Previous Paper Research Articles

The algebra of supernatural matrices

The algebra of supernatural matrices is a key example in the theory of locally finite central simple algebras, which we developed in a previous paper [T. Bar-On, Sh. Gilat, E. Matzri and U. Vishne, Locally finite central simple algebras, Algebras Represent. Theory 26(2) (2023) 553–607]. This algebra has appeared under various names before, and deserves further study. Supernatural matrices are a minimal solution to the equation of unital algebras [Formula: see text], which we compare to several similar conditions involving cancellation of matrices. Viewing a natural representation of this algebra, we show that supernatural matrices generalize both McCrimmon’s deep matrices algebra and [Formula: see text]-petal Leavitt path algebra. We also study their simple representations.

Using Polar Faculae to Determine the Sun’s High-latitude Rotation Rate. II. Simulations and New Measurements

Abstract In a previous paper, I described a new way of determining the high-latitude solar rotation rate statistically from spacetime maps of polar faculae observed in the 6767 Å continuum by the Michelson Doppler Interferometer on the Solar and Heliospheric Observatory. Now, I have tested the technique by applying it to simulated images whose faculae have known speeds, and I have been able to recover those speeds with an accuracy better than 0.01 km s−1. Repeated measurements of the Sun’s polar faculae gave the same high-latitude profile as before, but with a slightly faster synodic rotation rate of 9 . 10 ° day - 1 and a rotation period of 39.6 days. Applying this spacetime tracking procedure to magnetic flux elements observed with the Helioseismic Magnetic Imager on the Solar Dynamics Observatory, I obtained a similar rotation profile with a speed of 9.55° day−1 and a synodic rotation period of 37.7 days. These rates are comparable to polar rotation rates, obtained by other techniques, but the new latitude profiles are noticeably flatter than the quartic fits to those prior measurements.

Quantum nature of gravity in a Bose-Einstein condensate

The effect of noise induced by gravitons on a Bose-Einstein condensate has been explored in Sen and Gangopadhyay [Probing the quantum nature of gravity using a Bose-Einstein condensate, ]. In the previous paper, we investigated the effects of graviton while detecting a gravitational wave using a Bose-Einstein condensate. In this work, we shall explicitly calculate the decoherence due to the noise of gravitons for maximally entangled momentum states of the Bose-Einstein condensate. This decoherence happens due to bremsstrahlung from the Bose-Einstein condensates due to the effect of the noise induced by gravitons. It is observed that the maximally entangled state becomes entangled with the graviton state and it decays over time as a result of this gravitational bremsstrahlung. This new entangled state is termed as a Bose-Einstein supercondensate. Using this property of the Bose-Einstein condensate in a quantum gravity background, we propose an experimental test via the use of atom lasers (generated from the condensate) which would, in principle, help to detect gravitons in future generations of very advanced ultracold temperature experiments. Published by the American Physical Society 2025

Study of electronegativity from a network perspective

Using the undirected network from our previous paper, we constructed 5 directed networks based on 5 electronegativity scales. The direction of the edges is determined by the differences in electronegativity. We found that indegree and outdegree can be viewed as inherent chemical properties of elements. Thus, we define a new index—comparative attractiveness (CA)—to study the relationship between this index and electronegativity. The results indicate that CA and electronegativityis are correlated and highly consistent, and can be regarded as an internal property of elements. This index can be used to predict potential binary compounds and assess the rationality of electronegativity, providing valuable insights into the study of electronegativity and a new perspective on chemical properties.

Spontaneous torque on an inhomogeneous chiral body out of thermal equilibrium

In a previous paper we showed that an inhomogeneous body in vacuum will experience a spontaneous force if it is not in thermal equilibrium with its environment. This is due to the asymmetric asymptotic radiation pattern such an object emits. We demonstrated this self-propulsive force by considering an expansion in powers of the electric susceptibility: A torque arises in first order, but only if the material constituting the body is nonreciprocal. No force arises in first order. A force does occur for bodies made of ordinary (reciprocal) materials in second order. Here we extend these considerations to the torque. As one would expect, a spontaneous torque will also appear on an inhomogeneous chiral object if it is out of thermal equilibrium with its environment. Once a chiral body starts to rotate, it will experience a small quantum frictional torque, but much more important, unless a mechanism is provided to maintain the nonequilibrium state, is thermalization: The body will rapidly reach thermal equilibrium with the vacuum, and the angular acceleration will essentially become zero. For a small, or even a large, inhomogeneous chiral body, a terminal angular velocity will result, which seems to be in the realm of observability. Published by the American Physical Society 2025

Novel Dominance Principle Based Approach to the Solution of Two-person General Sum Games with n by m Moves

In a previous paper, the application of the dominance principle was proposed to find the noncooperative solution of the two-person, two-strategy general sum game with mixed strategies; in the literature, two different approaches are found: a prudential and a Nash approach leading to two different mixed strategies. Also, if the expected payoffs are equal in the two cases, the two strategies are not interchangeable. By the application of the dominance principle to the four combinations of the two classical solutions, it was possible to choose the equilibrium point avoiding the ambiguity due to their non-interchangeability. Starting from that result, it is here below proposed the extension of the method to two-person general sum games with n by m moves. The algebraic two multi-linear forms of the expected payoffs of the two players are studied. From these expressions of the expected payoffs, the derivatives are obtained, and they are used to find the dominating probability distribution on the moves. A conjecture about the uniqueness of the solution is proposed in order to solve the problem of the existence and uniqueness of the non-cooperative solution of a two-person n by m game. The unique non-cooperative solution could be used as a starting point to find out the cooperative solution of the game too. Some games from the sound literature are discussed in order to show the effectiveness of the presented procedure.

Unbiased Finite Element Mesh Delaunay Constrained Triangulation Applied to 2D Images with High Morphological Complexity Using Mathematical Morphology Tools Part 2: Labeled Images

We propose a method for generating a constrained Delaunay triangulation CDT applied to labeled 2D images with high morphological complexity. In the previous paper, Part 1, we established an unbiased planar straight-line graph (PLSG) on image objects of any morphological complexity, using mathematical morphology tools. In the case of labeled images of this paper, the PSLG is defined by the set of local PSLG pieces for each adjacent label. The global PSLG of each label must respect the injective nature of Jordan’s curve.

Fast, Verified Computation for HOL ITPs

We add an efficient function for computation to the kernels of higher-order logic interactive theorem provers. First, we develop and prove sound our approach for Candle. Candle is a port of HOL Light which has been proved sound with respect to the inference rules of its higher-order logic; we extend its implementation and soundness proof. Second, we replicate our now-verified implementation for HOL4 with only minor changes, and build additional automation for ease of use. The automation exists outside of the HOL4 kernel, and requires no additional trust. We exercise our new computation function and associated automation on the evaluation of the CakeML compiler backend within HOL4’s logic, demonstrating an order of magnitude speedup. This is an extended version of our previous conference paper [2], which described implementation and soundness proofs for Candle. Our HOL4 implementation and automation are new, as are the CakeML benchmarks.

Hardy spaces and Riesz transforms on a Lie group of exponential growth

Abstract Let G be the Lie group ${\mathbb{R}}^2\rtimes {\mathbb{R}}^+$ endowed with the Riemannian symmetric space structure. Take a distinguished basis $X_0,\, X_1,\,X_2$ of left-invariant vector fields of the Lie algebra of G, and consider the Laplacian $\Delta=-\sum_{i=0}^2X_i^2$ and the first-order Riesz transforms $\mathcal R_i=X_i\Delta^{-1/2}$ , $i=0,1,2$ . We first show that the atomic Hardy space H1 in G introduced by the authors in a previous paper does not admit a characterization in terms of the Riesz transforms $\mathcal R_i$ . It is also proved that two of these Riesz transforms are bounded from H1 to H1.

Irreducible decomposition of powers of edge ideals, computing dstab, astab.

Find a primary irreducible decomposition of an ideal is a problem which goes back to Emmy Noether. Find the irreducible decomposition of the powers of an ideal is a more recent problem. In our previous paper we have described the irreducible decomposition of the powers of the edge ideal IG of a simple, connected non bipartite graph G. In this paper, we use some tools from graph theory, mainly Whitney’s theorem on ear decompositions of 2-edge connected graphs in order to introduce a new method to make a graph factor-critical. We can describe the set ∪ k = 1 ∞ Ass ( I G k ) in terms of some subsets of G. We give explicit formulas for the numbers astab ( I G ) and dstab ( I G ) which are the smallest number k such that Ass ( I G k ) = Ass ( I G k + i ) for all i ≥ 0 and the smallest number k such that the maximal ideal belongs to Ass ( I G k ) , respectively. We also give very simple upper bounds for astab ( I G ) and dstab ( I G ) .

Entropic Probability and Context States.

In a previous paper, we introduced an axiomatic system for information thermodynamics, deriving an entropy function that includes both thermodynamic and information components. From this function, we derived an entropic probability distribution for certain uniform collections of states. Here, we extend the concept of entropic probability to more general collections, augmenting the states by reservoir and context states. This leads to an abstract concept of free energy and establishes a relation between free energy, information erasure, and generalized work.

Beta-functions and RG flows for holographic QCD with heavy and light quarks: Isotropic case

In a previous paper [I. Y. Aref’eva , Running coupling for holographic QCD with heavy and light quarks: Isotropic case, ], we investigated the dependence of the running coupling constant on temperature and chemical potential for holographic models of the light and heavy quarks, supported by an Einstein-dilaton-Maxwell action. In this paper, we study the dependence of the corresponding β-functions on the temperature and the chemical potential. As in the previous paper, we give special attention to the behavior of the β-functions near the first order phase transitions. We consider different types of boundary conditions for the dilaton. Only one of the possible boundary conditions yields results that agree with lattice calculations at zero chemical potential. The corresponding β-functions are negative and exhibit jumps at the first order phase transitions. We also show that the renormalization group fluxes are invariant with respect to the choice of the boundary conditions and that our exact solutions for the light and heavy quarks are unstable, as expected, given their negative dilaton potentials. Published by the American Physical Society 2025

Vacuum transitions with the Gauss-Bonnet term in D dimensions

In our previous paper [; ], we proposed a probabilistic argument to explain the reason why the cosmological constant is very small in 4D. We can ask a question: if the behavior of tunneling exponent B can be generalized to D-dimension. Moreover, in higher dimensional theory motivated by string theory the Gauss-Bonnet term plays an important role. Therefore, in this paper, we generalize our result in previous paper [; ] to arbitrary D dimensions including the Gauss-Bonnet term. As a result, we have two main results. We find that the Euclidean action of the bounce, B, describing the decay of a de Sitter vacuum, is proportional to k+−(D−2), which has a pole as k+2→0 where k+2 is the curvature of the parent vacuum. This result is similar to the result in 4D. The other result is that we find a new decay channel, describing up-tunneling from anti–de Sitter into de Sitter. The meaning of this new decay channel in the string landscape should be explored in the future. Published by the American Physical Society 2025

Classification of 3-node restricted excitatory-inhibitory networks.

Classification of 3-node restricted excitatory-inhibitory networks.

Effect of a nonadiabatic magnetic field on the amplitude of cyclotron motion

This analysis extends the previously published study of the effect of a nonadiabatic magnetic field on the electron beam for different electron beam currents. Specifically, it presents 2-dimensional maps of relative amplitudes of radial beam oscillations in a space defined by nonadiabatic magnetic field strengths and electron beam currents. As before, the electron gun and the drift region are immersed in a uniform magnetic field to avoid distorting the cyclotron motion. Unlike in the previous paper, the cathode of the electron gun has a radius of 3 mm, which is more suitable for EBIS applications. These maps show the operating range of such an optical system with a nonadiabatic magnetic field and the options of optimizing the nonadiabatic coil strength and position for different electron beam currents.

Modulus estimates of semirings with applications to boundary extension problems

In our previous paper (Golberg et al. in Comput Methods Funct Theory 20(3–4):539–558, 2020), we proved that the complementary components of a ring domain in Rn with large enough modulus may be separated by an annular ring domain and applied this result to boundary correspondence problems under quasiconformal mappings. In the present paper, we continue this work and investigate boundary extension problems for a larger class of mappings.

The PLATO field selection process. II. Characterization of LOPS2, the first long-pointing field

PLAnetary Transits and Oscillations of stars (PLATO) is an ESA M-class mission to be launched by the end of 2026 to discover and characterize transiting planets around bright and nearby stars, and in particular habitable rocky planets hosted by solar-like stars. Over the mission lifetime, an average of 8% of the science data rate will be allocated to Guest Observer programs selected by ESA through public calls. Hence, it is essential for the community to know in advance where the observing fields will be located. In a previous paper, we identified two preliminary long-pointing fields (LOPN1 and LOPS1) for PLATO, respectively in the northern and southern hemispheres. Here we present LOPS2, a slightly adjusted version of the southern field that has recently been selected by the PLATO Science Working Team as the first field to be observed by PLATO for at least two continuous years, following the scientific requirements. In this paper, we describe the astrophysical content of LOPS2 in detail, including known planetary systems, bright stars, variables, binary stars, star clusters, and synergies with other current and future facilities.

Impact of varying usage profiles for different building envelope types with all-electric HVAC systems

In buildings, the usage profile has a significant impact on the operation of different building HVAC systems depending on building envelope designs. This study presents results of a larger study that looked at the influence of building envelope design and HVAC system configuration on the energy performance of a building with varying usage profiles. In a previous paper, the significant impact of thermal zoning methods was identified on the annual energy use in all-electric HVAC systems due to varying usage rates and climate. In this paper, the impact of usage variations considering building thermal mass (i.e., lightweight structure vs. heavyweight structure), window-to-wall ratio (10–40%), and HVAC system type (i.e., packaged single zone and variable air volume) in two different climates (i.e., hot-humid vs. cold-humid) are presented. The results of this study show that the energy use variations from varying usage profiles differed significantly depending on building thermal mass, window-to-wall ratio, and HVAC system type in two different climates (i.e., Houston, TX, and Chicago, IL). The results of this study will contribute to a better understanding of the hidden impacts of building envelope design and HVAC system type on annual energy use and peak load conditions.

Corrigendum of quadratic BSDEs with jumps and related PIDEs: Stochastics. 94 (3), 386–414, (2022)

In this short note we provide an additional term that was missing in the proof of Theorem 5.1 in section 5 (Comparison and strict comparison theorems) of our previous paper entitled: Quadratic BSDEs with jumps and related PIDEs.

Wavelength-Dependent Calcium Signaling Response to Photobiomodulation in Pancreatic Cells

Diabetes mellitus is a metabolic disorder that is rapidly growing across the world. Our laboratory has recently demonstrated that photobiomodulation (PBM) can couple to its metabolic pathways by modulating calcium dynamics in islet cells, including α- and β-cells. Using computer vision algorithms, changes in PBM-induced calcium dynamics can be verified, and, more importantly, this led us to propose hypotheses that will likely advance our understanding of photostimulatory effects in islet cells. In our previous paper, we determined changes in calcium spiking in response to PBM at 810 nm by manually segmenting the cells and the calcium spiking patterns. We have since developed a computer vison pipeline to automate cell segmentation and subsequent image analyses. By using automated methods for segmentation, registration, tracking, and statistical analysis, we were able to improve the accuracy of previously observed changes in calcium spiking in response to PBM in both cell types. Moreover, this pipeline was applied to elucidate the wavelength-dependent modulation of calcium dynamics at 1064 nm. The extent of increase in calcium spiking appears to have been overestimated by manual analysis, and the machine learning pipeline was able to capture and segment nearly 3-fold more cells, suggesting improved accuracy in the analysis of calcium spiking in islet cells. Detailed calcium analysis also indicates a biphasic dose response among α- and β-cells in response to PBM therapy at different wavelengths. The current findings offer a novel hypothesis and may facilitate the use of translational PBM as a potential therapy for diabetes mellitus.