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36 pages, 3212 KB  
Review
Bipolar Entropy vs. Entropy/Negentropy: From Quantum Emergence to Agentic AI&QI with Collectively Entangled Bipolar Strings ER ≥≥ EPR
by Wen-Ran Zhang and Hengyu Zhang
Quantum Rep. 2026, 8(2), 36; https://doi.org/10.3390/quantum8020036 - 20 Apr 2026
Viewed by 2230
Abstract
While the quantum emergence of spacetime is becoming a major research topic in physics, the quantum emergence of intelligence has not been widely researched in quantum information science (QIS). Following causal-logical quantum gravity theory, bipolar entropy vs. entropy and negative entropy (or negentropy) [...] Read more.
While the quantum emergence of spacetime is becoming a major research topic in physics, the quantum emergence of intelligence has not been widely researched in quantum information science (QIS). Following causal-logical quantum gravity theory, bipolar entropy vs. entropy and negative entropy (or negentropy) are reviewed and distinguished for quantum emergence/submergence of quantum agent (QA) and quantum intelligence (QI) in algebraic terms. This work refers to QA as an entangled bipolar string/superstring in bipolar dynamic equilibrium (BDE) and QI being centered on logically definable causality in regularity, mind-light-matter unity, and brain-universe similarity. ER = EPR is extended to ER ≥≥ EPR for the mathematical scalability of bipolar strings and their collective entanglement. The extension leads to a number of conjectures, testable predictions, and theorems. The term equilibraton is proposed as a type of EPR or bipolar generic string to serve as an entropic stitch to collectively hold the universe together as a quantum entanglement in BDE with ubiquitous, regulated local emergence and submergence of QA&QI. Equilibraton leads to the concept of bipolar entropy square—a complete entropic solution to the background issue in quantum gravity. With complete background independence, energy/information conservational bipolar entropy, energy/information invariance, bipolar entropy non-additivity, and equilibrium-based plateau concavity are introduced. The nature of the one-dimensional arrow of time is conjectured. As a unification of order and disorder for equilibrium-based regulation, bipolar entropy bridges QA&QI to agentic AI, where quantum-bio-economics can be viewed as a topological intervention of a natural dynamic equilibrium in a social or natural world. Use cases are reviewed to illustrate the practical and theoretical aspects of bipolar entropy in business management, quantum-bio-economics, quantum cryptography, physics, and biology. Eddington–Einstein’s comments on entropy are revisited. It is expected that bipolar entropy will bring quantum emergence/submergence to agentic AI&QI for entangled machine thinking and imagination as a naturally scalable and testable foundation of real-world quantum gravity, quantum information science (QIS), quantum cognition and quantum biology (QCQB) to enhance Large Language AI Models (LLMs) and machine intelligence. Full article
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19 pages, 3298 KB  
Article
An Enhancement in the Magnetocaloric Effect in a Composite Powder Based on Lanthanum Manganites
by Fidel Ivan Reyes Patricio, Cristhian Antonio Taboada Moreno, Ana María Bolarín Miró, Claudia Alicia Cortés Escobedo, María Isabel Reyes Valderrama and Félix Sánchez De Jesús
Materials 2025, 18(21), 4869; https://doi.org/10.3390/ma18214869 - 24 Oct 2025
Cited by 2 | Viewed by 761
Abstract
This study presents a dual-phase lanthanum manganite ceramic composite based on a mixture of equal weight ratios of La0.7Ca0.2Sr0.1MnO3 and La0.7Ca0.25Sr0.05MnO3 designed to enhance the magnetocaloric effect (MCE) of [...] Read more.
This study presents a dual-phase lanthanum manganite ceramic composite based on a mixture of equal weight ratios of La0.7Ca0.2Sr0.1MnO3 and La0.7Ca0.25Sr0.05MnO3 designed to enhance the magnetocaloric effect (MCE) of individual compounds, under a low magnetic field (≤18 kOe). X-ray diffraction (XRD) analysis revealed the coexistence of two orthorhombic manganite phases corresponding to the individual compounds, with no secondary phases detected. Temperature-dependent magnetization measurements in the composite evidenced two Curie temperatures at 286.8 K and 307.6 K, reflecting the effect of Ca2+ and Sr2+ concentrations. Arrott plots and β parameters confirmed that the phase transition is of second order. Although the maximum magnetic entropy change (ΔSM) of the composite is slightly lower than that of the individual manganite phases, its relative cooling power (RCP) reaches 188.82 J·kg−1, with an extended operational temperature window (OTW) of approximately 85 K, spanning from around 243 K to 328 K. This broad OTW enables efficient operation over a wider temperature range compared to similar materials, such as the individual La0.7Ca0.2Sr0.1MnO3 and La0.7Ca0.25Sr0.05MnO3 compounds, which exhibit an RCP of 55.24 and 65.12 J·kg−1, respectively, under a comparable magnetic field (~18 kOe). The improved magnetocaloric performance is attributed to interfacial exchange coupling and strain-mediated effects that broaden the ΔSM response and generate a non-additive RCP. These results demonstrate that interphase coupling and microstructural tuning effectively broaden the operating temperature range for magnetic refrigeration under moderate fields, making this composite a strong candidate for practical cooling applications. Full article
(This article belongs to the Special Issue Feature Papers in Materials Physics (2nd Edition))
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5 pages, 166 KB  
Editorial
Nonadditive Entropies and Nonextensive Statistical Mechanics
by Ugur Tirnakli
Entropy 2025, 27(1), 93; https://doi.org/10.3390/e27010093 - 20 Jan 2025
Viewed by 2160
Abstract
The centennial Boltzmann–Gibbs statistical mechanics [...] Full article
17 pages, 352 KB  
Article
Look Beyond Additivity and Extensivity of Entropy for Black Hole and Cosmological Horizons
by Mariusz P. Da̧browski
Entropy 2024, 26(10), 814; https://doi.org/10.3390/e26100814 - 25 Sep 2024
Cited by 7 | Viewed by 1913
Abstract
We present a comparative analysis of the plethora of nonextensive and/or nonadditive entropies which go beyond the standard Boltzmann–Gibbs formulation. After defining the basic notions of additivity, extensivity, and composability, we discuss the properties of these entropies and their mutual relations, if they [...] Read more.
We present a comparative analysis of the plethora of nonextensive and/or nonadditive entropies which go beyond the standard Boltzmann–Gibbs formulation. After defining the basic notions of additivity, extensivity, and composability, we discuss the properties of these entropies and their mutual relations, if they exist. The results are presented in two informative tables that are of strong interest to the gravity and cosmology community in the context of the recently intensively explored horizon entropies for black hole and cosmological models. Gravitational systems admit long-range interactions, which usually lead to a break of the standard additivity rule for thermodynamic systems composed of subsystems in Boltzmann–Gibbs thermodynamics. The features of additivity, extensivity, and composability are listed systematically. A brief discussion on the validity of the notion of equilibrium temperature for nonextensive systems is also presented. Full article
(This article belongs to the Special Issue The Black Hole Information Problem)
18 pages, 1647 KB  
Article
Spatial–Temporal Evolution and Driving Factors of Agricultural Green Development in China: Evidence from Panel Quantile Approaches
by Fanghui Pan, Haonan Deng, Miao Chen, Lijuan Zhao, Wei Qian and Xiangrong Wan
Sustainability 2024, 16(15), 6345; https://doi.org/10.3390/su16156345 - 24 Jul 2024
Cited by 5 | Viewed by 1976
Abstract
Agricultural green development has become essential for sustainable agriculture and the reduction of carbon dioxide emissions. This study evaluates the total index of agricultural green development by applying the entropy method; it then examines the spatial–temporal evolution of agricultural green development and finally [...] Read more.
Agricultural green development has become essential for sustainable agriculture and the reduction of carbon dioxide emissions. This study evaluates the total index of agricultural green development by applying the entropy method; it then examines the spatial–temporal evolution of agricultural green development and finally uses the panel quantile model to examine the driving factors of agricultural green development in China. The results indicate that the level of agricultural green development is rising with time, and the differences among the regions have not changed, showing an increasing direction from west to east. The results from the panel quantile regression with nonadditive fixed effects show that the driving factors have different impacts on agricultural green development across quantiles. Industrial structure upgrading, rural informatization, and agricultural marketization have more significant effects in provinces with higher agricultural green development; agricultural finance and the per capita GDP have greater impacts in provinces at a moderate level of agricultural green development; and technology development, rural informatization, and the urbanization rate play a more important role in provinces at a lower level of agricultural green development. Thus, each province should devise policies according to its level of agricultural green development, which would be beneficial in improving the policies’ effectiveness. Full article
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9 pages, 288 KB  
Article
Analogies and Relations between Non-Additive Entropy Formulas and Gintropy
by Tamás S. Biró, András Telcs and Antal Jakovác
Entropy 2024, 26(3), 185; https://doi.org/10.3390/e26030185 - 22 Feb 2024
Cited by 2 | Viewed by 1967
Abstract
We explore formal similarities and mathematical transformation formulas between general trace-form entropies and the Gini index, originally used in quantifying income and wealth inequalities. We utilize the notion of gintropy introduced in our earlier works as a certain property of the Lorenz curve [...] Read more.
We explore formal similarities and mathematical transformation formulas between general trace-form entropies and the Gini index, originally used in quantifying income and wealth inequalities. We utilize the notion of gintropy introduced in our earlier works as a certain property of the Lorenz curve drawn in the map of the tail-integrated cumulative population and wealth fractions. In particular, we rediscover Tsallis’ q-entropy formula related to the Pareto distribution. As a novel result, we express the traditional entropy in terms of gintropy and reconstruct further non-additive formulas. A dynamical model calculation of the evolution of Gini index is also presented. Full article
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22 pages, 16652 KB  
Review
Reminiscences of Half a Century of Life in the World of Theoretical Physics
by Constantino Tsallis
Entropy 2024, 26(2), 158; https://doi.org/10.3390/e26020158 - 11 Feb 2024
Cited by 2 | Viewed by 3292
Abstract
Selma Lagerlöf said that culture is what remains when one has forgotten everything we had learned. Without any warranty, through ongoing research tasks, that I will ever attain this high level of wisdom, I simply share here reminiscences that have played, during my [...] Read more.
Selma Lagerlöf said that culture is what remains when one has forgotten everything we had learned. Without any warranty, through ongoing research tasks, that I will ever attain this high level of wisdom, I simply share here reminiscences that have played, during my life, an important role in my incursions in science, mainly in theoretical physics. I end by presenting some perspectives for future developments. Full article
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21 pages, 501 KB  
Article
Constraints on Tsallis Cosmology from Big Bang Nucleosynthesis and the Relic Abundance of Cold Dark Matter Particles
by Petr Jizba and Gaetano Lambiase
Entropy 2023, 25(11), 1495; https://doi.org/10.3390/e25111495 - 29 Oct 2023
Cited by 28 | Viewed by 2846
Abstract
By employing Tsallis’ extensive but non-additive δ-entropy, we formulate the first two laws of thermodynamics for gravitating systems. By invoking Carathéodory’s principle, we pay particular attention to the integrating factor for the heat one-form. We show that the latter factorizes into the [...] Read more.
By employing Tsallis’ extensive but non-additive δ-entropy, we formulate the first two laws of thermodynamics for gravitating systems. By invoking Carathéodory’s principle, we pay particular attention to the integrating factor for the heat one-form. We show that the latter factorizes into the product of thermal and entropic parts, where the entropic part cannot be reduced to a constant, as is the case in conventional thermodynamics, due to the non-additive nature of Sδ. The ensuing two laws of thermodynamics imply a Tsallis cosmology, which is then applied to a radiation-dominated universe to address the Big Bang nucleosynthesis and the relic abundance of cold dark matter particles. It is demonstrated that the Tsallis cosmology with the scaling exponent δ∼1.499 (or equivalently, the anomalous dimension Δ∼0.0013) consistently describes both the abundance of cold dark matter particles and the formation of primordial light elements, such as deuterium 2H and helium 4He. Salient issues, including the zeroth law of thermodynamics for the δ-entropy and the lithium 7Li problem, are also briefly discussed. Full article
(This article belongs to the Special Issue The Statistical Foundations of Entropy II)
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16 pages, 5713 KB  
Article
Nonadditive Entropy Application to Detrended Force Sensor Data to Indicate Balance Disorder of Patients with Vestibular System Dysfunction
by Harun Yaşar Köse and Serhat İkizoğlu
Entropy 2023, 25(10), 1385; https://doi.org/10.3390/e25101385 - 27 Sep 2023
Cited by 2 | Viewed by 1783
Abstract
The healthy function of the vestibular system (VS) is of vital importance for individuals to carry out their daily activities independently and safely. This study carries out Tsallis entropy (TE)-based analysis on insole force sensor data in order to extract features to differentiate [...] Read more.
The healthy function of the vestibular system (VS) is of vital importance for individuals to carry out their daily activities independently and safely. This study carries out Tsallis entropy (TE)-based analysis on insole force sensor data in order to extract features to differentiate between healthy and VS-diseased individuals. Using a specifically developed algorithm, we detrend the acquired data to examine the fluctuation around the trend curve in order to consider the individual’s walking habit and thus increase the accuracy in diagnosis. It is observed that the TE value increases for diseased people as an indicator of the problem of maintaining balance. As one of the main contributions of this study, in contrast to studies in the literature that focus on gait dynamics requiring extensive walking time, we directly process the instantaneous pressure values, enabling a significant reduction in the data acquisition period. The extracted feature set is then inputted into fundamental classification algorithms, with support vector machine (SVM) demonstrating the highest performance, achieving an average accuracy of 95%. This study constitutes a significant step in a larger project aiming to identify the specific VS disease together with its stage. The performance achieved in this study provides a strong motivation to further explore this topic. Full article
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2 pages, 163 KB  
Editorial
Non-Additive Entropy Formulas: Motivation and Derivations
by Tamás Sándor Biró and Airton Deppman
Entropy 2023, 25(8), 1203; https://doi.org/10.3390/e25081203 - 13 Aug 2023
Cited by 1 | Viewed by 1702
Abstract
Entropy is a great tool in thermodynamics and statistical physics [...] Full article
(This article belongs to the Special Issue Non-additive Entropy Formulas: Motivation and Derivations)
16 pages, 366 KB  
Article
Non-Additive Entropic Forms and Evolution Equations for Continuous and Discrete Probabilities
by Evaldo M. F. Curado and Fernando D. Nobre
Entropy 2023, 25(8), 1132; https://doi.org/10.3390/e25081132 - 27 Jul 2023
Cited by 1 | Viewed by 1590
Abstract
Increasing interest has been shown in the subject of non-additive entropic forms during recent years, which has essentially been due to their potential applications in the area of complex systems. Based on the fact that a given entropic form should depend only on [...] Read more.
Increasing interest has been shown in the subject of non-additive entropic forms during recent years, which has essentially been due to their potential applications in the area of complex systems. Based on the fact that a given entropic form should depend only on a set of probabilities, its time evolution is directly related to the evolution of these probabilities. In the present work, we discuss some basic aspects related to non-additive entropies considering their time evolution in the cases of continuous and discrete probabilities, for which nonlinear forms of Fokker–Planck and master equations are considered, respectively. For continuous probabilities, we discuss an H-theorem, which is proven by connecting functionals that appear in a nonlinear Fokker–Planck equation with a general entropic form. This theorem ensures that the stationary-state solution of the Fokker–Planck equation coincides with the equilibrium solution that emerges from the extremization of the entropic form. At equilibrium, we show that a Carnot cycle holds for a general entropic form under standard thermodynamic requirements. In the case of discrete probabilities, we also prove an H-theorem considering the time evolution of probabilities described by a master equation. The stationary-state solution that comes from the master equation is shown to coincide with the equilibrium solution that emerges from the extremization of the entropic form. For this case, we also discuss how the third law of thermodynamics applies to equilibrium non-additive entropic forms in general. The physical consequences related to the fact that the equilibrium-state distributions, which are obtained from the corresponding evolution equations (for both continuous and discrete probabilities), coincide with those obtained from the extremization of the entropic form, the restrictions for the validity of a Carnot cycle, and an appropriate formulation of the third law of thermodynamics for general entropic forms are discussed. Full article
(This article belongs to the Special Issue Non-additive Entropy Formulas: Motivation and Derivations)
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17 pages, 1031 KB  
Article
Improving the Estimation of the Occurrence Time of an Impending Major Earthquake Using the Entropy Change of Seismicity in Natural Time Analysis
by Panayiotis A. Varotsos, Nicholas V. Sarlis, Efthimios S. Skordas, Toshiyasu Nagao, Masashi Kamogawa, E. Leticia Flores-Márquez, Alejandro Ramírez-Rojas and Jennifer Perez-Oregon
Geosciences 2023, 13(8), 222; https://doi.org/10.3390/geosciences13080222 - 25 Jul 2023
Cited by 15 | Viewed by 3146
Abstract
This article is focused on a new procedure concerning a more accurate identification of the occurrence time of an impending major earthquake (EQ). Specifically, we first recapitulate that, as was recently shown [P. Varotsos et al., Communications in Nonlinear Science and Numerical Simulation [...] Read more.
This article is focused on a new procedure concerning a more accurate identification of the occurrence time of an impending major earthquake (EQ). Specifically, we first recapitulate that, as was recently shown [P. Varotsos et al., Communications in Nonlinear Science and Numerical Simulation 125 (2023) 107370], natural time analysis of seismicity supplemented with the non-additive Tsallis entropy Sq leads to a shortening of the time window of an impending major EQ. This has been shown for the Tohoku mega-EQ of magnitude M9 that occurred in Japan on 11 March 2011, which is the largest event ever recorded in Japan. Here, we also show that such a shortening of the time window of an impending mainshock can be achieved for major, but smaller EQs, of the order of M8 and M7. In particular, the following EQs are treated: the Chiapas M8.2 EQ, which is Mexico’s largest EQ for more than a century that took place on 7 September 2017 near the coast of Chiapas state in Mexico, the 19 September 2017 M7.1 EQ that occurred within the Mexican flat slab, and the M7.1 Ridgecrest EQ on 6 July 2019 in California. Full article
(This article belongs to the Special Issue Precursory Phenomena Prior to Earthquakes 2023)
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9 pages, 457 KB  
Article
A Note on the Connection between Non-Additive Entropy and h-Derivative
by Jin-Wen Kang, Ke-Ming Shen and Ben-Wei Zhang
Entropy 2023, 25(6), 918; https://doi.org/10.3390/e25060918 - 9 Jun 2023
Cited by 1 | Viewed by 2127
Abstract
In order to study as a whole a wide part of entropy measures, we introduce a two-parameter non-extensive entropic form with respect to the h-derivative, which generalizes the conventional Newton–Leibniz calculus. This new entropy, Sh,h, is proved [...] Read more.
In order to study as a whole a wide part of entropy measures, we introduce a two-parameter non-extensive entropic form with respect to the h-derivative, which generalizes the conventional Newton–Leibniz calculus. This new entropy, Sh,h, is proved to describe the non-extensive systems and recover several types of well-known non-extensive entropic expressions, such as the Tsallis entropy, the Abe entropy, the Shafee entropy, the Kaniadakis entropy and even the classical Boltzmann–Gibbs one. As a generalized entropy, its corresponding properties are also analyzed. Full article
(This article belongs to the Special Issue Non-additive Entropy Formulas: Motivation and Derivations)
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21 pages, 3897 KB  
Article
Generalizing the Wells–Riley Infection Probability: A Superstatistical Scheme for Indoor Infection Risk Estimation
by Markos N. Xenakis
Entropy 2023, 25(6), 896; https://doi.org/10.3390/e25060896 - 2 Jun 2023
Cited by 1 | Viewed by 5110
Abstract
Recent evidence supports that air is the main transmission pathway of the recently identified SARS-CoV-2 coronavirus that causes COVID-19 disease. Estimating the infection risk associated with an indoor space remains an open problem due to insufficient data concerning COVID-19 outbreaks, as well as, [...] Read more.
Recent evidence supports that air is the main transmission pathway of the recently identified SARS-CoV-2 coronavirus that causes COVID-19 disease. Estimating the infection risk associated with an indoor space remains an open problem due to insufficient data concerning COVID-19 outbreaks, as well as, methodological challenges arising from cases where environmental (i.e., out-of-host) and immunological (i.e., within-host) heterogeneities cannot be neglected. This work addresses these issues by introducing a generalization of the elementary Wells-Riley infection probability model. To this end, we adopted a superstatistical approach where the exposure rate parameter is gamma-distributed across subvolumes of the indoor space. This enabled us to construct a susceptible (S)–exposed (E)–infected (I) dynamics model where the Tsallis entropic index q quantifies the degree of departure from a well-mixed (i.e., homogeneous) indoor-air-environment state. A cumulative-dose mechanism is employed to describe infection activation in relation to a host’s immunological profile. We corroborate that the six-foot rule cannot guarantee the biosafety of susceptible occupants, even for exposure times as short as 15 min. Overall, our work seeks to provide a minimal (in terms of the size of the parameter space) framework for more realistic indoor SEI dynamics explorations while highlighting their Tsallisian entropic origin and the crucial yet elusive role that the innate immune system can play in shaping them. This may be useful for scientists and decision makers interested in probing different indoor biosafety protocols more thoroughly and comprehensively, thus motivating the use of nonadditive entropies in the emerging field of indoor space epidemiology. Full article
(This article belongs to the Special Issue Non-additive Entropy Formulas: Motivation and Derivations)
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15 pages, 430 KB  
Article
Characteristic Function of the Tsallis q-Gaussian and Its Applications in Measurement and Metrology
by Viktor Witkovský
Metrology 2023, 3(2), 222-236; https://doi.org/10.3390/metrology3020012 - 18 May 2023
Cited by 6 | Viewed by 5645
Abstract
The Tsallis q-Gaussian distribution is a powerful generalization of the standard Gaussian distribution and is commonly used in various fields, including non-extensive statistical mechanics, financial markets and image processing. It belongs to the q-distribution family, which is characterized by a non-additive [...] Read more.
The Tsallis q-Gaussian distribution is a powerful generalization of the standard Gaussian distribution and is commonly used in various fields, including non-extensive statistical mechanics, financial markets and image processing. It belongs to the q-distribution family, which is characterized by a non-additive entropy. Due to their versatility and practicality, q-Gaussians are a natural choice for modeling input quantities in measurement models. This paper presents the characteristic function of a linear combination of independent q-Gaussian random variables and proposes a numerical method for its inversion. The proposed technique makes it possible to determine the exact probability distribution of the output quantity in linear measurement models, with the input quantities modeled as independent q-Gaussian random variables. It provides an alternative computational procedure to the Monte Carlo method for uncertainty analysis through the propagation of distributions. Full article
(This article belongs to the Collection Measurement Uncertainty)
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