31 pages. Also, Fig.2, Fig. 10 and Table I are adde

Perspectives on Tobacco Product Waste: A Survey of Framework Convention Alliance Members' Knowledge, Attitudes, and Beliefs.

Cigarette butts (tobacco product waste (TPW)) are the single most collected item in environmental trash cleanups worldwide. This brief descriptive study used an online survey tool (Survey Monkey) to assess knowledge, attitudes, and beliefs among individuals representing the Framework Convention Alliance (FCA) about this issue. The FCA has about 350 members, including mainly non-governmental tobacco control advocacy groups that support implementation of the World Health Organization's (WHO) Framework Convention on Tobacco Control (FCTC). Although the response rate (28%) was low, respondents represented countries from all six WHO regions. The majority (62%) have heard the term TPW, and nearly all (99%) considered TPW as an environmental harm. Most (77%) indicated that the tobacco industry should be responsible for TPW mitigation, and 72% felt that smokers should also be held responsible. This baseline information may inform future international discussions by the FCTC Conference of the Parties (COP) regarding environmental policies that may be addressed within FCTC obligations. Additional research is planned regarding the entire lifecycle of tobacco's impact on the environment

Superconducting/magnetic three state nanodevice for memory and reading applications

We present a simple nanodevice that can operate in two modes: i) three-state memory and ii) reading device. The nanodevice is fabricated with an array of ordered triangular-shaped nanomagnets embedded in a superconducting thin film. The input signal is ac current and the output signal is dc voltage. Vortex ratchet effect in combination with out of plane magnetic anisotropy of the nanomagnets is the background physics which governs the nanodevice performance.Comment: 10 pages, 4 figure

The Role of Social and Technological Predispositions in Participation in the Sharing Economy

This study contributes to the growing body of research on drivers of participation in the sharing economy. We extend the well-established technology acceptance model and include layers of personality architecture related to the social nature of these markets (extraversion) and their technology intermediation (technology proclivity). Findings from a cross-sectional survey (n = 292) show that extraversion is related directly to the intention to use sharing economy applications, such as in home gig services, and related indirectly to likelihood to use these technologies and to engage as a provider of such services, through technology proclivity and the technology’s perceived usefulness

Caracterización de trenes de descargas preliminares en rayos nube a tierra negativos registrados durante una temporada de lluvias en la Sabana de Bogotá, Colombia

Lightning-generated electric field measurement is used to characterize cloud-to-ground (CG) flashes. Prior to the first return stroke (FRS), these signals sometimes exhibit a pulse train, known as preliminary breakdown pulses (PBP), whose study provides information about the first event that originate the breakdown process inside the cloud. Considering that characteristics of PBPs may change according to geographical conditions, in this work, six parameters (temporal and magnitude) associated with 69 trains identified in negative CG flashes that occurred in the Bogota savannah, Colombia were analyzed. The signatures were recorded in 2017 using a fast response antenna (10 MHz bandwidth), a 100 ns sampling time and a window of 500 ms. Among the most relevant results, it was found that the train duration ( ) varied from 0.5 ms up to 5.2 ms with arithmetic mean (AM) of 1.74 ms, while the time interval between the peak of the train and the FRS (PBP-FRS) had an AM and a geometric mean (GM) of 35.7 ms and 10.2 ms, respectively. On the other hand, the ratio between the peak value of the PBP and its FRS ( ) exhibited an AM of 0.7 and a GM of 0.56. It was concluded that PBP train starts with low amplitude pulses, later increases its magnitude in the central region and decreases at the end. Furthermore, bipolar pulses with similar polarity to that of the FRS were identified at the beginning and in the middle of the train, while unipolar pulses were observed at the end of the signatures.La medición del campo eléctrico generado por rayos es comúnmente usada para caracterizar rayos nube-tierra (CG). Previo a la primera descarga de retorno (FRS), estas señales exhiben algunas veces un tren de pulsos conocido como pulsos de descargas preliminares (PBP), cuyo estudio proporciona información sobre el primer evento que origina el proceso de descarga dentro de la nube. Considerando que las características de los PBP pueden cambiar de acuerdo con las condiciones geográficas, en este trabajo se analizaron seis parámetros (temporales y de magnitud) asociados a 69 trenes identificados en rayos CG negativos ocurridos en la Sabana de Bogotá, Colombia. Las señales se registraron en 2017 usando una antena de respuesta rápida (ancho de banda de 10 MHz), un tiempo de muestreo de 100 ns y una ventana de 500 ms. Dentro de los resultados más relevantes se encontró que la duración del tren ( ) varió entre 0.5 ms y 5.2 ms con una media aritmética (AM) de 1.74 ms, mientras el tiempo entre el pico del tren y el FRS (PBP-FRS) tuvo una AM y una media geométrica (GM) de 35.7 ms y 10.2 ms, respectivamente. Por su parte, la relación entre el pico del PBP y su FRS ( ) exhibió una AM de 0.7 y una GM de 0.56. Se concluye que el tren comienza con pulsos de baja amplitud, aumenta su magnitud en la región central y disminuye al final. Adicionalmente, se identificaron pulsos bipolares con polaridad similar a la FRS al principio y en la mitad del tren, mientras pulsos unipolares fueron observados al final de las señales

A glimpse into the diversity of Colombian Acanthaceae

Summary: A short visit to four Colombian herbaria in 2022 is highlighted as an example of modern-day herbarium plant hunting which resulted in the discovery of 14 new species: Aphelandra guacharorum J.R.I.Wood, A. montis-tusae J.R.I.Wood & Hoyos-Gómez, Justicia betancurii J.R.I.Wood, J. chloroleuca J.R.I.Wood, J. cristalina J.R.I.Wood & Hoyos-Gómez, J. daironcardenasii J.R.I.Wood & Hoyos-Gómez, J. ipanorensis J.R.I.Wood, J. lutescens J.R.I.Wood & Hoyos-Gómez, J. macuirensis J.R.I.Wood, J. perijaensis J.R.I.Wood, J. reniformis J.R.I.Wood, J. rheophytica J.R.I.Wood & Hoyos-Gómez J. santanderana J.R.I.Wood & Hoyos-Gómez and Ruellia rheophytica J.R.I.Wood & Hoyos-Gómez. These are described and illustrated with line drawings. Additionally, a full description and line drawings of two poorly known species, Justicia hochreutineri J.F.Macbr. and J. trianae (Leonard) J.R.I.Wood are provided. Notes are provided on 21 other species drawing attention to new records for Colombia, rediscoveries and taxonomic issues. Justicia hochreutineri J.F.Macbr., J. pilosa (Ruiz ex Nees) Lindau, J. zamorensis Wassh. and Stenostephanus lasiostachyus Nees are recorded for the first time for Colombia. Justicia pampolystachys Leonard is treated as a synonym of J. hyperdasya Leonard. Poikilacanthus moritzianus (Nees) Lindau is shown to be restricted to Venezuela. Adhatoda pilosa Ruiz ex Nees is lectotypified. Attention is drawn to the number of rheophytes in Colombian Acanthaceae and to the importance of the Río Claro and Río Samaná Norte area of Antioquia as a centre of plant diversity