Exotic Ways Research Articles

Topology and retardation effect of a giant atom in a topological waveguide

The interaction between the quantum emitter and topological photonic system makes both the emitter and the photon behave in exotic ways. We here study a system that a giant atom is coupled to two points of a one-dimensional topological waveguide formed by the Su-Schrieffer-Heeger (SSH) chain. The topological nature of the hybrid system is studied. We find that the giant atom can act as an effective boundary and induce the chiral zero energy modes for the waveguide under the periodical boundary. The properties of these modes are similar to those in the SSH model with open boundary. Meanwhile, the SSH waveguide, as a structured environment, induces the retarded effect and the non-Markovian dissipation of the giant atom. Our work may promote more studies on the interaction between matter and topological environment. Experimental demonstration for our study using superconducting quantum circuits is very possible within current technology.

Opportunities of copper addition in CH3NH3PbI3 perovskite and their photovoltaic performance evaluation

Perovskite solar cells (PSCs) have encountered a fulgurant development in their power-conversion efficiency (PCEs) generation in the drive to provide a facile, cheap and clean source of energy over just a few years. The most efficient PSCs are fabricated using CH3NH3PbI3 (MAPbI3) perovskite. However, being a promising photovoltaic (PV) performance piloted by MAPbI3, Pb-toxicity and poor stability obstructs the progress of PSCs in PV technology. In this regard, replacing Pb with some environmentally friendly, cheaper, and similar optoelectronic behaviour related alternative material or element is highly desirable. In this work, an attempt was made on copper as Cu (I) addition in the perovskite, MAPbI3 through some exotic ways in an intention of Pb replacement, i.e., complete Pb replacement with Cu, which generates MACuxI3 (1 ≤ x ≥ 2); partial lead replacement, i.e., MAPb1−xCuxI3; and cocktail perovskite, i.e., both MAPbI3 and MACuxI3 mixture, and finally they are employed for carbon-based perovskite solar cells. Remarkably, Cu incorporation facilitates the near-infrared (NIR) absorption, indicating a maximum solar spectrum absorbance. Integration of Cu as MAPb1−xCuxI3 results in the maximum PCE of ~12.85%, whereas using 1:1 cocktail perovskite solution of MAPbI3 and MACuxI3 exhibits an average PCE of ~12.43%. On the other hand, during complete Pb substituted perovskites, MACuxI3, the device has only experienced an average PCE of ~4.0%. However, MACuxI3-based PSCs lead to negligible PCE degradation as perceived up to 1000 h, whereas Pb-based other devices are experienced rapid PCE depletion over the same period. Noticeably, Cu-incorporation facilitates a comparatively steeper and lesser PCE degradation rate than Pb-based PSCs. These results may help exploit unlimited possibilities of the potential application of Pb-free based highly stable solar cells and highlights the opportunities for broad solar absorption towards the NIR route and enhanced device stability. Besides, Cu employment has the advantages of environmentally benign impact, earth abundance, good thermal and aqueous stability.

Level set splitting in DEM for modeling breakage mechanics

Brittle breakage of particles in granular materials has often been modeled using the discrete element method (DEM). DEM is often limited however in its ability to capture particle shape, particularly when used for breakage. This paper presents the first brittle breakage technique where level set functions will allow for the description of arbitrary shape for both particles and fracture surfaces. The breakage model to be described here uses fracture surfaces defined by level sets to take advantage of simple intersection and difference set operations to split particles in both two and three dimensions. We show how this method is implemented and how we can use it to define and apply arbitrary fracture surface shapes. We then give qualitative examples of using the method in both simple and exotic ways. Finally, we model oedometric tests and rock crushing, both very common uses for previous DEM breakage techniques, to present a validation that the method captures the physics of the problem.

Unconventional quantum optics in topological waveguide QED.

The discovery of topological materials has motivated recent developments to export topological concepts into photonics to make light behave in exotic ways. Here, we predict several unconventional quantum optical phenomena that occur when quantum emitters interact with a topological waveguide quantum electrodynamics bath, namely, the photonic analog of the Su-Schrieffer-Heeger model. When the emitters' frequency lies within the topological bandgap, a chiral bound state emerges, which is located on just one side (right or left) of the emitter. In the presence of several emitters, this bound state mediates topological, tunable interactions between them, which can give rise to exotic many-body phases such as double Néel ordered states. Furthermore, when the emitters' optical transition is resonant with the bands, we find unconventional scattering properties and different super/subradiant states depending on the band topology. Last, we propose several implementations where these phenomena can be observed with state-of-the-art technology.

Dielectric 2-bit coding metasurface for electromagnetic wave manipulation

The recent advent of digital coding metasurfaces notably simplifies the design of functional devices, enabling one to manipulate electromagnetic waves in exotic ways using specifically arranged coding elements representing discrete phase states. Here, we propose a design of dielectric coding metasurface with diverse functionalities, which are achieved by encoding the metasurface unit cells with different coding sequences. As proofs of concept, we demonstrate the possibility of realizing five distinct functionalities for the normal incidence of plane microwaves: anomalous reflection, multibeam generation, diffuse scattering, beam focusing, and vortex beam generation. The near-field distributions and far-field scattering patterns are obtained by full-wave numerical simulations to analyze the behavior of the waves in each of the cases and illustrate our general theoretical predictions.

Doubts and Variability: A Robust Perspective on Exotic Consumption Series

In order for consumption based asset pricing models to reconcile data on returns with that on consumption, researchers have resorted to augmenting the consumption series in exotic ways. When an agent’s consumption series is subject to changes in volatility, we show that concerns for model misspecification can induce fears of both disasters and long run risk. We appeal to this pessimistic view to explain why introducing stochastic volatility in the presence of model uncertainty helps generate a more plausible unconditional market price of risk and time variation in the conditional market price of risk. Our analysis is based on a parameterization derived from Bayesian estimation of our stochastic volatility model using US consumption data.

Silicon on the rack

In the latest processes, it is normal for silicon to be stretched, strained and compressed as process engineers use ever more exotic ways of bending the silicon lattice to get more electron mobility out of transistors. This work could eventually lead to a new generation of hybrid devices that see silicon pushed out of the way altogether.

Meeting of minds: how do we share our appreciation of traditional environmental knowledge?

Ethnography is ‘writing culture’. This requires translating terms of understanding from the exotic to the familiar. If culture is, at least in substantial part, ‘what one needs to know … to act … in a given society’, then ethnography must convey a significant body of exotic knowledge, elaborated in a foreign language, enlightening readers while holding their attention to the intricate detail of the lives described. Ethnobiology's signal contribution is to show how traditional environmental knowledge or local natural history is central to cultural knowledge, at least for the mostly rural societies that have been our prime descriptive focus. Ethnobiologists tend to share with their subjects a fascination with natural history and thus an appreciation of their environmental knowledge. However, the audience for ethnography is predominantly urban and modern, profoundly ignorant of natural history. Our challenge is double, or triple: not only must we educate our audience about exotic ways of life, but also educate this audience about the wonders of natural history, translating into our vernacular a technical conversation between our subjects and modern biologists. I will offer a few suggestions based on my own ethnographic reading and writing on how we might best meet these challenges.

Wild Europe: the Balkans in the gaze of western travellers

Combining witty comment with meticulous research abounding in historical and cultural detail, Jezernik reveals how from the mid 16th to the late 20th century have been perceived by west European travellers and experts, many of whom have seen it as part of Asia and sought accordingly to inform their contemporaries of its exotic, outlandish and primitive ways. The rich source material includes citations from naturalists, geographers, historians and social scientists: from Joseph de Tournefort and Henry Blount via Karl Baedeker, William Gladstone and Paulina Irby, to Edith Durham, Rebecca West and Julia Kristeva. Exploring over 1000 first-hand reports and comparing narratives spanning almost five centuries, the author demonstrates how the project of observing other people in their environment mirrors the observers' own culture and environment. Thus the impressions passed down through the ages about the Balkans say more about Western Europe in most respects than about the lands and people in question.

Clinical management of acute pain

The clinical management of acute pain has been impeded by traditions and misconceptions which have resulted in suboptimal application to the patient of the currently available methods of pain control. The search for new drugs and exotic ways to deliver them has further obscured many of the basic principles which should guide management. Standard regimens fail because of the wide, unpredictable variability in pain intensity, patient characteristics, and pharmacological responses. Treatment needs to be individualized for each patient. Unrelieved acute pain produces psychological, physiological and socioeconomic consequences. Pre-emptive analgesia may damp down the development of both immediate and long-term pain following surgery and adequate psychological preparation can improve coping abilities. The delivery of opioid analgesics can be improved using patient controlled analgesia or spinal administration in some cases. Regional analgesia, often using simple techniques, can produce excellent pain relief. Overall management and staff education should be delegated to an acute pain service.