Search Results (83)

This paper investigates how quantum entanglement and heterogeneous expectations jointly affect the stability, complexity, and controllability of a Cournot triopoly with isoelastic demand. Based on the Li–Du–Massar quantization scheme, we construct a discrete-time quantum Cournot triopoly in which three firms adopt different updating mechanisms: boundedly rational adjustment, naïve and adaptive expectations. The quantum boundary equilibrium and the unique interior quantum Nash equilibrium are derived explicitly. By linearizing the resulting three-dimensional nonlinear map and applying the Jury criterion, we obtain analytical local stability conditions for the interior equilibrium. The results show that increasing the entanglement level reduces the admissible range of the adjustment speed, thereby shrinking the stability domain and making the market dynamics more prone to bifurcation and chaos. Numerical simulations further reveal a typical transition from stable convergence to flip bifurcation, period-doubling cascades, chaotic attractors, and sensitive dependence on initial conditions. Finally, a control parameter is introduced to rescale the effective adjustment speed of the boundedly rational firm. This mechanism preserves the equilibrium set while restoring convergence to a stable fixed point once the control intensity exceeds a critical threshold. The findings highlight the joint role of entanglement, expectation heterogeneity, and nonlinear demand in shaping complex quantum oligopoly dynamics. Full article

In the 1930s and 1940s, Kumbum Monastery (Tibetan: sku’ bum byams pa gling) emerged as a significant spatial node in visual culture during the period of war and modern nation-building in the Republic of China (1912–1949). Through photography, painting, and film, a diverse range of visual media depicted the monastery’s architectural layout, inscribed plaques and steles, Cham dance (Tibetan: འཆམ་, Wylie: ’cham) rituals, lamaic prayers, and scenes of temple fairs and marketplaces. These visual representations not only documented historical detail but also constructed a composite space in which sacredness, transcendence, and secularity intersected. Due to its unique geographical location, religious doctrines, historical narratives, and political entanglements, Kumbum functioned as both a spiritual center and a politically charged symbol. Within this visual discourse, cham rituals and collective prayers were imbued with wartime ideological meanings, aligning religious transcendence with the national aspiration for resistance and victory. The inscribed plaques by state officials visually asserted political authority over sacred religious spaces, while the depiction of temple fairs foregrounded the entanglement of religious practices with everyday secular life, becoming key arenas for ethnic integration and political mobilization. Artists and photographers actively engaged with and reproduced both the symbolic and the quotidian landscapes of the monastery. These visual materials contributed to the broader project of narrating the Republic’s frontier and constructing the nation’s image. By examining how both monastic actors and external observers visually constructed Kumbum Monastery’s political and spiritual space, this study illuminates the complex interplay between religion and state power, and shows how visual media articulated ideological meanings and negotiated spatial relationships as collective responses to the site within the conditions of modernity. Full article

We develop a comparative synthesis of quantum-information geometry beyond complex numbers, with emphasis on what different algebraic frameworks contribute to information-processing structure rather than on their formal novelty alone. The organizing idea is a layer-by-layer test of the standard complex Hilbert-space formalism: each non-complex or deformed framework modifies the scalar field, phase group, projective state space, Born-probability semantics, composition rule, measurement geometry, symmetry algebra or representation category. The central thesis is that such frameworks are physically meaningful when they identify which assumptions make complex quantum mechanics operationally stable: positive probabilities, associative multipartite composition, reversible dynamics, experimentally testable phases, locality constraints, informationally complete measurements, error bases and clear operational semantics. Real quantum theory probes the necessity of complex phases and local tomography; quaternionic quantum mechanics probes non-Abelian phase while retaining associativity and admitting complex embeddings; octonionic proposals probe the boundary where exceptional geometry survives but generic circuit composition is obstructed by non-associativity; Jordan algebras test ordered probabilistic state spaces; Clifford algebras and Bott periodicity provide the spinorial and topological grammar connecting gates, Hopf maps and periodic dimensions; and quantum-group or q-deformed constructions probe coproducts, braiding and representation categories rather than scalar amplitudes. We distinguish three roles that are often conflated: genuine hypercomplex kinematics, Hopf-fibration coordinates for ordinary complex multipartite entanglement, and deformed algebraic or categorical structures. The resulting map separates established equivalence and experimental-constraint results from useful representation tools and speculative programs, while identifying concrete open problems for non-complex quantum information. Full article

We propose a structural framework for interpreting quantum computational advantage in terms of admissible continuation of configurations. In this framework, a quantum computation is described not only as a sequence of gates acting on a state vector but also as the organization of admissible histories whose phase contributions combine coherently in a manner related to sum-over-histories and path-integral formulations of quantum mechanics. We identify three structural features that are relevant to quantum advantage: the multiplicity of admissible histories, the degree of phase coherence among them, and the non-factorizable structure of continuation constraints corresponding to entanglement-like global dependence. To make these features explicit, we introduce the notion of effective coherent multiplicity, which measures the coherently usable portion of an admissible-history space before probability normalization. We then formulate a structural speedup conjecture: substantial quantum advantage requires not merely a large number of possible histories but scalable coherent multiplicity supported by non-factorizable constraints whose instability remains bounded. We also introduce a coherent-fiber criterion, which identifies phase-alignable families of histories selected by compact computational relations as a structural source of coherent amplification. This formulation does not replace standard complexity-theoretic measures such as circuit size, query complexity, or BQP membership. Rather, it provides a complementary structural language for relating those measures to interference, entanglement, decoherence, and the organization of computational history space. The framework clarifies, at a structural level, why raw branching alone is insufficient for speedup, why unstructured search yields only a limited advantage, and why problems with compact global regularities, such as Simon’s problem and period finding, can support stronger coherent amplification. The paper also discusses how the proposed quantities relate to standard notions, including success amplitudes, entanglement measures, tensor-network simulability, and fault-tolerance constraints. In this way, admissible-history structure is presented as a diagnostic viewpoint for understanding both the power and limitations of quantum computation. Full article

To explore the strong coupling between surface phonon polaritons (SPhPs) and quantum dots in one-dimensional periodic microstructures for quantum information processing, we establish a comprehensive theoretical model for SPhPs at air–polar dielectric interfaces. By rigorously deriving the dispersion relations, we reveal the decisive role of scale effects on bandgap formation: continuous spectra without bandgaps emerge at the nanoscale ($d\sim 10$–100 nm), whereas periodic modulation induces significant Bloch mode folding and tunable bandgaps (0.5–5 $\mathsf{\mu }\mathrm{m}$ width) at the microscale ($d\sim 1$–10 $\mathsf{\mu }\mathrm{m}$). Based on Fourier bandwidth limitations, we determine optimal channel widths ($L_y\ge 10 \mathsf{\mu }\mathrm{m}$) for maintaining low-loss modes with energy deviations below 1%. Through electromagnetic field quantization, we obtain analytical expressions for SPhP mode amplitudes and quantum dot transition rates. Calculations demonstrate that in micrometer-scale CsI structures, spontaneous emission rates can be modulated significantly: suppressed to <0.1 times the free-space values within bandgaps (excited-state lifetimes extended to ∼10 ns) and enhanced 5–8 times at conduction band edges. Leveraging these characteristics, we propose a scheme for batch quantum state manipulation of ${10}^2$–${10}^3$ arrayed quantum dots via selective excitation of specific Bloch modes using controlled laser frequency and angle, enabling parallel single-qubit gates with theoretical fidelity > 99%. Compared with surface plasmon polariton schemes, our approach utilizes the low-loss infrared characteristics of SPhPs ($Q\sim 100$–1000, 1–2 orders higher) to reduce decoherence rates, offering a new pathway for room-temperature solid-state quantum computing and on-chip multi-node entanglement distribution. Full article

The paper deals with the asymptotic behavior of a widely used correlation characteristic in large quantum systems. The correlation is quantum entanglement, the characteristic is entanglement entropy, and the system is an ideal gas of lattice fermions. If the one-body Hamiltonian of fermions is an ergodic finite difference operator with an exponentially decaying spectral projection, then the large-block form of the entanglement entropy is the so-called area law. However, the only class of one-body Hamiltonians for which this spectral condition was verified consists of discrete Schrödinger operators with random potential. In this paper, we prove the area law for several classes of Schrödinger operators whose potentials are ergodic but not random. We begin with quasiperiodic and limit-periodic operators and then move to a highly non-trivial case of potentials generated by subshifts of finite type. These arose in the theory of dynamical systems when studying chaotic phenomena. The corresponding asymptotic study requires involved spectral analysis, which therefore constitutes the bulk of the paper. Specifically, we prove uniform localisation of the eigenfunctions for the Maryland model and exponential decay of the eigenfunction correlator for various models. We believe these properties are of significant independent interest. Full article

This study introduces a novel Quantum-Inspired Hybrid Bald Eagle-Ukari Algorithm with Reinforcement Learning (QI-HBEUA-RL) for comprehensive optimization of conical solar distillers equipped with sand-filled copper conical fins. The proposed algorithm synergistically combines quantum computing principles (superposition and entanglement), bio-inspired metaheuristics (Bald Eagle Search and Ukari Algorithm), and reinforcement learning mechanisms to achieve unprecedented optimization performance in complex thermal-hydraulic systems. The QI-HBEUA-RL framework employs quantum-encoded population representation, enabling simultaneous exploration of multiple solution states, while reinforcement learning dynamically adjusts algorithmic parameters based on search landscape characteristics and historical performance data. Experimental validation tested seven distiller configurations in El-Oued, Algeria, under controlled conditions (7.85 kWh/m²/day solar radiation, 42.2 °C ambient temperature). The optimal configuration of copper conical fins with 14 g sand at 0 cm spacing achieved: daily productivity of 7.75 L/m²/day (+61.46% improvement over conventional design), thermal efficiency of 61.9%, exergy efficiency of 4.02%, and economic payback period of 5.8 days. Comprehensive algorithm comparison against six state-of-the-art multi-objective optimizers (NSGA-II, MOEA/D, MOPSO, MOGWO, MOHHO) across 30 independent runs demonstrated statistically significant superiority (p < 0.001, Wilcoxon test). QI-HBEUA-RL achieved 7.42% improvement in hypervolume indicator, 29.35% reduction in inverted generational distance, and 19.49% better solution spacing. Generalization validation on seven benchmark problems (ZDT1-6, DTLZ2, DTLZ7) and three renewable energy applications confirmed algorithm robustness across diverse problem types. Three real-world case studies, remote village water supply (238:1 benefit–cost), industrial facility (100% energy reduction), and emergency relief (740× cost savings) validate practical implementation viability. This research advances solar thermal desalination technology and multi-objective optimization methodologies, providing validated solutions for sustainable freshwater production in water-scarce regions. Full article

Doubly periodic tangles, or DP tangles, are embeddings of curves in the thickened plane that are periodically repeated in two directions. They are defined as universal covers of their generating cells, the flat motifs, which represent knots and links in the thickened torus, and which can be chosen in infinitely many ways. DP tangles are used in modeling materials and physical systems of entangled filaments. In this paper, we establish the complete mathematical framework of the topological theory of DP tangles. We present an exhaustive analysis of DP tangle isotopies. These are distinguished in local isotopies and global isotopies. Our analysis yields the characterization of DP isotopy as an equivalence relation on the level of their (flat) motifs, called DP tangle equivalence. Along the way, we also discuss motif minimality. We further generalize our results to other diagrammatic categories, namely framed, virtual, welded, singular, pseudo, tied and bonded DP tangles, which could be used in novel applications. Full article

Greater Ethiopia in the late medieval period, a somewhat delicate federation in the Horn constituted by the Christian highland kingdom and bordering Muslim princedoms, was integrated by interregional links of great significance, in a balance of roles within a wide trade network. Yet the interlacing web of connections saw as many disconnections. Sources from the Christian side as well as the Muslim side with its associated parties continue to provide light on various regional dynamics involved and allow analysis of how interactions were influenced by external actors such as Mamluk Egypt, the Ottoman Empire, and Christian Mediterranean states drawn by the belief that Abyssinia was ruled by Prester John. The purpose of this study is to expound the factors that shaped dealings between the two religio-political parties in order to help build a comprehensive perspective of the entangled milieu. The authors argue that a variety of conditions prevented domination by a single group and forged acceptance of a practical reality as a modus operandi. While several sources and references in Western languages on the wide regional interactions are known, this study aims to present a transcultural view on the topic through untapped Arabic studies examining related primary Arabic sources. Recent archeological work is also taken into account. Some emphases and clarifications are offered to promote an understanding of the region’s circumstances, the timing and aims of key episodes, and foreign interventions. Full article

Entangled-photon sources are indispensable components in free-space quantum key distribution (QKD) systems. Here, we present a compact, lightweight, and robust airborne entangled-photon source (AEPS) based on a Sagnac loop structure with single-mode fiber coupling. To meet the drone requirements for miniaturization, lightweight design, and high robustness, we developed a highly integrated entangled-photon source using customized miniature optical components and an adhesive bonding technique. The total volume and weight are only 38 × 40 × 24 mm³ and 58 g, respectively. Entangled-photon pairs at 810 nm are generated via Type-II spontaneous parametric down-conversion (SPDC) in a periodically poled KTiOPO₄ (PPKTP) crystal. We achieve a quantum state fidelity of F = 0.986 ± 0.0017, a photon-pair generation rate of 3.03 × 10⁶ pairs/s/mW, and a CHSH Bell parameter of S = 2.764 ± 0.082. Owing to its excellent size, weight, performance, and stability, the proposed entangled-photon source is particularly well suited for drone-based free-space mobile quantum communication. Full article

Filamentous opportunistic algae, which behave as opportunistic species, are frequently observed in Eriocheir sinensis aquaculture ponds. These algae can entangle Eriocheir sinensis and release harmful substances during decomposition, thereby negatively impacting farming performance. At present, their management largely depends on non-selective herbicides, while fundamental research on species composition and biomass dynamics remains limited. In this study, 19 aquaculture ponds across five E. sinensis farms in Shanghai were monitored over a two-year period. Filamentous algae species were identified using both morphological and molecular techniques, and their biomass and coverage were quantified. Concurrently, physicochemical parameters of the water were measured to analyze algal occurrence patterns and key environmental drivers. A total of 19 species belonging to four genera of the phyla Chlorophyta and Charophyta were identified. Rhizoclonium was the most common genus, followed by Cladophora and Spirogyra. These genera exhibited distinct seasonal succession, with Cladophora and Spirogyra dominating in spring, while Rhizoclonium predominanted in summer and autumn. Filamentous algal biomass reached its peak in May 2024, with a dry weight of 42.92 g/m². The two-way ANOVA results indicated significant main effects of month and region, as well as a significant month × region interaction. The Spearman correlation analysis revealed a strong positive association between algal biomass and pH. This pattern is consistent with the effect where the intense algal photosynthesis raises water pH through the uptake of dissolved carbon dioxide. The total biomass was significantly correlated with the nitrogen-to-phosphorus ratio, suggesting that nitrogen and phosphorus availability influenced algal growth. Moreover, filamentous algal coverage was positively associated with maximum algal biomass. The linear regression analysis further revealed that multiple environmental factors jointly contributed to algal proliferation, with total nitrogen, nitrate nitrogen, and fluorescent dissolved organic matter (fDOM) showing relatively strong associations with maximum biomass. These findings provide a scientific basis for the ecological control and targeted management of filamentous algae in aquaculture systems. Full article

We analysed data collected at the Innsbruck Alpenzoo (Tyrol, Austria) over 33 years (1988–2020). We examined data from 4542 wild birds of 137 species that were rescued in the increasingly urbanised and densely populated Inn Valley around Innsbruck and examined the outcome of hospital treatment (survival or death); for a subgroup of 3440 birds, we examined the length of stay at the zoo. The birds were divided into nine different groups, and the reasons for admission were divided into nine categories to analyse how the reasons for admission and membership of a bird group influences rehabilitation success and the duration of care required. Orphaned birds, birds that had become entangled in man-made structures, and birds with unknown reasons for admission had the best survival rates (60%), while birds with physical injuries, victims of collisions, and attacks by cats had the lowest survival rates (37%). Survival rates were highest among areal insectivores (66%) and waterbirds (62%), and lowest among small songbirds (45%) and woodpeckers (<39%), which suffered disproportionately from the consequences of window collisions. The overall survival rate of hospitalised birds (51%) was higher, and the duration of care required (median 11 days) was especially shorter at Innsbruck Alpenzoo than at most other rehabilitation centres. We attribute this mainly to the professional care and varied, group-specific diet provided to the patients, which we describe in detail. We also discuss the problems and limitations of wild bird care for zoo staff in addition to their daily tasks. Thereby, it became apparent that the retirement of experienced bird carers at the beginning of the study period and the subsequent steady changeover of staff members had a negative impact on success rates. Full article

Entangled photons are essential for photonic quantum technologies. Their generation typically relies on spontaneous parametric down-conversion, but conventional nonlinear crystals are bulky and hard to integrate on chips. Rhombohedral-stacked MoS₂ combines a high refractive index, large second-order nonlinearity, and flexibility for heterogeneous integration, making it a promising platform for integrated quantum photonics. However, the typical thin-film form of 3R-MoS₂ restricts the effective nonlinear interaction length, limiting entanglement generation efficiency in practical devices. To overcome this, phase-matching strategies in integrated waveguides are required but have so far remained undeveloped. Here, we introduce a waveguide-integrated 3R-MoS₂ platform with periodic grooves to achieve quasi-phase matching, enhancing down-conversion efficiency. Leveraging ${\chi }^{\left(2\right)}$ tensor symmetries and orthogonal waveguide modes, the design efficiently generates entangled photons, providing a compact, scalable route toward 2D-material-based integrated quantum photonic circuits. Full article

This paper innovatively achieves finite-time modified function projection synchronization (MFPS) for different fractional-order chaotic systems. By leveraging the advantages of radial basis function (RBF) neural networks in nonlinear approximation, this paper proposes a novel fractional-order sliding-mode controller. It is designed to address the issues of system model uncertainty and external disturbances. Based on Lyapunov stability theory, it has been demonstrated that the error trajectory can converge to the equilibrium point along the sliding surface within a finite time. Subsequently, the finite-time MFPS of the fractional-order hyperchaotic Chen system and fractional-order chaotic entanglement system are realized under conditions of periodic and noise disturbances, respectively. The effects of the neural network parameters on the performance of the MFPS are then analyzed in depth. Finally, a color image encryption scheme is presented integrating the above MFPS method and exclusive-or operation, and its effectiveness and security are illustrated through numerical simulation and statistical analysis. In the future, we will further explore the application of fractional-order chaotic system MFPS in other fields, providing new theoretical support for interdisciplinary research. Full article

Microplastics (MPs) are ubiquitous and persistent contaminants of the marine environment, but a clear understanding of their cycling, fate, and impacts in coastal zones is lacking. In this study, large MPs (1–5 mm) were sampled spatially and temporally from the strandline of a macrotidal, sandy beach (Polzeath) in southwest England. MPs encompassing a diversity of sources were categorised by morphology (foams, nurdles, biobeads, fragments, fibres, films) and quantified by number and mass, with a selection analysed for polymer type. A total of about 17,600 particles of around 350 g in mass were retrieved from 30 samples over a period of five months, with an abundance ranging from 35 and 2048 per m². The space- and time-integrated average mass of MPs on the beach strandline was about 2 kg and was dominated (>90%) by fragments, nurdles, and biobeads of polyethylene or polypropylene construction. Nurdles, biobeads, fragments, and, to a lesser extent, fibres were correlated with strandline seaweed abundance, which itself was correlated with previous storm activity. Relationships with seaweed abundance were also supported by visible associations of these MP morphologies with macroalgal deposits through entanglement and adhesion. These observations, coupled with a lack of MPs below the sand’s surface (50 cm depth), suggest that the majority of MPs are transported from an offshore stock with floating organic debris, resulting in a transitory strandline repository and a habitat enriched with small plastics. Full article