Unitary Systems Research Articles

Energetic cost as a consequence of parallel transporting speed limit

Time-optimal unitary operating quantum systems and energy-efficient quantum gates are vital in quantum engineering. Here, we establish the connection between the energetic cost and the quantum speed limit for parallel evolving of a quantum system. Our results show that the energetic cost is the consequence of parallel transporting speed limit, which opens up the critical role of parallel transport of the quantum state for the quantum technologies such as the quantum simulation, the quantum information processing. Our investigations present a route to construct the energetic-efficient quantum gate. In addition, our theoretical framework provides an alternative method for calculating quantum speed limit. Two typical relevant systems are employed to illustrate our results: the spin-1/2 particle in the rotating magnetic field and the entanglement swap gate.

Corrections to Diffusion in Interacting Quantum Systems

The approach to equilibrium in interacting classical and quantum systems is a challenging problem of both theoretical and experimental interest. One useful organizing principle characterizing equilibration is the dissipative universality class, the most prevalent one being diffusion. In this paper, we use the effective field theory (EFT) of diffusion to systematically obtain universal power-law corrections to diffusion. We then employ large-scale simulations of classical and quantum systems to explore their validity. In particular, we find universal scaling functions for the corrections to the dynamical structure factor ⟨n(x,t)n⟩, in the presence of a single U(1) or SU(2) charge in systems with and without particle-hole symmetry, and present the framework to generalize the calculation to multiple charges. Classical simulations show remarkable agreement with EFT predictions for subleading corrections, pushing precision tests of effective theories for thermalizing systems to an unprecedented level. Moving to quantum systems, we perform large-scale tensor-network simulations in unitary and noisy 1D Floquet systems with conserved magnetization. We find a qualitative agreement with EFT, which becomes quantitative in the case of noisy systems. Additionally, we show how the knowledge of EFT corrections allows for fitting methods, which can improve the estimation of transport parameters at the intermediate times accessible by simulations and experiments. Finally, we explore nonlinear response in quantum systems and find that EFT provides an accurate prediction for its behavior. Our results provide a basis for a better understanding of the nonlinear phenomena present in thermalizing systems. Published by the American Physical Society 2024

A Brief Overview of Some Federal Systems and Restructuring in Nepal

Modern politics endorses various governing systems, with the unitary and federal systems being the primary forms. These systems can change in response to the immediate needs of a country, influenced by the will of the people and the interests of leadership. Some unitary states have transitioned to federal systems, while some federal systems have disintegrated, depending on the circumstances and necessities of the state. In the context of conflict management, Nepal has transitioned from a unitary system to federalism through state restructuring. The primary reason for this shift was the internal conflict within the state. This article focuses on the federalism adopted by Nepal, examining the experiences of major federal countries worldwide and discussing Nepal's approach to federalism. The study attempts to address and find solutions to several pertinent questions regarding this transition.

ROLE OF INDIAN CONSTITUTION IN WOMEN EMPOWERMENT

The Indian Constitution is a beautiful blend of both federal and unitary systems. The Indian Constitution is called a federal constitution on the basis that it is a written constitution. It provides for a supreme and independent judiciary. The preamble of the Indian Constitution declares the goal of making India a democratic republic. Its head of state will be elected democratically. Being a republic means that any common person of India, whether a man or a woman, can reach the highest position in the country on the basis of his qualifications. India is a union of states. It is an independent sovereign socialist democratic republic with a parliamentary system of government. This republic is governed according to the Constitution of India which was adopted by the Constituent Assembly on 26 November 1949 and which came into force on 26 January 1950. The Constitution of India is the supreme legal authority that links together the legislative, executive and judicial organs of the government. The Constitution provides fundamental rights to all citizens and gives the independent judiciary the right to declare invalid the laws or government actions that violate the Constitution. In the Vedic period, women had a very respectable position in India. But later in the medieval period, the status of women deteriorated a lot due to the arrival of foreigners. Due to illiteracy, bad customs and conservatism in the society, the status of women was greatly affected. But gradually in the first half of the nineteenth century, some social workers of India like Raja Ram Mahen Rai, Swami Dayanand Saraswati, Ishwarchand Vidyasagar and Keshavchand Sen raised their voice against the oppressive social system. They raised their voice before the then British rulers for gender equality, women education, ban on Sati Pratha and ban on polygamy, as a result of which Sati Pratha Prohibition Act, 1829 and Hindu Widow Remarriage Act in 1856, Age of Constancy Bill in 1891 and Vative Marriage Act to stop polygamy were passed. By the twenty-first century, the condition of women started improving and the Indian Constitution implemented provisions to promote women's upliftment and empowerment and to improve their economic, social, educational and political status and to include them in the mainstream of development by running many welfare schemes and developmental works.

Federalism, centrism, and the crisis of the Nigerian academy

ABSTRACT The article focuses on the crisis of the academy in Nigerian federalism. It begins by departing from the literature that conceptualizes the crisis of African universities in terms of state incorporation of the academy. The article draws attention to the necessity of differentiating federal polities from unitary systems and presents federations as being distinct for their assignment of university education competence to make for jurisdictional pluralism. Drawing on the fiscal and comparative federalism literatures, it traces the crisis of the academy partly to federal erasure of jurisdictional authority of the states, and partly to a fiscal regime of distributive revenue pool and the associated lack of consequences for opportunistic behaviour. It shows that the erasure of jurisdictional pluralism exposes the entire university system to adverse developments at the centre. It also shows that opportunistic behaviour weakens public institutions and undermines the capacity of the universities to deliver services.

Aging and adsorption behavior of PP-MPs for methylene blue and tetracycline in unitary and binary systems

The omnipresence of microplastics (MPs) around the world has attracted extensive attention in the past decade with more focuses on the interactions of standard MPs without additives in regular shapes and individual pollutant, whereas the actual MPs containing various additives in irregular shapes and complex pollutants are often co-occurrence in the environments. In this paper, the adsorption performance of disposable polypropylene (PP) cups-based MPs subjected to ultraviolet irradiation was investigated in unitary and binary water matrices. The surface characteristics were analyzed and the experimental data of adsorption were fitted by various kinetic and isotherm models, and the results indicated that more cracks and oxygen-containing functional groups with decreased hydrophobicity were produced with aging, and electrostatic attraction and hydrogen bonding dominated methylene blue (MB) and tetracycline (TC) capture in the individual system. Moreover, pseudo-second order kinetic model better described the adsorption processes. In the binary system, the co-existence of TC promoted MB uptake, while the presence of MB inhibited TC capture. In addition, TC adsorption was enhanced by Ca2+, maybe due to its complexation effect, while the presence of mono- and divalent inorganic salts inhibited MB capture. This research provides useful insights for the fate of PP-MPs and organic pollutants in the complex environments.

Features, Paradoxes and Amendments of Perturbative Non-Hermitian Quantum Mechanics

Quantum mechanics of unitary systems is considered in quasi-Hermitian representation and in the dynamical regime in which one has to take into account the ubiquitous presence of perturbations, random or specific. In this paper, it is shown that multiple technical obstacles encountered in such a context can be circumvented via just a mild amendment of the so-called Rayleigh–Schrödinger perturbation–expansion approach. In particular, the quasi-Hermitian formalism characterized by an enhancement of flexibility is shown to remain mathematically tractable while, on the phenomenological side, opening several new model-building horizons. It is emphasized that they include, i.a., the study of generic random perturbations and/or of multiple specific non-Hermitian toy models. In parallel, several paradoxes and open questions are shown to survive.

Resonance triplet dynamics in the quenched unitary Bose gas

The quenched unitary Bose gas is a paradigmatic example of a strongly interacting out-of-equilibrium quantum system, whose dynamics become difficult to describe theoretically due to the growth of non-Gaussian quantum correlations. We develop a conserving many-body theory capable of capturing these effects, allowing us to model the postquench dynamics in the previously inaccessible time regime where the gas departs from the universal prethermal stage. Our results show that this departure is driven by the growth of strong lossless three-body correlations, rather than atomic losses, thus framing the heating of the gas in this regime as a fully coherent phenomenon. We uncover the specific few-body scattering processes that affect this heating and show that the expected connection between the two-body and three-body contacts and the tail of the momentum distribution is obscured following the prethermal stage, explaining the absence of this connection in experiments. Our general framework, which reframes the dynamics of unitary quantum systems in terms of explicit connections to microscopic physics, can be broadly applied to any quantum system containing strong few-body correlations. Published by the American Physical Society 2024

Optimizing thermosolutal and hydrothermal performance of radiative hybrid ferrofluid and entropy generation in a wavy porous enclosure

This research conducts a comprehensive investigation to enhance the thermosolutal and hydrothermal efficiency of a radiative Fe3O4–Cu–H2O hybrid ferrofluid within a wavy porous enclosure with the enlightenment for heat transfer and material science. The primary focus is on optimizing the thermosolutal performance in this irregular enclosure in which the lower boundary undergoes non-uniform heating and concentration, and the curved lateral boundaries keep cooling, lower concentration. Simultaneously, the upper flat boundary remains adiabatic. Using an efficient Higher Order Compact (HOC) scheme, we solve the governing streamfunction (ψ)-vorticity (ζ) form with the incorporation of energy and species transport equations of the coupled Navier–Stokes equations. Our results are robust and validated against established experimental and numerical data sources. The investigation delves into the impacts of well-defined parameters such as Rayleigh number (Ra), Hartmann number (Ha), Darcy number (Da), Buoyancy ratio (N), Lewis number (Le), Radiation parameter (Rd), shape factor of nanoparticles (m) and solid volume fraction (ϕhnp) of the hybrid ferrofluid. Key findings underscore the consistent enhancement of both average Nusselt number (Nu¯) and average Sherwood number (Sh¯) with higher Buoyancy Ratio Numbers (N). Blades-shaped nanoparticles (m=8.6) demonstrate superior performance in both unitary and hybrid ferrofluid systems. Optimal conditions, identified at ϕhnp=0.04 and Ra=104 by the Bejan number (Be), underscore the positive impact of higher Buoyancy Ratio Numbers (N), resulting in a 25.41% increase in Nu¯ and an impressive 43.81% boost in Sh¯ observed from the shifting of N=0 to N=10.

Policy Convergence under Decentralization: Lessons from Indonesia’s Response to the COVID-19 Pandemic

Research on policy convergence has developed very significantly in comparative literature. However, little is known about the dynamics of policy convergence under unitary systems, assuming that they have greater convergence than under federal systems. This research maintains that unitary systems present no less intricate dynamics of policy convergence than the federal systems. Looking at a decentralized unitary system, this research argues that the dynamics of policy divergence is primarily driven by a need to pursue responsiveness to local priorities. It assesses the case of Indonesia in responding to the COVID-19 pandemic through qualitative and quantitative exploration, combining documentary and the named entity recognition (NER) methods. The main data were sourced from the selected national newspapers sanctioned by the Indonesian Press Board. The result points to several factors affecting policy convergence, namely, responsiveness, compliance, policy inconsistency, policy clarity, leadership, horizontal learning, and electoral politics. Of these factors, the most important one is policy responsiveness; that is, whether national and subnational policies converge or diverge is affected by the need of a subnational government to respond to local priorities. This research fills the void in the current research by understanding the interplay between domestic factors and policy convergence, thereby extending the debate on the dynamic of policy convergence under a decentralized unitary system. Working with the COVID-19 pandemic adds nuances to the literature on crisis-driven policy convergence dynamics. It also points to a practical implication on the importance of crafting better institutional arrangements on national-subnational relations to better respond to pressing issues in a more convergent manner.

Optimizing mixed cool thermal storage systems across a connected community

A high level of electric demand flexibility must be integrated into our building infrastructure to enable greater renewable energy penetration in the grid. In the U.S., 9 % of electricity generated is used to cool buildings in a periodic manner, making this end-use an ideal target for active management through cool thermal energy storage (CTES) technologies. Historic uses for CTES are designed around central chilled water plants, but these systems cool less than 25 % of U.S. commercial floorspace. Emerging technologies are under development to serve the many smaller distributed cooling systems, such as rooftop units (RTUs), and have the potential to add CTES to an additional 66 % of cooled commercial floorspace. However, these unitary thermal storage systems (UTSS) lack the modeling and analysis tools to evaluate them in the future interactive grid context. This study develops the modeling and optimization tools necessary to simultaneously examine central and distributed ice storage systems within the multi-building, connected community context. An integrated simulation-optimization workflow is created to allow for rapid customized analysis. Results demonstrate the energy and flexibility tradeoffs of various implementations.

Information asymmetry and vertical collective action dilemma: The case of targeted poverty alleviation in China

AbstractInformation asymmetry is prevalent in the vertical bureaucratic structures of unitary systems. Drawing upon the institutional collective action (ICA) framework and the literature on information politics, this paper investigates the formation of the vertical ICA dilemma and the motivations underlying the collaborative mechanisms to address information asymmetry within the hierarchical bureaucratic structures of the Chinese government. Taking the Targeted Poverty Alleviation campaign as a case, we find a mixture of collective solutions, including informal networks, intergovernmental contracts, delegation, and imposed authority, as alternatives to alleviate the information asymmetry between vertical governments. Our case studies contribute to the literature on central–local relations, information politics, and the development of the vertical ICA framework, which notably incorporates the extent of lower level government autonomy into the determinants of integration mechanisms. In the conclusion, we connect this research to the broader ICA research agenda and studies of the cross‐level policy process, with implications for multi‐level governance in unitary systems like China.

Reduction Performance and Mechanism of Liquid Terminated-Carboxyl Fluoroelastomers Using Unitary or Binary Metal Hydride Reduction Systems

Reduction Performance and Mechanism of Liquid Terminated-Carboxyl Fluoroelastomers Using Unitary or Binary Metal Hydride Reduction Systems

Zig-zag-matrix algebras and solvable quasi-Hermitian quantum models

In quantum mechanics of unitary systems using non-Hermitian (or, more precisely, Θ-quasi-Hermitian) Hamiltonians H such that , the exactly solvable M-level bound-state models with arbitrary are rare. A new class of such models is proposed here, therefore. Its exact algebraic solvability (involving not only the closed formulae for wave functions but also the explicit description of all of the eligible metrics Θ) was achieved due to an extremely sparse (viz., just -parametric) but still nontrivial ‘zig-zag-matrix’ choice of the form of H.

Intensity-induced phase in linear optics.

We identify situations where optical phase modulation can be induced by intensity variations in the linear domain. In particular, for scalar two-beam in and two-beam out spatial unitary systems (beam splitters), we find that the phase difference between the output beams can be altered by changing the intensity ratio of the input beams. Utilizing this principle, we show that in linear optics (even in a very low-intensity regime), it is possible to introduce a two-dimensional spatial phase profile by spatial intensity modulation, thus affecting the propagation and far-field distribution of the ensuing beam.

Monotone Lagrangians in cotangent bundles of spheres

We study the compact monotone Fukaya category of T⁎Sn, for n≥2, and show that it is split-generated by two classes of objects: the zero-section Sn (equipped with suitable bounding cochains) and a 1-parameter family of monotone Lagrangian tori (S1×Sn−1)τ, with monotonicity constants τ>0 (equipped with rank 1 unitary local systems). As a consequence, any closed orientable spin monotone Lagrangian (possibly equipped with auxiliary data) with non-trivial Floer cohomology is non-displaceable from either Sn or one of the (S1×Sn−1)τ. In the case of T⁎S3, the monotone Lagrangians (S1×S2)τ can be replaced by a family of monotone tori Tτ3.

Policy‐making, policy‐taking, and policy‐shaping: Local government responses to the COVID‐19 pandemic

AbstractThe COVID‐19 pandemic has challenged nations states across the world. They have implemented lockdown and social distancing and with the development of vaccines have gone to great lengths to build herd immunity for their populations. As place managers, local government has played a variety of roles supporting central government edicts related to social distancing and supporting local businesses impacted by lockdowns. The research reported here comparing the role local government has played in Australia, Canada, Italy, and New Zealand shows that they have at different times and for different issues been policy takers from central government, policy shapers, and policy makers adapting national strategies. Local government plays an important complementary role with central governments in both unitary and federal systems of government. The paper contributes to the literature on multi‐level governance, place‐based decision‐making, and disaster and emergency management by offering a framework for analysing municipal roles in crises management both in their relationship with higher layers of government and in their acting as locally placed organisations.Points for practitioners Cross‐national study: Australia, Canada, Italy, and New Zealand. Examination of local government responses to COVID‐19 pandemic as policy makers, takers, or shapers. Comparison of federal and unitary states.

Treatment of Thoracoabdominal Aortic Aneurysmal Degeneration Following Aortic Dissections at a Single Surgical Center Using a Physician-Assembled Branched Endovascular Stent Graft

Aneurysmal degeneration of aortic dissection portends significant morbidity and mortality consequences in the subacute and chronic phases of aortic dissection. This paper describes the use of a multi-branched stent graft system for the treatment of thoracoabdominal aneurysmal degeneration of dissections with visceral segment involvement and reports upon the 30-day and one-year outcomes for the first 18 patients treated with this design configuration. The in-hospital, 30-day and one-year morbidity and mortality outcomes of 18 consecutive patients treated with the physician-assembled visceral manifold or unitary manifold stent graft systems between 2013 and 2022 were evaluated. A total of 18 patients were treated for aneurysmal changes after aortic dissection. A total of 71 visceral vessels were successfully stented. There were no acute procedural failures. There were no episodes of paraplegia, reinterventions for type I or III endoleaks, patency-related events or mortalities reported in the first 30 days following treatment. One-year, all-cause mortality demonstrated 2/11 (18.2%). Aneurysmal degeneration of aortic dissection poses significant risks to patients with medically managed aortic dissections and those under surveillance. When these aneurysms develop in the thoracoabdominal region, treatment becomes even more challenging given the problem of visceral vessel patency, as these vessels can originate off the true or false lumens. The physician-designed endovascular stent graft system reported upon here has been successfully deployed in 18 patients with no acute procedural failures and promising clinical results. This treatment modality may offer utility to vascular surgeons whose patients with thoracoabdominal aneurysmal degeneration following aortic dissection have historically had limited endovascular repair prospects.

Energy performance assessment of Sea Water Air Conditioning (SWAC) as a solution toward net zero carbon emissions: A case study in French Polynesia

Sea Water Air Conditioning (SWAC) technology uses deep ocean water to cool buildings. It is a non-intermittent renewable thermal energy used directly without any transformation. It may replace other air-conditioning systems powered by electrical energy (mechanical vapor compression thermodynamic cycle) or powered by other renewable energies (solar heating and cooling systems). Despite its theoretical appeal as a solution to help achieve net-zero carbon emissions, and the existence of successful deployments, SWAC technology remains scarce worldwide mainly due to its investment cost (CAPEX). One reason for this failure to scale might be the absence of experimental data detailing energy performance of SWAC systems in real-world, commercial settings. Here is presented the performance of an existing 2.4 MW SWAC system, operated by The Brando resort on the atoll of Tetiaroa in French Polynesia. Under a tropical climate, experimental results show that the Coefficient of Performance (COP) of the SWAC system can reach 20 to 150 depending on the secondary loop length, compared with conventional vapor compression systems that peak at around 5 for the most efficient. To put this in terms of carbon emissions avoided, conventional unitary split systems running in similar hotels on neighboring islands in French Polynesia (COP around 3.5) emit some 860 Tons/year compared to the estimated 225 Tons/year emitted (approximated with the emissions factor of French Polynesia in 2019) operating the Tetiaroa SWAC.

Entangled multiplets and spreading of quantum correlations in a continuously monitored tight-binding chain

We analyze the dynamics of entanglement in a paradigmatic noninteracting system subject to continuous monitoring of the local excitation densities. Recently, it was conjectured that the evolution of quantum correlations in such system is described by a semi-classical theory, based on entangled pairs of ballistically propagating quasiparticles and inspired by the hydrodynamic approach to unitary (integrable) quantum systems. Here, however, we show that this conjecture does not fully capture the complex behavior of quantum correlations emerging from the interplay between coherent dynamics and continuous monitoring. We unveil the existence of multipartite quantum correlations which are inconsistent with an entangled-pair structure and which, within a quasiparticle picture, would require the presence of larger multiplets. We also observe that quantum information is highly delocalized, as it is shared in a collective {\it nonredundant} way among adjacent regions of the many-body system. Our results shed new light onto the behavior of correlations in quantum stochastic dynamics and further show that these may be enhanced by a (weak) continuous monitoring process.