Indefinite causal order enables perfect quantum communication with zero capacity channel

Quantum mechanics is compatible with scenarios where the relative order between two events is indefinite. Here we show that two instances of a noisy process, used in a superposition of two alternative orders, can behave as a perfect quantum communication channel. This phenomenon occurs even if the original processes have zero capacity to transmit quantum information. In contrast, perfect quantum communication does not occur when the message is sent along a superposition of paths, with independent noise processes acting on each path. The possibility of perfect quantum communication through noisy channels highlights a fundamental difference between the superposition of orders in time and the superposition of paths in space.Comment: 5+9 pages (minor modifications

Local Inaccessibility of Random Classical Information : Conditional Nonlocality demands Entanglement

Discrimination of quantum states under local operations and classical communication (LOCC) is an intriguing question in the context of local retrieval of classical information, encoded in the multipartite quantum systems. All the local quantum state discrimination premises, considered so far, mimic a basic communication set-up, where the spatially separated decoding devices are independent of any additional input. Here, exploring a generalized communication scenario we introduce a framework for input-dependent local quantum state discrimination, which we call local random authentication (LRA). Referring to the term nonlocality, often used to indicate the impossibility of local state discrimination, we coin the term conditional nonlocality for the impossibility associated with the task LRA. We report that conditional nonlocality necessitates the presence of entangled states in the ensemble, a feature absent from erstwhile nonlocality arguments based on local state discrimination. Conversely, all the states in a complete basis set being entangled implies conditional nonlocality. However, the impossibility of LRA also exhibits more conditional nonlocality with less entanglement. The relation between the possibility of LRA and local state discrimination for sets of multipartite quantum states, both in the perfect and conclusive cases, has also been established. The results highlight a completely new aspect of the interplay between the security of information in a network and quantum entanglement under the LOCC paradigm.Comment: An appropriate example for Proposition 2 is added and the details of which is supplemented in the Appendi

Gastric adenocarcinoma in a patient re-infected with H. pylori after regression of MALT lymphoma with successful anti-H. pylori therapy and gastric resection: a case report

BACKGROUND: Helicobacter pylori (H. pylori) has been etiologically linked with primary gastric lymphoma (PGL) and gastric carcinoma (GC). There are a few reports of occurrence of both diseases in the same patient with H. pylori infection. CASE PRESENTATION: We report a patient with PGL in whom the tumor regressed after surgical resection combined with eradication of H. pylori infection. However, he developed GC on follow up; this was temporally associated with recrudescence / re-infection of H. pylori. This is perhaps first report of such occurrence. CONCLUSIONS: Possible cause and effect relationship between H. pylori infection and both PGL and GC is discussed. This case also documents a unique problem in management of PGL in tropical countries where re-infection with H. pylori is supposed to be high

Effectiveness of Need-Based Teacher’s Training Program to Enhance Online Teaching Quality

The COVID-19 pandemic drastically transformed the global education system forever. To sustain the education system, e-learning has been adopted as an alternative teaching-learning strategy in most countries. Due to this sudden transition, teachers had practically no time to prepare themselves for distance learning, especially in developing countries. Consequently, teachers faced numerous challenges while teaching online. The present study aimed to explore the effectiveness of need-based teachers’ training programs to address online teaching challenges faced by primary and secondary level teachers. Adopting a mixed-method research approach, this study was conducted between January and July 2021 at 6 primary and secondary level institutions in 4 different districts of Bangladesh. Primary data were collected through face-to-face surveys, electronic surveys, and one-to-one semi-structured interviews. Descriptive analysis and bivariate correlational analysis were carried out for quantitative data exploration. On the other hand, qualitative data were coded and analyzed thematically. Findings highlight that less familiarity with online teaching tools, lack of digital skills, unstable Internet connectivity, difficulties with time management, insufficient teaching materials, lack of satisfaction, heavy workload, and poor self-confidence were the key barriers to online teaching. However, in this study, a proper need-based teacher training program is found to be considerably effective in improving online teaching quality by increasing teachers’ technological skills, confidence, satisfaction, motivation, time management skill, and behavioral changes. The overall findings of this study are expected to assist the devolved authorities in implementing synchronized policies to improve online teaching quality

Identifying Mathematics Anxiety Through Automated Process (IMATAP): A Web-Based Screening Tool for Teachers

Mathematics anxiety (MA) is considered a potential barrier to success in science, technology, engineering, and mathematics (STEM) careers. A good number of students around the globe are terrified of mathematics. They do whatever they can to avoid math or math-related subjects. Therefore, the early identification of MA and its underlying factors is crucial in initiating timely interventions that can enhance positive attitudes in math, boost math performance, minimize math avoidance, and motivate students to pursue math-related careers. In this paper, we have presented a unique, multifaceted, and complete web-based MA screening tool called identifying mathematics anxiety through an automated process (IMATAP) to assess MA, its severity, and its deficiency. This assessment provides a detailed explanation of developing MA and helps teachers, parents, educators, and researchers design need-based intervention techniques (personalized or cluster-based) to reduce MA, which will ultimately help math-anxious students overcome math fear. Over the past two years (2021–2022), IMATAP has been successfully implemented in nine different primary and secondary level institutions in Bangladesh. Findings revealed that the effectiveness of the IMATAP system has been appreciated and highly accepted by both students and teachers