arXiv subjects

Arvind Kumar

Publications and source records attributed to Arvind Kumar.

At least 73 records · Page 4Linked to original sources

arXiv2024

Kaons and antikaons in isospin asymmetric dense resonance matter at finite temperature

We study the in-medium properties of kaons and antikaons in isospin asymmetric hot and dense resonance matter within the chiral SU(3) hadronic mean field model. Along with nucleons and hyperons, the interactions of $K$ and $\bar K$ mesons with all decuplet baryons ($Δ^{++,+,0,-}, Σ^{*\pm,0},Ξ^{*0,-}, Ω^{-}$) are explicitly considered in the dispersion relations. The properties of mesons in the chiral SU(3) model are modified at finite density and temperature of asymmetric resonance matter through the exchange of scalar fields $σ, ζ$ and $δ$ and the vector fields $ω, ρ$ and $ϕ$. The presence of resonance baryons in the medium at finite temperature is observed to modify significantly the effective masses of $K$ and $\bar{K}$ mesons. We also calculated the optical potentials of kaons and antikaons as a function of momentum in resonance matter. The present study of in-medium masses and optical potentials of kaons and antikaons will be important for understanding the experimental observables from the heavy-ion collision experiments where hot and dense matter may be produced. Our results indicate that when resonance baryons are present within the medium at finite baryonic density, the mass reduction of kaons and antikaons becomes more pronounced as the temperature of the medium increases from zero to 100 and 150 MeV. The study of the optical potentials of kaons and antikaons reveals a stronger correlation with strangeness fraction compared to isospin asymmetry.

hep-ph↗

arXiv2024

Effective masses and magnetic moments of charmed baryons in asymmetric hot strange hadronic matter

In the present work, we have studied the masses and magnetic moments of spin$-{\frac{1}{2}}^+$ and spin$-{\frac{3}{2}}^+$ singly and doubly charmed baryons in the strange hadronic medium at finite temperature using the chiral SU(3) quark mean field model. The properties of baryons within the framework of chiral SU(3) mean field model are defined in terms of constituent quark masses and energies, which are modified through the exchange of scalar fields $σ$, $ζ$ and $δ$ and the vector fields $ω$, $ρ$ and $ϕ$. The scalar-isovector field, $δ$ and the vector-isovector field, $ρ$ contribute when medium has finite isospin asymmetry. We have calculated the effective masses of constituent quarks and charmed baryons in the nuclear and strange matter within the chiral SU(3) quark mean field model and have used these as the input in SU(4) constituent chiral quark model to compute the effective magnetic moments of these baryons. Considering the configuration mixing, the contributions of valence quarks, quark sea and orbital angular momentum of quark sea have been considered explicitly to calculate the in-medium magnetic moments.

hep-ph↗

arXiv2024

Meijer-G Function with Continued Product and Integer Exponent: Performance of Multi-Aperture UOWC System over EGG Turbulence

Signal transmission over underwater optical wireless communication (UOWC) experiences the combined effect of oceanic turbulence and pointing errors statistically modeled using the sum of two Meijer-G functions. There is a research gap in the exact statistical analysis of multi-aperture UOWC systems that use selection combining diversity techniques to enhance performance compared to single-aperture systems. In this paper, we develop a general framework for the continued product and positive integer exponent for the sum of Meijer-G functions to analyze the exact statistical performance of the UOWC system in terms of multivariate Fox-H function for both independent and non-identically distributed (i.ni.d.) and independent and identically distributed (i.i.d.) channels. We also approximate the performance of a multi-aperture UOWC system with i.i.d. channels using the single-variate Fox-H function. Using the generalized approach, we present analytical expressions for average bit-error rate (BER) and ergodic capacity for the considered system operating over exponential generalized gamma (EGG) oceanic turbulence combined with zero-boresight pointing errors. We also develop asymptotic expressions for the average BER at a high signal-to-noise (SNR) to capture insights into the system's performance. Our simulation findings confirm the accuracy of our derived expressions and illustrate the impact of turbulence parameters for i.ni.d. and i.i.d. models for the average BER and ergodic capacity, which may provide a better estimate for the efficient deployment of UOWC.

eess.SP↗

arXiv2024

Does nuclear medium affect the transverse momentum-dependent parton distributions of valence quark of pions?

We calculate the valence quark transverse momentum-dependent parton distributions (TMDs) of the lightest pseudoscalar meson, pions, in isospin asymmetric nuclear matter at zero temperature by employing a light-cone quark model. The medium modifications in the pion unpolarized TMDs are induced through the effective quark masses computed using the chiral SU($3$) quark mean field model. The spin densities at different momentum fraction ($x$) have also been calculated at different baryonic densities.

hep-ph↗

arXiv2024

Pions valence quark distributions in asymmetric nuclear matter at finite temperature

We have calculated the valence quark distributions of the lightest pseudoscalar meson, pions, in the isospin asymmetric nuclear matter at zero and finite temperature employing a light-cone quark model. The medium modifications in the pion properties have been stimulated through the effective quark masses computed using the chiral SU($3$) quark mean field model. We have primarily focused on the impact of isospin asymmetric medium on the distribution amplitudes (DAs) and parton distribution functions (PDFs) of a valence quark for different baryon density and temperature values. Also, the DAs and PDFs have been evolved to $Q^2=10$ GeV$^2$ and $Q^2=16$ GeV$^2$ for different densities of nuclear medium and results have been compared with the available experimental data. The DAs and PDFs are found to modify substantially as a function of baryon density as compared to temperature and isospin asymmetry of the medium.

nucl-th↗

arXiv2024

Impact of finite volume on kaon, antikaon, and $ϕ$ meson masses and decay width in asymmetric strange hadronic matter

In the present work, we investigate the impact of finite volume on the in-medium properties of kaons ($K^+$, $K^0$) and antikaons ($K^-$, $\bar{K^0}$), and $ϕ$ mesons in the isospin asymmetric strange hadronic medium at finite density and temperature. We use the chiral SU(3) hadronic mean-field model, which accounts for the interactions between baryons through the exchange of scalar ($σ, ζ, δ$) and vector ($ω$, $ρ$, $ϕ$) fields. To investigate the effects of finite volume, we apply the multiple reflection expansion (MRE) technique for calculations of the density of states. The non-strange scalar field $σ$ shows significant variation in an asymmetric medium, while the strange scalar field $ζ$ shows good dependency in the strange medium. We use the medium-modified masses of kaons and antikaons calculated using the chiral SU(3) model to obtain the masses and decay width of $ϕ$ mesons in finite volume hadronic medium. To obtain the masses and decay widths of $ϕ$ mesons, an effective Lagrangian approach with $ϕ$$K$$\bar{K}$ interactions at one-loop level is used in the present work. We obtain the effective masses and decay widths in the finite volume matter, for the spherical geometry of the medium with Neumann and Dirichlet boundary conditions as well as for the cubic geometry. The finite volume effects are found to be appreciable at high baryon densities.

hep-ph↗

arXiv2024

Simulation of high-speed impact of surfactant-laden drops

We develop a computational model to simulate the immediate post-impact spreading behaviour of surfactant-laden drops that impact a flat and solid surface. The model is built on the InterFoam solver (OpenFOAM software), which uses the volume-of-fluid method to solve the Navier-Stokes equations. In order to incorporate surfactant in the bulk and on the interface, we make numerous modifications and extensions, such as coupling the volume-of-fluid method with a level-set method. Simulations demonstrate the accumulation of surfactant in the vicinity of the moving contact line, especially during the formation of the rim. Gradients of surfactant at the liquid-air interface lead to Marangoni forces that oppose the drop spreading, while high-velocity impacts reduce the overall surface tension and increase the magnitude of Marangoni forces. Both of these phenomena, which tend to reduce the maximum spreading, are highly dependent on the surfactant properties. Our computational methodology expands the potential for utilising Computational Fluid Dynamics to model complex interfacial flows that involve surfactants, leading to various opportunities in the future.

physics.flu-dyn↗

arXiv2024

Thermodynamic properties and phase diagram of quark matter within non-extensive Polyakov chiral SU (3) quark mean field model

In the present work, we apply Tsallis non-extensive statistics to study the thermodynamic properties and phase diagram of quark matter in the Polyakov chiral SU(3) quark mean field model. Within this model, the properties of the quark matter are modified through the scalar fields $σ, ζ, δ, χ$, the vector fields $ω, ρ$, $ϕ$, and the Polyakov fields $Φ$ and $\barΦ$ at finite temperature and chemical potential. Non-extensive effects have been introduced through a dimensionless parameter $q$ and the results are compared to the extensive case ($q\rightarrow1$). In the non-extensive case, the exponential in the Fermi-Dirac (FD) function is modified to a $q$-exponential form. The influence of $q$ parameter on the thermodynamic properties: pressure, energy, and entropy density as well as trace anomaly is investigated. The speed of sound and specific heat with non-extensive effects is also studied. Furthermore, the effect of non-extensivity on the deconfinement phase transition as well as the chiral phase transition of $u, d,$ and $s$ quarks is explored. We found that the critical end point (CEP), which defines the point in the $(T - μ)$ phase diagram where the order of the phase transition changes, shifts to a lower value of temperature, $T_{CEP}$, and a higher value of chemical potential, $μ_{CEP}$, as the non-extensivity is increased, i.e., $q>$1.

hep-ph↗

arXiv2023

$F$-thresholds of filtrations of ideals

In this article, we extend the notion of the $F$-thresholds of ideals to the $F$-thresholds for filtrations of ideals. The existence of $F$-thresholds of filtrations are established for various types of filtrations. Moreover, various necessary and sufficient conditions for finiteness of $F$-thresholds are given. We also give some effective upper bounds of the symbolic $F$-thresholds. A sufficient condition for symbolic $F$-splitting in terms of its symbolic $F$-threshold is given. We compute the symbolic $F$-thresholds of various determinantal ideals, $F$-König ideals, and many more.

math.AC↗

arXiv2023

Structural constraints on the emergence of oscillations in multi-population neural networks

Oscillations arise in many real-world systems and are associated with both functional and dysfunctional states. Whether a network can oscillate can be estimated if we know the strength of interaction between nodes. But in real-world networks (in particular in biological networks) it is usually not possible to know the exact connection weights. Therefore, it is important to determine the structural properties of a network necessary to generate oscillations. Here, we provide a proof that uses dynamical system theory to prove that an odd number of inhibitory nodes and strong enough connections are necessary to generate oscillations in a single cycle threshold-linear network. We illustrate these analytical results in a biologically plausible network with either firing-rate based or spiking neurons. Our work provides structural properties necessary to generate oscillations in a network. We use this knowledge to reconcile recent experimental findings about oscillations in basal ganglia with classical findings.

q-bio.NC↗

arXiv2023

Magnetic moments of decuplet baryons in asymmetric strange hadronic matter at finite temperature

In the present work we study the masses and magnetic moments of decuplet baryons in isospin asymmetric strange hadronic medium at finite temperature using chiral SU(3) quark mean field model. In the strange isospin asymmetric medium, the properties of baryons in chiral SU(3) mean field model are modified through the exchange of scalar fields $σ$, $ζ$ and $δ$ and the vector fields $ω$, $ρ$ and $ϕ$. The scalar-isovector field $δ$ and the vector-isovector field $ρ$ signifies the finite isospin asymmetry of the medium. We calculate the in-medium constituent quark masses and masses of decuplet baryons in asymmetric strange matter within the chiral SU(3) quark mean field model and use these as input in the constituent chiral quark model to calculate the in-medium magnetic moments of decuplet baryons for different values of isospin asymmetry and strangeness fraction of hot and dense medium. For calculating the magnetic moments of baryons, contributions of valence quarks, quark sea and orbital angular momentum of quark sea are considered in the calculations.

nucl-th↗

arXiv2023

Impact of non-zero strangeness on thermodynamics of finite volume quark matter

This paper investigates the impact of strangeness chemical potential and finite volume on QCD critical end point by employing a (2+1) flavored Polyakov quark meson model. Within the mean-field approximation, the model has been extended to study the effect of vector interactions on the thermodynamics of isospin-asymmetric quark matter. Susceptibilities of conserved charges like the quark and strangeness number are analyzed using Taylor's series expansion. The chiral phase transition boundary in the QCD phase diagram is found to be shifted towards higher values of the quark chemical potential ($μ_q$) and lower temperature (T) for decreasing system size. On the other hand, there is an opposite change to lower quark chemical potential and higher temperature for decreasing strangeness chemical potential.

nucl-th↗

arXiv2023

Data fusion for a multi-scale model of a wheat leaf surface: a unifying approach using a radial basis function partition of unity method

Realistic digital models of plant leaves are crucial to fluid dynamics simulations of droplets for optimising agrochemical spray technologies. The presence and nature of small features (on the order of 100$\mathrm{μm}$) such as ridges and hairs on the surface have been shown to significantly affect the droplet evaporation, and thus the leaf's potential uptake of active ingredients. We show that these microstructures can be captured by implicit radial basis function partition of unity (RBFPU) surface reconstructions from micro-CT scan datasets. However, scanning a whole leaf ($20\mathrm{cm^2}$) at micron resolutions is infeasible due to both extremely large data storage requirements and scanner time constraints. Instead, we micro-CT scan only a small segment of a wheat leaf ($4\mathrm{mm^2}$). We fit a RBFPU implicit surface to this segment, and an explicit RBFPU surface to a lower resolution laser scan of the whole leaf. Parameterising the leaf using a locally orthogonal coordinate system, we then replicate the now resolved microstructure many times across a larger, coarser, representation of the leaf surface that captures important macroscale features, such as its size, shape, and orientation. The edge of one segment of the microstructure model is blended into its neighbour naturally by the partition of unity method. The result is one implicit surface reconstruction that captures the wheat leaf's features at both the micro- and macro-scales.

math.NA↗

arXiv2023

Resurgence number of graded families of ideals

We define the resurgence and asymptotic resurgence numbers associated to a pair of graded families of ideals in a Noetherian ring. These notions generalize the well-studied resurgence and asymptotic resurgence of an ideal in a polynomial ring. We examine when these invariant are finite and rational. We investigate situations where these invariant can be computed via Rees valuations or realized as actual limits of well-defined sequences. We study how the asymptotic resurgence changes when a family is replaced by its integral closure. Many examples are given to illustrate that whether or not known properties of resurgence and asymptotic resurgence of an ideal would extend to that of a pair of graded families of ideals generally depends on the Noetherian property and finite generation of the Rees algebras of these families.

math.AC↗

arXiv2023

Axial-vector form factors of the light, singly and doubly charmed baryons in the chiral quark constituent model

The axial-vector form factors of the light, singly and doubly charmed baryons are investigated in the framework of $SU(4)$ chiral constituent quark model. The axial-vector form factors having physical significance correspond to the generators of the $SU(4)$ group with flavor singlet $λ^{0}$, flavor isovector $λ^{3}$, flavor hypercharge $λ^{8}$ and flavor charmed $λ^{15}$ combinations of axial-vector current at zero momentum transfer. In order to further understand the $Q^2$ dependence of these charges, we have used the conventionally established dipole form of parametrization.

hep-ph↗

arXiv2023

Powers of facet ideals of simplicial trees

In this article, we study the linearity of the minimal free resolution of powers of facets ideals of simplicial trees. We give a complete characterization of simplicial trees for which (some) power of its facet ideal has a linear resolution. We calculate the regularity of the $t$-path ideal of a perfect rooted tree. We also obtain an upper bound for the regularity of the $t$-path ideal of a rooted tree. We give a procedure to calculate the regularity of powers of facet ideals of simplicial trees. As a consequence of this result, we study the regularity of powers of $t$-path ideals of rooted trees. We pose a regularity upper bound conjecture for facet ideals of simplicial trees, which is as follows: if $Δ$ is a $d$-dimensional simplicial tree, then $\reg(I(Δ)^s) \leq (d+1)(s-1)+\reg(I(Δ))$ for all $s \geq 1$. We prove this conjecture for some special classes of simplicial trees.

math.AC↗

arXiv2023

Axial-vector charges of the spin $\frac{1}{2}^+$ and spin $\frac{3}{2}^+$ light and charmed baryons in the SU(4) chiral quark constituent model

Following the first clear evidence of the presence of intrinsic charm contribution in the proton, the axial-vector charges of the light and charmed baryons are investigated in the framework of $SU(4)$ chiral constituent quark model after including the explicit contributions from the $u\bar u $, $d\bar d $, $s\bar s $ and $c\bar c $ fluctuations. The axial-vector charges having physical significance correspond to the generators of the $SU(4)$ group with flavor singlet $λ^0$, flavor isovector $λ^3$, flavor hypercharge $λ^8$ and flavor charmed $λ^{15}$ combinations of axial-vector current at zero momentum transfer. In contemplation to further understand the $Q^2$ dependence of these charges, we have used the conventionally established dipole form of parametrization. The baryons considered here are the spin $\frac{1}{2}^+$ and spin $\frac{3}{2}^+$ multiplets decomposed further depending on the charm content of baryons.

hep-ph↗

arXiv2023

Effects of finite volume and magnetic fields on thermodynamic properties of quark matter and fluctuations of conserved charges

In the current work, we present the influence of finite volume and magnetic field on the thermodynamic properties of isospin asymmetric quark matter using the Polyakov loop extended chiral SU(3) quark mean field (PCQMF) model at finite chemical potential and temperature. Within the PCQMF model, we use the scalar and vector field values in mean-field approximation to obtain the thermodynamic properties: pressure density, entropy density and energy density. The susceptibilities of conserved charges for strongly interacting matter for different system sizes as well as for different values of the magnetic field have been studied. A sizable shift in phase boundary towards the higher values of quark chemical potential ($μ_q$) and temperature (T) has been observed for decreasing values of system volume as well as an opposite shift towards lower temperature and quark chemical potential for increasing magnetic field. We observe an enhancement in fluctuations of conserved charges in the regime of the transition temperature. These studies may have a significant role in understanding the thermodynamic observables extracted from heavy-ion collisions data.

hep-ph↗