Quantum repeaters based on individual electron spins and nuclear-spin-ensemble memories in quantum dots

Inspired by recent developments in the control and manipulation of quantum dot nuclear spins, which allow for the transfer of an electron spin state to the surrounding nuclear-spin ensemble for storage, we propose a quantum repeater scheme that combines individual quantum dot electron spins and nuclear-spin ensembles, which serve as spin-photon interfaces and quantum memories respectively. We consider the use of low-strain quantum dots embedded in high-cooperativity optical microcavities. Quantum dot nuclear-spin ensembles allow for the long-term storage of entangled states, and heralded entanglement swapping is performed using cavity-assisted gates. We highlight the advances in quantum dot technologies required to realize our quantum repeater scheme which promises the establishment of high-fidelity entanglement over long distances with a distribution rate exceeding that of the direct transmission of photons.Comment: 21 pages, 5 figure

Quantum Optical Memory for Entanglement Distribution

Optical photons are powerful carriers of quantum information, which can be delivered in free space by satellites or in fibers on the ground over long distances. Entanglement of quantum states over long distances can empower quantum computing, quantum communications, and quantum sensing. Quantum optical memories can effectively store and manipulate quantum states, which makes them indispensable elements in future long-distance quantum networks. Over the past two decades, quantum optical memories with high fidelity, high efficiencies, long storage times, and promising multiplexing capabilities have been developed, especially at the single photon level. In this review, we introduce the working principles of commonly used quantum memory protocols and summarize the recent advances in quantum memory demonstrations. We also offer a vision for future quantum optical memory devices that may enable entanglement distribution over long distances

The Role of Empowering Leadership Dimensions of School Principals in the Psychological Ownership of Teachers

Introduction:In the last two decades, empowerment practices have gained recognition as effective approaches for organizations to enhance positive work outcomes by fostering employees' sense of competence, self-determination, meaningfulness, and influence (Maynard et al., 2014). Empowerment theory suggests that leaders play a crucial role in empowering employees (Maynard et al., 2012). Leaders have the ability to create an environment conducive to employees taking ownership of their tasks and surroundings (Stander & Coxen, 2017). Consequently, organizations must establish environments that enable individuals to maximize their potential and contribute value to the organization (Stander & Rothmann, 2009). Employees require leaders, who understand the importance of ownership and empowerment for their emotional and intellectual growth (Bhatnagar, 2005). Several studies have highlighted the significant role of work in psychological ownership, including research by Kim & Beehr (2018) and Knapp et al. (2014). Studies by Su & Ng (2019) and Yıldız et al. (2015) have explored the impact of participation in decision-making on psychological ownership. Additionally, Olckers & Enslin (2016) have demonstrated the role of trust in fostering psychological ownership, while Cheng et al. (2021) and Yıldız et al. (2015) have examined the influence of providing independence on psychological ownership. These studies indicate that empowering leadership behaviors are associated with followers' psychological ownership. Therefore, the present research aimed to investigate the role of empowering leadership dimensions exhibited by school principals in teachers' psychological ownership. Specifically, we sought to determine whether the empowering leadership dimensions of school principals significantly impacted teachers' psychological ownership and identify which dimensions had the greatest and least significant effects on psychological ownership.  Materials & MethodsThe present study adopted a quantitative research approach, aligning with the research philosophy and the applied nature of the study. In terms of data collection and analysis, a descriptive method was employed, specifically utilizing correlation studies and structural equation modeling. The research population comprised all primary school teachers in Qorve City, totaling 548 individuals (350 women and 198 men). A sample of 225 participants (144 women and 81 men) was selected by using proportional stratified random sampling based on Morgan's table. The research methodology employed was correlation analysis.Discussion of Results & ConclusionThe findings of the current study indicated that the dimensions of empowering leadership exhibited by the school principals had a significant and positive impact on the teachers' psychological ownership. The effects of these dimensions ranged from 0.13 to 0.24, with participation in decision-making and significance having the greatest and least effects, respectively. Collectively, the 4 dimensions of empowering leadership could explain 33% of the variance in the teachers' psychological ownership. The Importance-Performance Matrix Analysis (IPMA) conducted to determine the relative importance of the structures in the structural model revealed that all the four dimensions of empowering leadership exhibited high importance and high performance, falling within the consolidation area. Based on these findings, several suggestions were proposed to strengthen the effects of the empowering leadership dimensions of school principals on teachers' psychological ownership:1) Clarifying the role of teachers in societal growth and development, emphasizing their impact on the society2) Providing necessary support and resources to enhance teachers' professional development3) Fostering a safe and supportive environment in schools that encourages teachers to express their opinions on school-related matters4) Empowering teachers with collaborative decision-making skills5) Encouraging participation through the establishment of quality circles within the school6) Analyzing the fit between teachers and their assigned tasks7) Clearly defining the levels of independence and authority teachers have in their assigned tasks8) Gradually delegating authority to teachers in solving school problems9) Promoting transparency and honesty in the speech and actions of school principals10) Institutionalizing a culture of positive and developmental responsibility within the schoolIt could be concluded that the creation, growth, and strengthening of teachers' psychological ownership were influenced by the school principals and their leadership. Therefore, the active application of empowering leadership with a focus on its dimensions could have positive effects on teachers' psychological ownership. To collect data, the researchers utilized the enabling leadership questionnaires developed by Ahearne et al. (2005) and the psychological ownership questionnaire developed by Olckers (2011). The descriptive analysis involved the use of frequency distribution tables, mean, and standard deviation. To test the research hypotheses, statistical techniques, such as the Pearson correlation matrix and structural equation modeling, were employed using the statistical software of SPSSv.25 and LISRELv.10.30. Additionally, the relative importance of the structures in the model was determined through the use of an IPMA

Effects of vitamin B6 on premenstrual syndrome: A systematic review and meta-Analysis

Background and Objective: Premenstrual syndrome (PMS) refers to a range of physical and psychological symptoms which regularly occur during the luteal phase of a menstrual cycle and disappear short after menstruation starts. Considering the negative effects of PMS on women's daily life, various treatments have been developed to alleviate its symptoms. Vitamin B6 is one of the complementary therapies used to treat PMS. The present meta-Analysis aimed to investigate the effects of vitamin B6 on PMS. Methodology: Different databases including PubMed, ISI, Scopus, SID, Magiran, Science Direct, and Medlib were searched to identify studies addressing the effects of vitamin B6 on PMS. The relevant data obtained from these papers were analyzed by a random-effects model. Data were analyzed using R Ver. 3.2.3 Software and STATA. Results: There were significant reductions in the mean scores of PMS after treatment with vitamin B6 compare to control groups. Moreover, the mean PMS scores of the two groups were also significantly different after the treatment. The mean difference between the two groups was -1.19 [95% CI: -1.94,-0.44; P = 0.002]. Significant reductions were also observed in physical symptoms (P = 0.006) and psychological symptoms (P < 0.001) of PMS after the intervention. Conclusion: The results of our meta-Analysis confirmed vitamin B6 as a beneficial, inexpensive, and effective treatment for PMS symptoms. Therefore, the administration of this treatment option will enable midwives to achieve the important goal of reducing PMS symptoms

Long-distance quantum communication with single solid-state spins

Long-distance transfer of quantum information is an essential ability for many applications of quantum science. A natural choice to distribute quantum information is to encode it into photons and transfer it through optical fibers. However, due to the unavoidable transmission losses present in every communication channel, the distances for efficient quantum communication via direct-state transfer are limited to a few hundred kilometers. To overcome this limitation, the use of quantum repeaters has been suggested. A quantum repeater protocol aims to establish entanglement (i.e., quantum correlation) between remote nodes by first generating entanglement over shorter distance pieces, storing it in quantum memories, and finally extending it to the whole distance using entanglement swapping. The main goal of this thesis is to design quantum repeater architectures using single solid-state quantum emitters and to develop the two-qubit gates required for performing entanglement swapping. We first explain the basic ideas of quantum repeaters and introduce potential material candidates, single erbium (168Er) and europium (151Eu) ions doped yttrium orthosilicate photonic crystals. Next, we propose a quantum repeater scheme combing erbium and europium ions to generate and distribute entanglement over long distances. We study the entanglement generation rate of the protocol and compare it with the rate of a well-known ensemble-based quantum repeater. Then, using cavity assisted interactions, we propose three different schemes to perform high fidelity two-qubit gates between single quantum systems. We quantify their expected performance in detail by taking into account many realistic imperfections and compare their strengths and weaknesses. The ability to perform local two-qubits gates is especially crucial in terms of distributing entanglement. Finally, based on our gained knowledge through these projects, we propose our second quantum repeater architecture based on erbium (167Er) ions, which outperforms the first scheme. We study two possibilities for distributing entanglement and calculate the overall fidelity as well as the distribution rate of the protocol

Validity and Reliability of the Persian Version of the Dysphagia Handicap Index (DHI)

Introduction: The Dysphagia Handicap Index (DHI) is one of the instruments used for measuring a dysphagic patient’s self-assessment. In some ways, it reflects the patient’s quality of life. Although it has been recognized and widely applied in English speaking populations, it has not been used in its present forms in Persian speaking countries. The purpose of this study was to adapt a Persian version of the DHI and to evaluate its validity, consistency, and reliability in the Persian population with oropharyngeal dysphagia.   Materials and Methods: Some stages for cross-cultural adaptation were performed, which consisted in translation, synthesis, back translation, review by an expert committee, and final proof reading. The generated Persian DHI was administered to 85 patients with oropharyngeal dysphagia and 89 control subjects at Zahedan city between May 2013 and August 2013. The patients and control subjects answered the same questionnaire 2 weeks later to verify the test-retest reliability. Internal consistency and test-retest reliability were evaluated. The results of the patients and the control group were compared.   Results: The Persian DHI showed good internal consistency (Cronbach’s alpha coefficients range from 0.82 to 0.94). Also, good test-retest reliability was found for the total scores of the Persian DHI (r=0.89). There was a significant difference between the DHI scores of the control group and those of the oropharyngeal dysphagia group (P‹0.001).   Conclusion:  The Persian version of the DHI achieved Face and translation validity. This study demonstrated that the Persian DHI is a valid tool for self-assessment of the handicapping effects of dysphagia on the physical, functional, and emotional aspects of patient life and can be a useful tool for screening and treatment planning for the Persian-speaking dysphagic patients, regardless of the cause or the severity of the dysphagia

Proposal for transduction between microwave and optical photons using 167Er\mathrm{^{167}Er}-doped yttrium orthosilicate

Efficient transduction devices that reversibly convert optical and microwave quantum signals into each other are essential for integrating different technologies. Rare-earth ions in solids, and in particular Erbium ions, with both optical and microwave addressable transitions are promising candidates for designing transducers. We propose a microwave-to-optical quantum transducer scheme based on the dark state protocol in $\mathrm{^{167}Er}$ doped into yttrium orthosilicate (YSO) at zero external magnetic fields. Zero-field operation is beneficial for superconducting resonators that can incur extra losses in magnetic fields. By calculating the fidelity and efficiency of the transducer, considering the most important imperfections, we show that an efficient conversion is possible with a high fidelity. We also investigate the microwave transitions of $\mathrm{^{167}Er}$:YSO that can be used for the transducer protocol.Comment: 8 pages, 5 figure