scholarly journals Geometric Rényi Divergence and its Applications in Quantum Channel Capacities

Author(s):  
Kun Fang ◽  
Hamza Fawzi

AbstractHaving a distance measure between quantum states satisfying the right properties is of fundamental importance in all areas of quantum information. In this work, we present a systematic study of the geometric Rényi divergence (GRD), also known as the maximal Rényi divergence, from the point of view of quantum information theory. We show that this divergence, together with its extension to channels, has many appealing structural properties, which are not satisfied by other quantum Rényi divergences. For example we prove a chain rule inequality that immediately implies the “amortization collapse” for the geometric Rényi divergence, addressing an open question by Berta et al. [Letters in Mathematical Physics 110:2277–2336, 2020, Equation (55)] in the area of quantum channel discrimination. As applications, we explore various channel capacity problems and construct new channel information measures based on the geometric Rényi divergence, sharpening the previously best-known bounds based on the max-relative entropy while still keeping the new bounds single-letter and efficiently computable. A plethora of examples are investigated and the improvements are evident for almost all cases.

2018 ◽  
Vol 159 (50) ◽  
pp. 2144-2149
Author(s):  
Beáta Benke ◽  
Gyula Marada ◽  
Miklós Tunyogi Csapó ◽  
Péter Than ◽  
Márta Radnai

Abstract: From an anatomic and functional point of view, the stomatognathic system and the upper cervical spine are closely connected. Together with the complex neuromuscular relationships, this generates an important field of cooperation between dentists and orthopedics. The aim of this case report was to demonstrate the improvements of temporomandibular joint (TMJ) function after orthopedic surgery in case of a patient with idiopathic scoliosis. A 15-year-old female patient who had adolescent idiopathic scoliosis was surgically treated in 2016. Functional analyses of the TMJ were performed before the day of the operation and 10 months after the surgery. For detection, an ultrasound-based testing machine was used. The analyses of the data showed that almost all ranges of motions (ROM) were improved. The deviation to the right side was reduced from 8 mm to 2 mm during mouth opening. The patient had limited left lateral movement before the operation, however, after 10 months following the operation, there were free motions towards both sides. The originally asymmetrical protrusion became almost completely symmetrical. Regarding the functions of the TMJ, the surgery was successful; this in itself had a beneficial effect on the range and the path of the mandibular movements without any other treatment. These improved functions are indirect evidences for the connection of the function of the spine and TMJ. Orv Hetil. 2018; 159(50): 2144–2149.


Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 387
Author(s):  
Hamza Fawzi ◽  
Omar Fawzi

We introduce a new quantum Rényi divergence Dα# for α∈(1,∞) defined in terms of a convex optimization program. This divergence has several desirable computational and operational properties such as an efficient semidefinite programming representation for states and channels, and a chain rule property. An important property of this new divergence is that its regularization is equal to the sandwiched (also known as the minimal) quantum Rényi divergence. This allows us to prove several results. First, we use it to get a converging hierarchy of upper bounds on the regularized sandwiched α-Rényi divergence between quantum channels for α>1. Second it allows us to prove a chain rule property for the sandwiched α-Rényi divergence for α>1 which we use to characterize the strong converse exponent for channel discrimination. Finally it allows us to get improved bounds on quantum channel capacities.


2002 ◽  
Vol 16 (3) ◽  
pp. 129-149 ◽  
Author(s):  
Boris Kotchoubey

Abstract Most cognitive psychophysiological studies assume (1) that there is a chain of (partially overlapping) cognitive processes (processing stages, mechanisms, operators) leading from stimulus to response, and (2) that components of event-related brain potentials (ERPs) may be regarded as manifestations of these processing stages. What is usually discussed is which particular processing mechanisms are related to some particular component, but not whether such a relationship exists at all. Alternatively, from the point of view of noncognitive (e. g., “naturalistic”) theories of perception ERP components might be conceived of as correlates of extraction of the information from the experimental environment. In a series of experiments, the author attempted to separate these two accounts, i. e., internal variables like mental operations or cognitive parameters versus external variables like information content of stimulation. Whenever this separation could be performed, the latter factor proved to significantly affect ERP amplitudes, whereas the former did not. These data indicate that ERPs cannot be unequivocally linked to processing mechanisms postulated by cognitive models of perception. Therefore, they cannot be regarded as support for these models.


Author(s):  
Gregor Volberg

Previous studies often revealed a right-hemisphere specialization for processing the global level of compound visual stimuli. Here we explore whether a similar specialization exists for the detection of intersected contours defined by a chain of local elements. Subjects were presented with arrays of randomly oriented Gabor patches that could contain a global path of collinearly arranged elements in the left or in the right visual hemifield. As expected, the detection accuracy was higher for contours presented to the left visual field/right hemisphere. This difference was absent in two control conditions where the smoothness of the contour was decreased. The results demonstrate that the contour detection, often considered to be driven by lateral coactivation in primary visual cortex, relies on higher-level visual representations that differ between the hemispheres. Furthermore, because contour and non-contour stimuli had the same spatial frequency spectra, the results challenge the view that the right-hemisphere advantage in global processing depends on a specialization for processing low spatial frequencies.


2018 ◽  
Vol 3 (5) ◽  
pp. 39
Author(s):  
Yéssica Elizabeth Barreto Macías ◽  
Colón Avellán Velásquez

El actual trabajo afronta una de las problemáticas más apremiantes de los actuales momentos como es el alto índice de dispendio de drogas en las Instituciones Educativas, que afectan considerablemente a la sociedad ecuatoriana. Su objetivo es analizar los lineamientos que permitan mejorar la orientación familiar, y desarrollar relaciones interpersonales apropiadas que fomenten la unión familiar, practicar principios, fomentar valores morales, y que los jóvenes aprendan a decir “no” ante una eventual propuesta de consumir compuestos prohibidos, que lo único que se consigue es materializarse en un estado no idóneo ante la comunidad, considerar que las consecuencias para la salud son devastadoras, personas que a temprana edad padecen de enfermedades que en muchas ocasiones son gravísimas, causando malestar no solamente propio sino a la familia. Puedo mencionar como aporte de este artículo; y en base a resultados establecidos que resulta primordial e importante mantener la asistencia de un profesional especializado en psicología, diálogos científicos y motivadores, conjuntamente con atención médica provocarán en la persona afectada la erradicación del consumo de drogas. Constan muchos factores que causan gran influencia negativa en las familias, partiendo de que actualmente el mundo vive la tendencia del consumismo lo que influye en sobremanera que exista menos dialogo en el hogar, la aparición de la tecnología es otra de las situaciones adversas. Los profesionales encargados de brindar orientación familiar deben considerar siempre, que el comportamiento del ser humano debe ser comprendido desde el punto de vista de su forma de pensar, solo así se desarrollara una cultura que permita a las familias tomar las decisiones acertadas al momento de formar a sus hijos, lo que en un futuro se evidenciará como seres útiles a la sociedad. PALABRAS CLAVE: Consumo de drogas; orientación familiar; valores morales.  FAMILY COUNSELING, FOR THE PREVENTION OF DRUG USE IN THIRDYEAR HIGH SCHOOL STUDENTS  ABSTRACT  The current work addresses one of the most pressing issues of current times such as the high rate of drug use in educational institutions, which greatly affect Ecuadorian society. Its objective is to analyze the guidelines for improving family orientation, and develop appropriate interpersonal relationships that promote family unity, value the principles, and that young people learn to say "no" to a possible proposal to use prohibited drugs, that the only thing that is achieved is to materialize in an unsuitable state before the community, to consider that the consequences for health are devastating, people who at an early age suffer from diseases that in many occasions are very serious, causing discomfort not only their own but also the family. I can mention as contribution of this article; and based on established results that it is essential and important to maintain the assistance of a professional specialized in psychology, scientific and motivational dialogues, together with medical care, will cause the affected person to eradicate drug use. There are many factors that cause great negative influence on families, based on the fact that the world currently lives the trend of consumerism which greatly influences that there is less dialogue at home, the emergence of technology is another of the adverse situations. The professionals responsible for providing family counseling should always consider that the behavior of the human being should be understood from the point of view of their way of thinking, only in this way will a culture be developed that allows families to make the right decisions when forming to their children, which in the future will be evident as useful beings to society. KEYWORDS: drug use; family orientation; moral values.


Author(s):  
Monika Lewandowska ◽  
Rafał Milner ◽  
Małgorzata Ganc ◽  
Elżbieta Włodarczyk ◽  
Joanna Dołżycka ◽  
...  

AbstractThere are discrepancies in the literature regarding the course of central auditory processes (CAP) maturation in typically developing children and adolescents. The purpose of the study was to provide an overview of age – related improvement in CAP in Polish primary and secondary school students aged 7–16 years. 180 children/adolescents, subdivided into 9 age categories, and 20 adults (aged 18–24 years) performed the Dichotic Digit Test (DDT), Duration Pattern Test (DPT), Frequency Pattern Test (FPT), Gap Detection Test (GDT) and adaptive Speech-in-Noise (aSpN). The 12-year-olds was retested after w week. We found the age effects only for the DDT, DPT and FPT. In the right ear DDT the 7-year-olds performed more poorly than all groups ≥12. In the left ear DDT both 7- and 8-year-olds achieved less correct responses compared with the 13-, 14-, 15-year-olds and with the adults. The right ear advantage was greater in the 7-year-olds than in the 15-year-olds and adult group. At the age of 7 there was lower DPT and FPT scores than in all participants ≥13 whereas the 8-year-olds obtained less correct responses in the FPT than all age categories ≥12. Almost all groups (except for the 7-year-olds) performed better in the DPT than FPT. The test-retest reliability for all tests was satisfactory. The study demonstrated that different CAP have their own patterns of improvement with age and some of them are specific for the Polish population. The psychoacoustic battery may be useful in screening for CAP disorders in Poland.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sung Eun Kim ◽  
Jangyun Lee ◽  
Sae Yong Lee ◽  
Hae-Dong Lee ◽  
Jae Kun Shim ◽  
...  

AbstractThe purpose of this study was to investigate how the ball position along the mediolateral (M-L) direction of a golfer causes a chain effect in the ground reaction force, body segment and joint angles, and whole-body centre of mass during the golf swing. Twenty professional golfers were asked to complete five straight shots for each 5 different ball positions along M-L: 4.27 cm (ball diameter), 2.14 cm (ball radius), 0 cm (reference position at preferred ball position), – 2.14 cm, and – 4.27 cm, while their ground reaction force and body segment motions were captured. The dependant variables were calculated at 14 swing events from address to impact, and the differences between the ball positions were evaluated using Statistical Parametric Mapping. The left-sided ball positions at address showed a greater weight distribution on the left foot with a more open shoulder angle compared to the reference ball position, whereas the trend was reversed for the right-sided ball positions. These trends disappeared during the backswing and reappeared during the downswing. The whole-body centre of mass was also located towards the target for the left-sided ball positions throughout the golf swing compared to the reference ball position, whereas the trend was reversed for the right-sided ball positions. We have concluded that initial ball position at address can cause a series of chain effects throughout the golf swing.


Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 299
Author(s):  
Vítor Ennes-Vidal ◽  
Marta Helena Branquinha ◽  
André Luis Souza dos Santos ◽  
Claudia Masini d’Avila-Levy

Calpains are calcium-dependent cysteine peptidases that were originally described in mammals and, thereafter, their homologues were identified in almost all known living organisms. The deregulated activity of these peptidases is associated with several pathologies and, consequently, huge efforts have been made to identify selective inhibitors. Trypanosomatids, responsible for life-threatening human diseases, possess a large and diverse family of calpain sequences in their genomes. Considering that the current therapy to treat trypanosomatid diseases is limited to a handful of drugs that suffer from unacceptable toxicity, tough administration routes, like parenteral, and increasing treatment failures, a repurposed approach with calpain inhibitors could be a shortcut to successful chemotherapy. However, there is a general lack of knowledge about calpain functions in these parasites and, currently, the proteolytic activity of these proteins is still an open question. Here, we highlight the current research and perspectives on trypanosomatid calpains, overview calpain description in these organisms, and explore the potential of targeting the calpain system as a therapeutic strategy. This review gathers the current knowledge about this fascinating family of peptidases as well as insights into the puzzle: are we unable to measure calpain activity in trypanosomatids, or are the functions of these proteins devoid of proteolytic activity in these parasites?


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hicham Agueny

AbstractCoherent electron displacement is a conventional strategy for processing quantum information, as it enables to interconnect distinct sites in a network of atoms. The efficiency of the processing relies on the precise control of the mechanism, which has yet to be established. Here, we theoretically demonstrate a new route to drive the electron displacement on a timescale faster than that of the dynamical distortion of the electron wavepacket by utilizing attosecond single-cycle pulses. The characteristic feature of these pulses relies on a vast momentum transfer to an electron, leading to its displacement following a unidirectional path. The scenario is illustrated by revealing the spatiotemporal nature of the displaced wavepacket encoding a quantum superposition state. We map out the associated phase information and retrieve it over long distances from the origin. Moreover, we show that a sequence of such pulses applied to a chain of ions enables attosecond control of the directionality of the coherent motion of the electron wavepacket back and forth between the neighbouring sites. An extension to a two-electron spin state demonstrates the versatility of the use of these pulses. Our findings establish a promising route for advanced control of quantum states using attosecond single-cycle pulses, which pave the way towards ultrafast processing of quantum information as well as imaging.


2021 ◽  
pp. 174701612110082
Author(s):  
Nicole Podschuweit

This paper aims to bring into the ethical debate on covert research two aspects that are neglected to date: the perspective of the research subjects and the special responsibility of investigators towards their observers. Both aspects are falling behind, especially in quantitative social research. From a methodological point of view, quantitative forms of covert observation involve a great distance between the researcher and the research subjects. When human observers are involved, the focus is usually on the reliable application of the measuring instrument. Therefore, herein, a quantitative study is used as an example to show how the protection needs of both the observed persons and the observers can be met in practice. The study involved 40 student observers who covertly captured everyday conversations in real-world settings (e.g. in cafés or trains) by a highly standardised observation scheme. The study suggests that the anonymity of the research subjects and their trust in the observers are crucial for their subsequent consent. However, many participants showed only little or even no interest in the written information they were provided. Further, this study strongly emphasises how mentally stressful covert observations are to the observers. Almost all observers were worried in advance that the people they were observing would prematurely blow their cover and confront them. Role-playing and in-depth discussions in teams are good strategies to alleviate such and other fears and to prepare student assistants well for their demanding work in the field.


Sign in / Sign up

Export Citation Format

Share Document