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Sameer Ahmad Mir

Publications and source records attributed to Sameer Ahmad Mir.

11 recordsLinked to original sources
arXiv2026

Minimal-Length Deformations of Chiral Quark Matter in a 2+1-Flavor NJL Model

In this paper, a minimal-length inspired deformation of hot and dense chiral quark matter is formulated within a \(2+1\)-flavor Nambu-Jona-Lasinio framework. The deformation is based on a complete Jacobi-consistent three-dimensional quadratic GUP algebra and modifies the microscopic phase-space density of states while leaving the quasiparticle spectrum unchanged, leading to a thermodynamically closed mean-field theory with coupled light and strange gap equations. The analysis shows that ultraviolet phase-space suppression weakens dynamical chiral symmetry breaking, lowers the light and strange constituent masses, and shifts the light-sector chiral transition boundary, including its crossover and critical endpoint toward lower temperature and chemical potential. The numerical results are obtained from a single self-consistent solution of the coupled gap equations, and explicit endpoint comparisons show that the temperature-dependent and chemical-potential dependent results are mutually consistent. The result is a systematic effective-model study of how minimal-length inspired ultraviolet deformations reorganize coupled chiral dynamics and bulk quark-matter thermodynamics.

hep-ph↗
arXiv2026

Finite-Resolution Limits on Quantum Uniqueness

The Stone-von Neumann theorem makes canonical quantization unique only after one imposes strong continuity of the Weyl translation groups. We show that this continuity assumption cannot be certified by any finite-resolution interrogation of the Weyl relations. A finite protocol probes only finitely many phase-space displacements and bounded expectation values, thereby determining a protocol algebra \(C_S\) generated by a finitely generated subgroup of Weyl translations, but not the regularity of an extension to the full Weyl algebra. Using the polymer representation as a canonical non-regular representation, we prove that for every regular Weyl representation, every normal state, and every finite family of bounded protocol observables, a polymer state reproduces the same expectation values to arbitrary prescribed accuracy. Thus finite agreement with Schrödinger quantum mechanics does not operationally certify the regularity hypothesis entering uniqueness. The result does not assert physical equivalence between regular and polymer quantizations, it identifies where additional input, such as Hamiltonian dynamics, energy regularity, semiclassicality, or a continuum limit, is required to distinguish or select representations. In this precise sense, non-regular polymer kinematics are not excluded by finite Weyl data alone, a point of direct relevance to quantum-gravity motivated quantizations.

quant-ph↗
arXiv2026

Unified Functional-Holographic Theory of the QCD Critical End Point

We develop a thermodynamically consistent nonperturbative framework for equilibrium QCD criticality, unifying DSE quark propagation, FRG flow, and PNJL thermodynamics for coupled chiral/deconfinement order parameters. A holographic Maxwell-Chern-Simons sector supplies topological response; its topological susceptibility enters the FRG flow of the determinantal ('t Hooft) interaction, encoding axial-anomaly evolution across the phase diagram. At $μ_B=0$ we anchor to continuum-extrapolated lattice thermodynamics and conserved-charge susceptibilities through a lattice-calibrated Polyakov sector, enforcing exact thermodynamic identities by evaluating derivatives at the stationary grand-potential solution at each RG scale. Solving the coupled DSE-FRG-holographic system yields, at the present approximation level, an equilibrium critical end point at $T_{\mathrm{CEP}}\simeq130\text{--}135,\mathrm{MeV}$ and $μ_{B,\mathrm{CEP}}\simeq600,\mathrm{MeV}$, with quantified sensitivity to regulator, Polyakov-sector, and holographic-normalization choices. The critical region is organized by a nonperturbative map onto universal 3D Ising scaling variables, with anomalous-dimension effects absorbed into nonuniversal metric factors, yielding predictions for the hierarchy, nonmonotonicity, and sign structure of higher-order net-baryon cumulant ratios along smooth freeze-out trajectories and speed-of-sound softening. Comparisons to RHIC BES fluctuation measurements are qualitative consistency checks on correlated equilibrium trends and sign patterns, because finite size/lifetime, critical slowing down, baryon-number conservation, acceptance/efficiency corrections, net-proton-to-net-baryon conversion, and baryon transport can round or reshape experimental cumulants. The results provide a unified equilibrium baseline and controlled inputs for finite-size scaling and dynamical embeddings of heavy-ion data.

hep-ph↗
arXiv2026

Geometric Baryogenesis with Chiral-Time Equivalence

The asymmetry between matter and antimatter demands a cause as simple as it is profound. Here we show that a single geometric principle Chiral-Time Equivalence (CTE)-suffices to generate and correlate the required CP violation with the time orientation of the cosmos. Promoting the Immirzi parameter to a pseudoscalar Nambu-Goldstone field $Φ$, CTE fixes the leading operators: a shift-symmetric derivative portal $((\partial_μΦ)J^μ_{B-L}/M_*)$ that acts as a dynamical chemical potential in FRW, and a topological term $(Φ\,R\tilde R)$ that imprints parity on tensor modes. In thermal equilibrium this structure produces gravity-assisted leptogenesis, whose magnitude is set at the decoupling temperature by susceptibilities rather than by tuned departures from equilibrium. A fully flavored Boltzmann network with curvature sources captures flavor transfer and washout, while slow-roll and resonant regimes are established via thermodynamic and Kubo formulas. Consistency is secured by an EFT analysis (stability, perturbative unitarity, and BBN safety), and by explicit elimination of EC torsion and control of dCS birefringence in the small-coupling domain. The most striking prediction is a sign locking among $η_B$, tensor chirality $χ_T$, and the drift of $Φ$, together with a tri-observable relation that ties $η_B$ to cosmic birefringence $Δα$ and $χ_T$. Thus a single, symmetry-protected geometric origin renders the baryon excess testable by TB/EB correlations and stochastic-wave chirality, and calculable within a minimal, ultraviolet-anchored effective theory.

hep-ph↗
arXiv2026

Discrete \texorpdfstring{$θ$}{theta} Projection: A Gauge-Protected Solution to the Strong CP Problem Without Axions

We address the strong CP problem: why the physical QCD angle theta-bar must be extraordinarily small given the stringent bounds on the neutron electric dipole moment. Peccei-Quinn axion models can relax theta-bar dynamically, but rely on an approximate global symmetry expected to be violated by quantum gravity and face severe astrophysical and cosmological constraints. We propose Discrete theta Projection, an axionless, gauge-protected resolution obtained by gauging a finite cyclic subgroup $Z_N $of the $2π$ shift symmetry of theta. Coupling QCD to a compact, local and gapped topological sector orbifolds the path integral, identifying theta values that differ by $2π/N$ and admitting only instanton sectors whose topological charge lies in $Z_N$. In the large four-volume limit the vacuum energy becomes the lower envelope of the orbifold images, so the theory dynamically selects the branch closest to the CP-symmetric point, enforcing $|\barθ| \le π/N$ without assuming any prior smallness. Because the discrete shift is gauged, continuous renormalization of theta is forbidden; the construction can be formulated via higher-form/two-group structure with integer-quantized couplings fixed by anomaly inflow, ensuring radiative and gravitational stability and satisfying mixed gauge-gravity consistency conditions. The framework predicts a neutron EDM suppressed by $1/N$, no axion signatures, no domain-wall/isocurvature issues, and lattice diagnostics: piecewise-analytic theta dependence with cusps at odd fractions of the reduced period and a global curvature scaling as $1/N^2$. We provide the EFT construction, a nonperturbative proof of vacuum projection, a full anomaly analysis, and UV embeddings (including discrete clockwork chains) that generate large effective N while preserving integrality and consistency throughout.

hep-th↗
arXiv2026

Undecidability in Spacetime Geometry via the AdS/CFT Correspondence

Undecidability, a hallmark of Gödel incompleteness theorems, has recently emerged in quantum many-body physics through the spectral gap problem. We demonstrate how this logical limitation can be holographically transmitted to a class of gravitational theories via the AdS/CFT correspondence. By embedding a translationally invariant spin Hamiltonian with undecidable gap status into a large-N gauge theory, we generate an AdS dual in which the selection of dominant bulk saddle (Poincaré AdS or AdS soliton) is itself undecidable. Consequently, under standard semiclassical holographic assumptions, even determining which smooth spacetime geometry emerges from quantum gravity can be beyond the limits of computability.

hep-th↗
arXiv2025

Particle production in HRG with thermodynamically consistent EoS and partially deformable hadrons

In the present work, we analyze several strange as well as non-strange relative hadronic yields obtained in the ultra-relativistic heavy-ion collisions (URHIC) experiments over a wide range of center-of-mass collision energy ($\sqrt{s_{NN}}$). We invoke the formation of a hot and dense hadronic resonance gas (HRG) in the final stage following the URHIC. We use an earlier proposed thermodynamically consistent approach for obtaining the equation of state (EoS) of a HRG. It takes into account an important aspect of the hadronic interaction, viz., the hadronic hard-core repulsion, by assigning hard-core volumes to the hadrons, leading to an excluded volume (EV) type effect. We have invoked the bag model approach to assign hard-core volumes to baryons (antibaryons) while treating mesons to be point particles. We employ ansatz to obtain the dependence of the temperature (\textit{T}) and baryon chemical potential (BCP) of HRG system on the center-of-mass energy in URHIC. We also find strong evidence of a double freeze-out scenario, corresponding to baryons (antibaryons) and mesons, respectively. Strangeness (anti-strangeness) imbalance factor is also seen to play an important role in explaining the ratio of strange hadrons to the non-strange ones. The HRG model can explain the experimental data on various relative hadronic multiplicities quite satisfactorily over a wide range of $\sqrt{s_{NN}}$, ranging from the lowest RHIC energies to the highest LHC energies using one set of model parameters by obtaining the best theoretical fits to the experimental data using the minimum $χ^{2}$/dof method.

hep-ph↗
arXiv2024

Collision Energy Dependence of Particle Ratios and Freeze-out Parameters in Ultra Relativistic Nucleus Nucleus Collisions

This work investigates the thermo-chemical freeze-out condition of the multi-component hot and dense hadron resonance gas (HRG) formed in the ultra-relativistic nucleus-nucleus collisions (URNNC). The van der Waals (VDW) type model used in the present analysis incorporates the repulsive as well as attractive interactions among the hadrons. The baryons (antibaryons) are treated as incompressible objects. Using this theoretical approach the values of the model freeze-out parameters of the system are extracted over a wide range of collision energy by analyzing experimental data on like-mass antibaryon to baryon ratios. The same set of parameters is found to explain the energy dependence of several other particle ratios quite satisfactorily. We find that the horn-like structures seen in the ratios of strange particles to pions as a function of the collision energy cannot be explained by the VDW-HRG model alone without considering the strangeness imbalance effect in the system. We have compared our freeze-out line with those obtained earlier. The correlation between the $\bar{p}/p$ and $K^-/K^+$ ratios is also examined.

hep-ph↗
arXiv2024

Relative Hadron Yields in HRG With Medium Modification

In the framework of a constituent quark mass model, the modified baryon masses are incorporated into the hadron resonance gas (HRG) based analysis of the like mass particle ratios in ultra relativistic nucleus-nucleus collisions (URNNC) over a wide range of collision energy. In addition we have incorporated an essential feature of the hadronic interaction at short distance, i.e. the hard-core repulsion by using the standard excluded volume type approach. We have extracted the chemical freeze-out conditions. The resulting freeze-out line in our case is compared with those obtained earlier using different model approaches. The correlation between $k^{-}/k^{+}$ and $\bar p/p$ ratios is also studied.

hep-ph↗
arXiv2024

Hadron Production in Ultra-relativistic Nuclear Collisions and Finite Baryon-Size Effects

We investigate relative hadron yield production of various like and unlike mass particles in ultra-relativistic heavy ion collisions by employing a statistical thermal model with finite-sized baryons (antibaryons) to imitate the hard-core repulsive interactions leading to the excluded volume type effect. A strong evidence of strangeness suppression relative to the non-strange ones, mainly pions, particularly at higher energies is also observed. This study also indicates that at chemical freeze-out the particle ratios and strangeness suppression in the system obtained theoretically are sensitive to baryonic (antibaryonic) hard-core radius ($r_B$). A comparison with earlier analysis involving the strangeness suppression effect is made where baryons and antibaryons were treated as point-like particles. The available experimental data showing energy dependence of various particle ratios are well described throughout the range of centre-of-mass energy ($\sqrt{s_{NN}}$). The value of hard-core radius between 0.76 to 0.79 fm is found to fit the data quite well using $χ^{2}$ minimization technique. Two different chemical freeze-out stages are found where the earlier one belongs to baryonic (hyperonic), antibaryonic (antihyperonic) states and the later one to mesonic degrees of freedom.

hep-ph↗