Abstract: Upper Tropsphere (UT) humidity records are crucial for climat studies.  Pseudo-monthly averaging is applied to maximize temporal representativeness, and enhance the lidar signal allowing to provide WVMR profiles up to 16 km. This study evaluates 11 years (2013–2023) of water vapor mixing ratio (WVMR) profiles from a UV Raman lidar (Lid1200) at the Reunion Island against MLS-Aura satellite retrieval, ERA5 reanalysis, and GRUAN-processed M10 radiosondes.  Results show a systematic dry bias in MLS of up to 30% above 12 km, particularly during the wet season. Lidar exhibits a small underestimates of WVMR around 5% drier than ERA5 all over the UT, with the largest deviations above 14 km, and larger variability during the wet season, Lidar calibration-related challenges during the dry season results in drier than ERA5 WVMR profiles (up to 10%). Aditionnaly, comparisons with GRUAN-processed radiosonde reveal a substantial lidar dry bias, exceeding 100% above 12 km.  Both lidar dry biases might be linked to the GNSS-based lidar calibration. Applying an alternative calibration method produces higher WVMR values, reducing the lidar dry bias w.r.t GRUAN by about 50% at upper-tropospheric levels, improving it's agreement with radiosondes, and revealing ERA5 dry bias increasing with altitude at the UT up to 25%. These efforts complement the global interest in the monitoring and validation of subtropical upper-tropospheric humidity.

Abstract: We propose a thermodynamic variational framework in which quantum mechanics, classical dynamics, and gravitation emerge as equilibrium regimes of a single free-energy functional defined on probability distributions rather than on trajectories, wavefunctions, or spacetime metrics. The functional balances Fisher information, potential energy, and Shannon entropy, encoding an exploration–exploitation trade-off uniquely fixed by information-theoretic considerations. Matching the Fisher term to the quantum kinetic energy fixes its coefficient without free parameters. Extremization of the functional yields the continuity equation and the quantum Hamilton–Jacobi equation, and thus reproduces the Schrödinger equation as a thermodynamic equilibrium condition. At mesoscopic scales, competition between Fisher information and entropy introduces a characteristic quantum–classical crossover length that provides a thermodynamic perspective on decoherence. Measurement is interpreted as an irreversible thermodynamic transition, with energetic costs bounded by Landauer's principle. In the macroscopic regime, we show that requiring thermodynamic stability and local boundary response selects area-law entropy scaling as the leading contribution under stated assumptions. Given an area-law entropy, standard local arguments recover Einstein's field equations. The framework yields falsifiable predictions across quantum, mesoscopic, and gravitational regimes.

Abstract: Area-law entropy appears in quantum many-body systems and gravitational physics, whereas classical thermodynamics treats entropy as volume-extensive. Rather than reflecting competing fundamental principles, we show that these scalings correspond to distinct thermodynamic stability regimes. Using a minimal information-theoretic free-energy functional combining Fisher information and Shannon entropy, we analyze entropy scaling under three physically unavoidable requirements: locality of response, existence of thermodynamic equilibrium, and universality of gravitational coupling. Within this framework, we prove that volume-law entropy cannot define an intrinsically stable equilibrium for isolated macroscopic systems and is therefore viable only as an externally stabilized, mesoscopic approximation. We identify three regimes. At microscopic scales, Fisher dominance and locality of information propagation enforce area-law entropy. At intermediate scales, volume-law entropy emerges as a metastable regime sustained by non-gravitational confinement. At macroscopic scales dominated by self-gravity, we show that thermodynamic stability and composition-independent equilibrium uniquely require area-law entropy; any more extensive scaling leads either to instability or to violations of the equivalence principle. Volume-law entropy is thus identified as a mesoscopic anomaly rather than a fundamental property of matter. Area-law scaling emerges as the only entropy behavior consistent with a unified thermodynamic description spanning quantum coherence and gravitational universality.

Abstract: Statistical entropy introduced in Boltzmann's combinatorial argument played a crucial role in the development of modern physics, yet it is limited to ideal monatomic gases. Statistical mechanics developed by Gibbs is suitable for any system, and this approach yielded important practical results. Unfortunately, the Gibbs statistical entropy remains constant during an irreversible process in the isolated system. This led to the conclusion that entropy is subjective — that entropy of a system is related to ignorance or information gained by an external observer during measurement. At present, arguments for the objectivity of entropy are related to the microcanonical Boltzmann entropy in the system phase space. The advantages and disadvantages of the Boltzmann entropy are discussed. Carnap's principle of physical magnitudes is also considered.

Abstract: The persistent H0 and growth tensions in ΛCDM cosmology motivate a re-examination of the expansion paradigm’s foundational assumptions. The Dead Universe Theory (DUT) proposes an alternative in which observable galaxy separation is not due to metric expansion but results from irreversible, entropy-driven deformation of a viscoelastic spacetime continuum undergoing global gravitational retraction. This work formalizes DUT within a relativistic continuum-mechanics framework. We derive the entropic deformation tensor Ξ_μν from a variational principle and incorporate it into the Einstein field equations as G_μν + Ξ_μν = 8πG T_μν, replacing the cosmological constant with a dynamical, entropy-sourced curvature. A key prediction follows from the asymptotic stability analysis of the resulting system: a unique, non-adjustable growth index γ = (√5 − 1)/2 ≈ 0.6180339887…, the signature of the theory’s Unique Vacuum Attractor. Consequently, a high-precision measurement of the growth index consistent with γ ≈ 0.55 at the <0.01 level would strongly falsify DUT. This formulation provides a falsifiable, thermodynamically grounded geometric description of cosmic dynamics, directly linking late-time acceleration-like phenomena to residual entropy gradients of a “dead” gravitational substrate. Numerical validation of the attractor is available in the mission-grade inference pipeline (repository and preprint DOI provided in the Data/Code Availability statement).

Abstract: The thermodynamic behavior of many complex physical systems is strongly influenced by the structure of their underlying energy landscapes, particularly by the presence of exponentially many metastable states. While such landscape-level properties are central to the physics of glasses and disordered systems, they are not explicitly represented in standard thermodynamic state spaces. In this work, we develop a constrained equilibrium thermodynamic framework in which configurational complexity, defined as the logarithmic density of metastable states, is treated as an explicit macroscopic coordinate. Starting from the principle of maximum entropy, we construct equilibrium ensembles subject to simultaneous constraints on energy and configurational complexity, leading to a generalized Gibbs distribution characterized by a conjugate complexity control parameter. Within this framework, extended thermodynamic relations arise naturally as constrained equilibrium identities, without modification of the fundamental laws of thermodynamics. The formalism is illustrated through a worked example based on a mean-field glassy landscape, where configurational complexity can be computed explicitly. In this setting, complexity bias alters the saddle-point structure of the partition function, produces nontrivial response functions, and yields clear signatures of structural transitions. An extension to thermodynamic geometry further demonstrates how reorganizations of the energy landscape manifest as geometric features in an enlarged thermodynamic state space. The results presented here provide a systematic and physically grounded approach to incorporating landscape-level complexity into equilibrium thermodynamics. Rather than proposing universal energetic bounds, the framework offers a model-dependent tool for analyzing how configurational structure influences thermodynamic behavior in complex systems.

Abstract: Numerical studies on the dynamics of bubble clusters in a compressible fluid, including interfacial heat and mass transfer, were performed to investigate the behaviour of bubble clusters in cavita-tion devices. The influence of operational and system parameters on the intensity of cavitation processes was considered. Physicochemical transformations during the cavitation treatment of liquids are caused not only by the action of shock waves and emitted pressure pulses but also by extreme thermal effects. At the stage of ultimate bubble compression, the vapour inside the bubble and the liquid in its vicinity transition to a supercritical fluid state. The presented model analyses the nature of microflows in the inter-bubble space and performs a quantitative calculation of the local values of velocity and pressure field parameters.

Abstract: A mathematical Kelvin formulation of the second law of thermodynamics in the form of a limit is proposed: If the efficiency of a heat engine approaches unity, then the rejected work vanishes. This limit allows deriving the behavior of a Carnot cycle near absolute zero of temperature. Also, the unattainability of absolute zero can be shown. In turn, these results allow deriving the behavior of the entropy near absolute zero, as has already been shown previously. The point of view is the phenomenological, macroscopic, and non-statistical one of classical thermodynamics.

Abstract: The cosmological constant problem—QFT vacuum energy exceeding observations by \( 10^{120} \)—remains unsolved without fine-tuning or anthropics. We present a semiclassical determination of \( \Omega_\Lambda \) from Standard Model field content on a spherical cosmological horizon. Under a small set of discrete modeling assumptions (M1–M4), we project Standard Model fields onto the monopole (\( \ell = 0 \)) block of a spherical horizon at radius \( R \sim H_0^{-1} \), apply Kubo-Martin-Schwinger (KMS) thermal weighting at the Gibbons-Hawking temperature \( T_{\mathrm{GH}} = \hbar c/(2\pi k_{\mathrm{B}} R) \), and use symmetry-fixed greybody factors. All boundary terms vanish by gauge/color/parity symmetries, with a geometric heat-kernel correction for bosons. The calculation yields a dimensionless loading \( \Delta^* = 17.46 \), which maps to \( \Omega_\Lambda = \Delta^*/(8\pi) = 0.695 \pm 0.008_{\mathrm{th}} \) via a geometric normalization fixed by the causal diamond solid angle. Comparison with DESI 2024 + CMB data \( \Omega_\Lambda^{\mathrm{obs}} = 0.693 \pm 0.005 \) shows agreement within \( 0.2\sigma \). Every coefficient derives from Standard Model structure, spherical geometry, or thermal physics—no uncanceled UV divergences or fitted continuous parameters under assumptions M1–M4.

Abstract: Using the concept of quantum wave probability, combined with the identity principle, we can derive the Boltzmann distribution, Fermi distribution, and Bose distribution. Different distributions correspond to different conditions. The Boltzmann condition corresponds to the Boltzmann distribution. The Fermi condition corresponds to the Fermi distribution. The Bose condition corresponds to the Bose distribution. This demonstrates that the foundation of these three statistical distributions is quantum wave probability, all originating from quantum mechanics. The Boltzmann distribution is also an independent quantum distribution and is not simply a sparse limit of the Fermi or Bose distributions. The essence of the Boltzmann distribution is a uniform distribution. The Fermi and Bose distributions are deviations from the uniform distribution. Boltzmann entropy based on the quantum wave probability can resolve the Gibbs paradox. Using this new approach, we can also derive the results of eigenstate thermalization. The equilibrium state is the state in which all eigenstates have the same temperatures. We need to rethink the fundamentals of statistical mechanics.

Abstract:

This paper advances Coherence Thermodynamics for understanding systems composed purely of information and coherence. It derives five laws of coherence thermodynamics and applies them to two case studies. Three canonical modes of coherent informational systems are developed: Standing State, Computation Crucible, and Holographic Projection. Each mode has its own dynamics and natural units, with thermodynamic coherence defined as the reciprocal of the entropy–temperature product. Within this theory, reasoning is proposed to emerge as an ordered, work‑performing process that locally resists entropy and generates coherent structure across universal features.

Abstract: We present a fully controlled thermodynamic study of the two-dimensional dipolar $Q$-state clock model on small square lattices with free boundaries, combining exhaustive state enumeration with noise-free evaluation of canonical observables. We resolve the complete energy spectra and degeneracies $\{E_n,c_n\}$ for the Ising case ($Q=2$) on lattices of size $L=3,4,5$, and for clock symmetries $Q=4,6,8$ on a $3\times3$ lattice, tracking how the competition between exchange and long-range dipolar interactions reorganizes the low-energy manifold as the ratio $\alpha = D/J$ is varied. Beyond a finite-size characterization, we identify several qualitatively new thermodynamic signatures induced solely by dipolar anisotropy. First, we demonstrate that ground-state level crossings generated by long-range interactions appear as exact zeros of the specific heat in the limit $C(T \rightarrow 0,\alpha)$, establishing an unambiguous correspondence between microscopic spectral rearrangements and macroscopic caloric response. Second, we show that the shape of the associated Schottky-like anomalies encodes detailed information about the degeneracy structure of the competing low-energy states: odd lattices ($L = 3,5$) display strongly asymmetric peaks due to unbalanced multiplicities, whereas the even lattice ($L = 4$) exhibits three critical values of $\alpha$ accompanied by nearly symmetric anomalies, reflecting paired degeneracies and revealing lattice parity as a key organizing principle. Third, we uncover a symmetry-driven crossover with increasing $Q$: while the $Q=2$ and $Q=4$ models retain sharp dipolar-induced critical points and pronounced low-temperature structure, for $Q \ge 6$ the energy landscape becomes sufficiently smooth to suppress ground-state crossings altogether, yielding purely thermal specific-heat maxima. Altogether, our results provide a unified, size- and symmetry-resolved picture of how long-range anisotropy, lattice parity, and discrete rotational symmetry shape the thermodynamics of mesoscopic magnetic systems. We show that dipolar interactions alone are sufficient to generate nontrivial critical-like caloric behavior in clusters as small as $3\times3$, establishing exact finite-size benchmarks directly relevant for van der Waals nanomagnets, artificial spin-ice arrays, and dipolar-coupled nanomagnetic structures.

Abstract: As remarked by Boltzmann, the Second Law of Thermodynamics is notable for the fact that it is readily proved using elementary statistical arguments, but becomes harder and harder to verify the more precise the microscopic description of a system. In this article, we investigate one particular realization of the 2nd Law, namely Joule heating in a wire under electrical bias. We analyze the production of entropy in an exactly solvable model of a quantum wire wherein the conserved flow of entropy under unitary quantum evolution is taken into account using an exact formula for the entropy current of a system of independent quantum particles. In this exact microscopic description of the quantum dynamics, the entropy production due to Joule heating does not arise automatically. Instead, we show that the expected entropy production is realized in the limit of a large number of local measurements by a series of floating thermoelectric probes along the length of the wire, which inject entropy into the system as a result of the information obtained via their continuous measurements of the system. The decoherence resulting from inelastic processes introduced by the local measurements is essential to the phenomenon of entropy production due to Joule heating, and would be expected to arise due to inelastic scattering in real systems of interacting particles.

Abstract: We develop an informational extension of spacetime thermodynamics in which local entropy production is coupled to spacetime curvature within an effective covariant framework. Spacetime is modeled as a continuum limit of finite-capacity information registers, giving rise to a coarse-grained entropy field whose gradients define an informational flux. Within a nonminimally coupled scalar–tensor formulation, the resulting field equations imply that the local divergence of this flux is sourced by the Ricci scalar, establishing a direct relation between curvature and entropy production. The corresponding integral form links cumulative entropy generation to the integrated spacetime curvature over a causal region. In stationary limits, the framework reproduces the Bekenstein–Hawking entropy of horizons, while in homogeneous expanding cosmologies it yields monotonic entropy growth consistent with the observed arrow of time. The construction remains compatible with unitarity at the microscopic level and with holographic entropy bounds in the stationary limit. Numerical solutions in flat FLRW backgrounds are used as consistency checks of the coupled evolution equations and confirm the expected curvature–entropy behavior across cosmological epochs. Overall, the results provide a thermodynamically consistent interpretation of curvature as a geometric source of irreversible information flow, without modifying the underlying gravitational field equations.

Abstract: Generative diffusion models have emerged as a powerful class of models in machine learning, yet a unified theoretical understanding of their operation is still developing. This paper provides an integrated perspective on generative diffusion by connecting the information-theoretic, dynamical, and thermodynamic aspects. We demonstrate that the rate of conditional entropy production during generation (i.e. the generative bandwidth) is directly governed by the expected divergence of the score function's vector field. This divergence, in turn, is linked to the branching of trajectories and generative bifurcations, which we characterize as symmetry-breaking phase transitions in the energy landscape. Beyond ensemble averages, we demonstrate that symmetry-breaking decisions are revealed by peaks in the variance of pathwise conditional entropy, capturing heterogeneity in how individual trajectories resolve uncertainty. Together, these results establish generative diffusion as a process of controlled, noise-induced symmetry breaking, in which the score function acts as a dynamic nonlinear filter that regulates both the rate and variability of information flow from noise to data.

Abstract: Self-organizing open systems, sustained by continuous fluxes between sources and sinks, convert stochastic motion into structured efficiency, yet a first-principles explanation of this transformation remains elusive. We derive the time-dependent Average Action Efficiency (AAE)—defined as events per total action—from a stochastic–dissipative least-action principle formulated within the Onsager–Machlup and Maximum Caliber path-ensemble frameworks. The resulting Lyapunov-type identity links the monotonic rise of AAE to the variance of action and to the rate of noise reduction, delineating growth, saturation, and decay regimes. Self-organization emerges from a reciprocal feedback between dynamics and structure: the stochastic dynamics concentrates trajectories around low-action paths, while the resulting structure, through the evolving feedback precision parameter β(t), modulates subsequent dynamics. This self-reinforcing coupling drives a monotonic increase of the dimensionless Average Action Efficiency α_t =η/⟨ I⟩_t , providing a quantitative measure of organizational growth. In the deterministic limit, the theory recovers Hamilton’s Principle. The increase of AAE corresponds to a decrease in path entropy, yielding an information-theoretic complement to the Maximum Entropy Production and Prigogine–Onsager variational formalisms. The framework applies to open, stochastic, feedback-driven systems that satisfy explicit regularity conditions. In Part II, agent-based ant-foraging simulations confirm sigmoidal AAE growth, plateau formation, and robustness under perturbations. Because empirical AAE requires only event counts and integrated action, it offers a lightweight metric and design rule for feedback-controlled self-organization across physical, chemical, biological, and active-matter systems.

Abstract: Entropy appears in physics in many forms—thermal, quantum, informational, gravitational—yet its conceptual foundations remain disparate. We propose a unified definition of entropy grounded in global physical constraints. A constraint set C determines the admissible microstate region Γ(C), and the entropy is defined as S(C) = k_BlnVol[Γ(C)]. This constraint–volume formulation applies uniformly to classical and quantum systems, to internal and external degrees of freedom, and to finite or continuous state spaces, without invoking coarse-graining, ensembles, or subjective information. Local interactions generically weaken global constraints such as coherence, correlations, gradients, and entanglement structure. We prove a structural Second Law: whenever constraints decay under dynamical evolution, C(t +∆t) ⊆ C(t), the entropy must increase. This mechanism explains thermodynamic irreversibility, decoherence, thermalization, and hydrodynamic mixing as manifestations of constraint erosion, while identifying integrable and symmetry-protected systems as the exceptional cases in which constraints persist. The framework clarifies how macroscopic entropy can grow evenwhenmicroscopic dynamics are reversible, and why time itself is not a form of entropy. Classical thermodynamic entropy, quantum von Neumann entropy, and black hole entropy all emerge as special cases of the same structural principle.

Abstract:

The historical context of Szilard’s thought experiment is considered: Maxwell’s demon, Brownian motion, and naturalization of Maxwell’s demon by Smoluchowski. After that, the discussions of Szilard’s thought experiment in the second half of the 20th century are described: the penetration of information into statistical mechanics, the works of Brillouin, Bennett (Landauer’s principle) and Zurek. The second part of the paper is devoted to the criticism of thermodynamics of information. The critique of Earman and Norton is extended by considering levels of organization. Also, the problem of coordination with respect to information is discussed.

Abstract: In this paper, during the simulation analysis of a Curie phase transition shielding model, it was found that the cumulative mechanical work performed on a moving ferromagnet after one Curie phase transition cycle of the model is non-zero. Further analysis based on Curie phase transition theory and the thermodynamics of magnetic media indicates that after completing one phase transition cycle, the cumulative magnetization work on the Curie phase transition ferromagnet is zero, the internal energy of both the Curie ferromagnet and the entire model is conserved, yet mechanical work remains separately, which contradicts the conservation of energy. This discovery suggests that there are exceptions to the conservation of energy, and it is not absolute.

Abstract: This paper separately analyzes the thermodynamic processes of adiabatic superconducting phase transition in superconductors and adiabatic Curie phase transition in ferromagnets in magnetic fields. Through analysis, it is concluded that for an object undergoing a phase transition cycle, when the accumulated magnetization work is zero, the overall internal energy of the adiabatic phase transition system is conserved. However, in the model, the accumulated mechanical work done on the permanent magnet is not zero, which leads to non-conservation of energy in the model, contradicting the law of conservation of energy. This indicates that the law of conservation of energy also has exceptions and is not absolute.