Quantum phase transition as an interplay of Kitaev and Ising interactions

We study the interplay between the Kitaev and Ising interactions on both ladder and two dimensional lattices. We show that the ground state of the Kitaev ladder is a symmetry-protected topological (SPT) phase, which is protected by a $\mathbb{Z}_2 \times \mathbb{Z}_2$ symmetry. It is confirmed by the degeneracy of the entanglement spectrum and non-trivial phase factors (inequivalent projective representations of the symmetries), which are obtained within infinite matrix-product representation of numerical density matrix renormalization group. We derive the effective theory to describe the topological phase transition on both ladder and two-dimensional lattices, which is given by the transverse field Ising model with/without next-nearest neighbor coupling. The ladder has three phases, namely, the Kitaev SPT, symmetry broken ferro/antiferromagnetic order and classical spin-liquid. The non-zero quantum critical point and its corresponding central charge are provided by the effective theory, which are in full agreement with the numerical results, i.e., the divergence of entanglement entropy at the critical point, change of the entanglement spectrum degeneracy and a drop in the ground-state fidelity. The central charge of the critical points are either c=1 or c=2, with the magnetization and correlation exponents being 1/4 and 1/2, respectively. In the absence of frustration, the 2D lattice shows a topological phase transition from the $\mathbb{Z}_2$ spin-liquid state to the long-range ordered Ising phase at finite ratio of couplings, while in the presence of frustration, an order-by-disorder transition is induced by the Kitaev term. The 2D classical spin-liquid phase is unstable against the addition of Kitaev term toward an ordered phase before the transition to the $\mathbb{Z}_2$ spin-liquid state.Comment: 16 pages, 18 figure

Quantum Processing Framework And Hybrid Algorithms For Routing Problems

The theory of quantum complexity determines when quantum computers may offer a computational speed-up over classical computers. At present, there are only a few general well-known techniques in the field of quantum computing and finding the problems that are amenable to quantum speedups is a high priority. Nonetheless, efficient quantum algorithms are very limited in number and scope; no real breakthrough has yet been achieved in physical implementations. Most importantly, these algorithms are not still matured adequately to be applied in real quantum computations. The Quantum Processing Unit (QPU) is the processor of quantum computer that is able to do quantum computations. A typical component in QPU is a quantum device that runs quantum algorithms; namely Quantum Algorithm Processing Unit (QAPU). The focus of this study is developing a framework of QAPU and hybrid architecture for classical-quantum algorithms. The framework is used to increase the implementation performance of quantum algorithms. The framework shows a general plan for the architecture of quantum processor which is capable to run the quantum algorithms. In particular, QAPU can be used as a quantum node to design a quantum multicomputer. A uniform platform was proposed for the QAPU used in the present study. At first, the hybrid architecture was designed for the quantum algorithms. Then, the relationship between classical and quantum parts of the hybrid algorithms were extracted and the main stages of the hybrid algorithm were determined. Next, the framework of QAPU was designed and developed. For this purpose, some gates and connections were projected in the framework which could be applied for future quantum algorithms. Furthermore, the framework was set up, implemented and simulated for the existing quantum algorithms on a classic computer. The results were shown that the framework is appropriate for the quantum algorithms and had been mathematically proven. Moreover, a quantum algorithm was designed to solve the shortest paths problem between the two points in a network. Another quantum algorithm for a minimum weight spanning tree in the graph was also designed. These quantum algorithms can be applied to solve routing problem in the quantum networks and the quantum multicomputer. The designed hybrid architecture and framework were tested using the above quantum algorithms and the existing quantum algorithms. Implementing and simulating results are then represented based on the probabilistic hybrid algorithm in the case of linear array, binary heap and quantum search for dense and sparse graphs

Literary Techniques of Marquez’s Literary Discourse

The literary techniques of Gabriel Garcia Marquez’s novels deal with his literary devices and figurative language which he has applied in his novels. These devices basically serve as socio-symbolic mediations that relate the literary text to his culture. For this reason, Marquez has immensely applied the figurative elements in his novels, making a bridge between his works and the world to which he belongs. These elements can be thus interpreted by taking into consideration the cultural aspects of his society. Hence, this article surveys the figurative dimensions of his novels and the intention here is mainly to decode the figurative elements such as metaphor, metonymy, hyperbole and other symbolic components of his literary discourse

Learning Optimal and Fair Decision Trees for Non-Discriminative Decision-Making

In recent years, automated data-driven decision-making systems have enjoyed a tremendous success in a variety of fields (e.g., to make product recommendations, or to guide the production of entertainment). More recently, these algorithms are increasingly being used to assist socially sensitive decision-making (e.g., to decide who to admit into a degree program or to prioritize individuals for public housing). Yet, these automated tools may result in discriminative decision-making in the sense that they may treat individuals unfairly or unequally based on membership to a category or a minority, resulting in disparate treatment or disparate impact and violating both moral and ethical standards. This may happen when the training dataset is itself biased (e.g., if individuals belonging to a particular group have historically been discriminated upon). However, it may also happen when the training dataset is unbiased, if the errors made by the system affect individuals belonging to a category or minority differently (e.g., if misclassification rates for Blacks are higher than for Whites). In this paper, we unify the definitions of unfairness across classification and regression. We propose a versatile mixed-integer optimization framework for learning optimal and fair decision trees and variants thereof to prevent disparate treatment and/or disparate impact as appropriate. This translates to a flexible schema for designing fair and interpretable policies suitable for socially sensitive decision-making. We conduct extensive computational studies that show that our framework improves the state-of-the-art in the field (which typically relies on heuristics) to yield non-discriminative decisions at lower cost to overall accuracy.Comment: 33rd AAAI Conference on Artificial Intelligence, 201

Hydroethanolic Allium sativum extract accelerates excision wound healing: evidence for roles of mast-cell infiltration and intracytoplasmic carbohydrate ratio

The present study was designed to evaluate the in vivo effect of Allium sativum (garlic) hydroalcoholic extract on wound healing in rats. For this purpose, 72 mature Wistar rats were divided into four groups (n=18/each) to receive no treatment, placebo, Cicalfate(r), or 2% Allium sativum (AS) extract, administered topically to the wound area, for 21 days. Following the experimental period, tissue samples were dissected out and underwent to histopathological analyses. Fibroblasts, fibrocytes, mast cells, intra-cytoplasmic carbohydrate ratio, neovascularization, collagen deposition, and re-epithelialization were analyzed in all groups. Animals in the treated groups showed significant enhancement in fibroblast, fibrocyte, and mast-cell distribution. Significantly higher neovascularization was observed on day 3 after wound induction in AS-treated animals versus those in the placebo, Cicalfate, and untreated groups (

The Impact of CEO’s Overconfidence on the Relationship between Cash Holdings and Excess

In this study, the impact of CEO’s overconfidence on the relationship between cash holding and excess returns is investigated in companies listed in Tehran Stock Exchange during the years 2011-2018. For CEO’s overconfidence, overinvestment in assets, and for excess returns, the difference between a firm’s stock return and the return of the firm’s benchmark portfolio over the same period is used. By systematic sampling, a sample of 157 companies is selected, and the models have run based on panel data with fixed effects. The results have shown that (1) cash holding has a positive and significant impact on excess returns, (2) CEO’s overconfidence has a negative and significant impact on excess returns, and lastly, (3) CEO’s overconfidence has a negative and significant impact on the relationship between cash holdings and the excess returns. With increasing CEO’s overconfidence, the excess returns will be reduced. Overconfident managers keep cash at a higher level that leads to overinvestment. It consequently decreases excess returns

Capital Structure and Firms Performance in Tehran Stock Exchange

This study investigated the relationship between capital structure and firm performance in firms operating on the Tehran Stock Exchange (TSE). Capital structure was measured by debt leverage. Firm performance was measured using the Tobin’s Q. The sample size was 100 companies operating on the exchange during 2008-2013. The results showed a significant positive relationship between capital structure and firm performance

Selection and Evaluation of the Optimal Marketing Strategy by Using ANP –TOPSIS Approach (Case Study: Emdad Khodro Company of Iran)

Marketing strategy is an integrated set of choices about how we can create and capture value over long periods of time. In other words, a strategy that determines how an organization can reach its marketing objectives; for example, it should focus on which markets and products and how much it should spend on marketing activities. The present study aimed to determine a framework for selecting the best marketing strategy. For determining this framework the decision making techniques of MCDM were used to specify the level of dependency between the factors and the ANP technique was applied to determine the weight of criteria and then TOPSIS technique was used for rankings. The present study that has been conducted at the Emdad Khodro Company of Iran tried to examine the marketing strategies of this company in order to increase the market share of services, develop the network of services and create new business. The findings show that among the strategies of the company, the strategy of creating new business is most important and then the strategies of developing the network of services are in priority. Therefore, the mentioned company should enter new business because the company has partially progressed in the field of developing the network of services and also enjoys a good market share. Also, according to the results of the analysis of network process, it can be said that the most important factors for selecting the best marketing strategy include the innovation capability, managerial capability and quality of services of the discussed company and in order to gain a competitive edge the company can capitalize on them effectively

Obecność przeciwciał przeciw Chlamydia pneumoniae wśród irańskich chorych na stwardnienie rozsiane: badanie pilotażowe

Background and purpose Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system. Genetic and environmental factors could not completely explain the pathogenesis of the disease. Among environmental factors, infectious agents are of more interest than other candidates, so Chlamydia pneumoniae (C. pneumoniae) may have a role in MS development or progression. This study aimed to evaluate C. pneumoniae seropositivity in MS patients. Material and methods Serum samples obtained from a cohort of 85 patients with MS and from 50 age- and sex-matched controls were assessed for the presence of antibodies. IgM and IgG concentration for C. pneumoniae were determined with enzyme-linked immunosorbent assay (ELISA). Results The mean age was 33.8 (9.96) years in the MS group and 33.9 (10.7) years in controls. Female/male ratio was 3.5 : 1 in the MS group; 69 patients (81%) had relapsing-remitting course (RRMS) and 16 patients (19%) had secondary progressive course (SPMS). The median concentration of C. pneumoniae IgM in the MS group was 0.5 RU/mL (0.25–1) versus 0.5 RU/mL (0.3–0.8) in the control group (p = 0.66); likewise, the median concentration of C. pneumoniae IgG in MS patients was 57.3 RU/mL (17.05–95.1) compared with 56.15 RU/mL (6.85–102.5) in the control group (p = 0.85). Regarding the clinical course, C. pneumoniae IgG was 55.1 RU/mL (20.7–88.6) in RRMS and 59.1 RU/mL (5.35–112) in SPMS (p = 0.8). Conclusion No association was observed between MS and C. pneumoniae in Iranian MS patients.Wstęp i cel pracy Stwardnienie rozsiane (SR) jest przewlekłą zapalną chorobą autoimmunologiczną ośrodkowego układu nerwowego. Czynniki genetyczne i środowiskowe nie tłumaczą w pełni patogenezy choroby. Wśród czynników środowiskowych szczególne zainteresowanie budzą drobnoustroje powodujące zakażenia. Chlamydia pneumoniae (C. pneumoniae) mogłaby odgrywać rolę w powstawaniu lub postępie SR. Celem badania była ocena obecności przeciwciał przeciwko C. pneumoniae w surowicy chorych na SR. Materiał i metody Od 85 chorych na SR i od 50 osób z grupy kontrolnej, dobranych pod względem wieku i płci, pobrano krew i za pomocą testów immunoenzymatycznych (ELISA) zbadano stężenia IgM i IgG przeciwko C. pneumoniae w surowicy. Wyniki Średnia wieku wyniosła 33,8 (9,96) roku w grupie chorych na SR i 33,9 (10,7) roku w grupie kontrolnej. W grupie chorych na SR proporcja kobiet do mężczyzn wyniosła 3,5 : 1. U 69 pacjentów (81%) choroba miała przebieg nawracająco-zwalniający, a u 16 pacjentów (19%) – wtórnie postępujący. Mediana stężenia IgM przeciwko C. pneumoniae wyniosła 0,5 RU/ml (0,25–1) w grupie chorych na SR w porównaniu z 0,5 RU/ml (0,3–0,8) w grupie kontrolnej (p = 0,66). Mediana stężenia IgG przeciwko C. pneumoniae wyniosła 57,3 RU/ml (17,05–95,1) w grupie chorych na SR w porównaniu z 56,15 RU/ml (6,85–102,5) w grupie kontrolnej (p = 0,85). Mediana stężenia IgG przeciwko C. pneumoniae wśród chorych na nawracająco-zwalniające SR wyniosła 55,1 RU/ml (20,7–88,6), a w grupie chorych z postacią wtórnie postępującą choroby − 59,1 RU/ml (5,35–112) (p = 0,8). Wnioski Wśród irańskich chorych na SR nie stwierdzono związku między SR a występowaniem przeciwciał przeciwko C. pneumoniae