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Bell nonlocality as a resource for device-independent certification schemes has been studied extensively in recent years. The strongest form of device-independent certification is referred to as self-testing, which given a device, certifies the promised quantum state as well as quantum measurements performed on it without any knowledge of the internal workings of the device. In spite of various results on self-testing protocols, it remains a highly nontrivial problem to propose a certification scheme of qudit–qudit entangled states based on violation of a single d-outcome Bell inequality. Here we address this problem and propose a self-testing protocol for the maximally entangled state of any local dimension using the minimum number of measurements possible, i.e., two per subsystem. Our self-testing result can be used to establish unbounded randomness expansion, log2d perfect random bits, while it requires only one random bit to encode the measurement choice.

Although 'quantum contextuality' is one of the most fundamental non-classical feature, its generic role in information processing and computation is an open quest. In this article, we present a family of distributed computing tasks pertaining to every logical proof of Kochen-Specker (KS) contextuality in two different one-way communication scenarios: (I) communication of bounded dimensional system, (II) communication of unbounded dimensional system while keeping certain information oblivious, namely, oblivious communication (OC). As the later remains largely unexplored, we introduce a general framework for OC tasks and provide a methodology for obtaining an upper bound on the success of OC tasks in classical communication. We show that quantum communication comprised of every KS set of vectors outperforms classical communication and perfectly accomplish the task in both the aforementioned scenarios. We explicitly discuss the communication tasks pertaining to the simplest state independent contextuality sets of dimension three and four. Our results establish an operational significance to single system contextuality and open up the possibility of semi-device independent quantum information processing based on that. Alongside, we identify any advantage in OC tasks as a witness of preparation contextuality.

Bell nonlocality—the existence of quantum correlations that cannot be explained by classical means—is certainly one of the most striking features of quantum mechanics. Its range of applications in device-independent protocols is constantly growing. Many relevant quantum features can be inferred from violations of Bell inequalities, including entanglement detection and quantification, and state certification applicable to systems of arbitrary number of particles. A complete characterisation of nonlocal correlations for many-body systems is, however, a computationally intractable problem. Even if one restricts the analysis to specific classes of states, no general method to tailor Bell inequalities to be violated by a given state is known. In this work we provide a general construction of Bell expressions tailored to the graph states of any prime local dimension. These form a broad class of multipartite quantum states that have many applications in quantum information, including quantum error correction. We analytically determine their maximal quantum values, a number of high relevance for device-independent applications of Bell inequalities. Importantly, the number of expectation values to determine in order to test the violation of our inequalities scales only linearly with the system size, which we expect to be the optimal scaling one can hope for in this case. Finally, we show that these inequalities can be used for self-testing of multi-qutrit graph states such as the well-known four-qutrit absolutely maximally entangled state AME(4,3).

Distinguishing physical processes is one of the fundamental problems in quantum physics. Although distinguishability of quantum preparations and quantum channels have been studied considerably, distinguishability of quantum measurements remains largely unexplored. We investigate the problem of single-shot discrimination of quantum measurements using two strategies, one based on single quantum systems and the other one based on entangled quantum systems. First, we formally define both scenarios. We then construct sets of measurements (including non-projective) in arbitrary finite dimensions that are perfectly distinguishable within the second scenario using quantum entanglement, while not in the one based on single quantum systems. Furthermore, we show that any advantage in measurement discrimination tasks over single systems is a demonstration of Einstein–Podolsky–Rosen ‘quantum steering’. Alongside, we prove that all pure two-qubit entangled states provide an advantage in a measurement discrimination task over one-qubit systems.

Sovereign default risk (SDR) is a critical concern for emerging markets like Bangladesh, given its potential impact on economic stability. This study examines how key macroeconomic indicators—remittances, fiscal deficits, GDP, foreign reserves, external debt, and the remittance-to-GDP ratio—affect Bangladesh's sovereign default risk from 2000 to 2024. The study fills a gap in existing literature by integrating the Balance of Payments Theory and Sovereign Risk Theory to create a comprehensive framework for analyzing SDR in Bangladesh. Using robust regression techniques, including Huber and Ridge regression, the research explores the relationships between these variables and Bangladesh's sovereign creditworthiness. The findings reveal that foreign reserves significantly reduce SDR, while remittances have a marginally positive effect, suggesting that over-reliance on remittances may increase sovereign risk. Fiscal deficit, GDP, and external debt, however, did not show significant effects, highlighting the complex nature of these relationships. The study emphasizes the importance of strengthening foreign reserves, diversifying economic sources, and managing fiscal discipline to reduce sovereign default risk. Policymakers can leverage these insights to enhance economic resilience and improve financial stability. This research contributes to the understanding of sovereign default risk by highlighting the role of reserves in mitigating risks and provides practical policy recommendations for Bangladesh's financial sustainability.

The global market uptake of the fourth generation-Long-Term Evolution (4G-LTE) Mobile Broadband (MoBro) services are steadily rising, leading to higher capital investments by mobile network operators (MNOs) to scale-up their infrastructure for meeting the impending demand for MoBro data the world over. However, MNOs face uncertainties about financial returns from such investments, owing to a host of technological and market-related factors, which impact the enablement of such 4G-LTE MoBro services. These challenges are clearly evident in the Indian market. Firstly, 4G-LTE subscribers in the rural India contribute to less than one-third of the overall market size. Secondly, India performs poorly in terms of minimum capacity requirements of the 4G-LTE MoBro services. Thirdly, the rise in per-user consumption of MoBro data does not translate into a similar rise in the MNOs’ revenue. Fourthly, the socio-economic-geographic segregation of India into twenty-two administrative zones (referred to as telecom circles) add to the complexities in the capital investment decisions of MNOs. To address the above challenges, we model various cost and profitability scenarios of a hypothetical MNO providing universal 4G-LTE deployment across the twenty-two telecom circles in India using the available spectrum bands. Our proposed model is firmly established in the “network investment economics” framework for telecom innovations. We adopt a technology diffusion-based approach to forecast the 4G-LTE subscribers in India. We focus on the requirements of 4G-LTE MoBro infrastructure investments, including the spectrum selection decisions by MNOs, and show that, for valuation of the spectrum, the policymakers in India need to take into account the potential of the spectrum in terms of financial returns to an MNO deploying 4G-LTE using that spectrum, as against merely valuing the spectrum based on primarily the technical characteristics of its carrier frequency and benchmarks of prior spectrum auction prices in a particular telecom circle. Finally, we also show that a nationwide 4G-LTE network, which is universal, inclusive, and adhering to the global standards in terms of service quality, can be financially lucrative for MNOs, if enabled by appropriate policies instituting collaborative frameworks for infrastructure sharing, and price rationalization of spectrum bands across the twenty-two telecom circles.

We have calculated one-loop amplitudes for the production of Higgs boson in association with two electroweak bosons (H, γ, Z) via gluon-gluon fusion. We present preliminary results for the total cross section at 8, 13 and 100 TeV center-of-mass energies at pp colliders. We study the interference effect and, also comment on the effect of new physics in terms of anomalous couplings of the Higgs boson in these processes.

Globally, Mobile Network Operators (MNOs) incur considerable capital investments towards the acquisition of spectrum, deployment of mobile networks, and marketing and advertising of their mobile services to potential mobile subscribers. The extant literature, which is mainly conceptual, suggests that such capital investments impact the individual mobile subscriber base of MNOs. However, the extant literature lacks in quantitative explanation of such impacts. We address this lacuna by proposing an empirical framework using a novel panel dataset of the four largest MNOs of India, during the years 2009–2017. We find that capital investments in the spectrum (both contemporaneous and lagged) and mobile networks (lagged) positively impact the mobile subscriber base of MNOs in India. We observe that a “triggering effect,” such as the market rollout of 4G (fourth generation) services, leads to an initial slump in the mobile subscriber base of MNOs, which is counterintuitive and signifies the importance of early network-preparedness on the part of MNOs. We also find that, in the event of the aforementioned market triggers, MNOs’ firm-size and potential to invest in the spectrum, in addition to network-preparedness, are crucial for its survival.

Purpose This paper aims to investigate the relationship of female participation in labor force with the cybersecurity maturity of nations and the enabling role of e-government development in moderating the same. Design/methodology/approach The authors have conducted fixed-effects regression using archival data for 149 countries taken from secondary sources. Furthermore, the authors have grouped the sample countries into four levels of cybersecurity maturity (unprepared, reactive, anticipatory and innovative) using clustering techniques, and studied the influence of their interest variables for individual groups. Findings Results show that female participation in labor force positively influences national cybersecurity maturity, and e-government development positively moderates the said relationship, thereby enabling the empowerment of women. Practical implications Encouraging broader participation of women in the labor force and prioritizing investments in e-government development are essential steps that organizations and governments may take to enhance a country’s cybersecurity maturity level. Originality/value This study empirically demonstrates the impact of the nuanced interplay between female participation in labor force and the e-government development of a nation on its cybersecurity maturity.

As wireless users have become increasingly mobile, tracking their location and establishing communications links between them has become critical. Location management, paging, and routing are the key technologies for performing these crucial functions. This comprehensive book covers past, present, and future advances in location management and routing protocols for both single-hop and multi-hop mobile wireless networks. It provides you with an in-depth examination of mobility, location management, paging, and radio resources for cellular networks, and it focuses on routing protocols and medium access control techniques for mobile ad hoc networks. Key topics discussed in detail include mobility models and traces, radio resource management, blanket and intelligent paging, location updating, location area planning, medium access control techniques, and unicast and multicast routing, as well as routing in next generation wireless and pervasive networks.