sPNP: Mogging MOG? If not, they will likely just add a new particle

@philphi.bsky.social

sPNP: Explaining Recent Dark Matter Observations with Fisher Curvature

Recent observational studies have introduced compelling challenges to standard Cold Dark Matter (CDM) cosmology and its modified-gravity alternatives. Two particularly striking results are: the unexpectedly strong large-scale clustering of diffuse dwarf galaxies reported by Zhang et al. (2025), and the discovery of HI-rich galaxies requiring extremely high (~5σ) halo concentrations discussed by Kong & Yu (2025). While these findings have been interpreted as strong evidence for self-interacting dark matter (SIDM), they present significant difficulties for modified gravity frameworks such as MOND and MOG. In contrast, the sPaceNPilottime (sPNP) framework offers a natural and unified explanation for both, leveraging its deeper informational-geometric foundation.

Limits of MOND and MOG

MOND (MOdified Newtonian Dynamics) was originally designed to explain flat galactic rotation curves by introducing a phenomenological acceleration scale, a0, below which Newtonian dynamics is modified. MOG (MOdified Gravity, or Scalar-Tensor-Vector Gravity) extends this idea, incorporating additional scalar and vector fields to address galaxy cluster dynamics and cosmological expansion.

Despite their successes at galactic scales, both MOND and MOG face conceptual and empirical limitations:

Phenomenological, not foundational: MOND lacks a deeper underlying principle for why a0 should exist or how it integrates with early-universe cosmology. MOG introduces extra fields but offers no unifying variational principle or unique renormalization group flow tying these fields to quantum or cosmic structure.

Clustering and concentration puzzles: Neither theory predicts the anomalous large-scale clustering of low-mass dwarf galaxies nor naturally accounts for high-concentration (core-collapse-like) halos in HI-rich galaxies without introducing additional ad hoc parameters.

Thus, while MOND and MOG can reproduce flat rotation curves, they fail to accommodate new empirical evidence that goes beyond purely local galactic dynamics.

The sPNP Framework: A Unified Approach

sPNP begins with a single variational principle: the Jacobi action deformed by a Fisher information term. The resulting action is

S[q] = ∫ sqrt{2 (E - V(q)) * g_ij(q) * dq^i/dσ * dq^j/dσ} dσ + λ' ∫ [g^ij * ∂_i ρ * ∂_j ρ / ρ] d^m q

where ρ is the probability density on configuration space, and λ' is the Fisher coupling. Varying this action introduces a geometric potential term Q, intimately connected to the curvature of configuration space and the dynamics of the δR field.

This construction leads to multiple key phenomena using only one coupling λ':

Flat rotation curves: The quantum-geometric potential Q (∇²δR) modifies the effective gravitational pull at large radii, yielding a constant orbital velocity without additional dark matter.

Primordial perturbations and CMB structure: The same δR field that controls galactic dynamics also generates adiabatic, nearly scale-invariant perturbations during a quasi–de Sitter epoch, explaining phase-coherent CMB acoustic peaks.

Late-time accelerated expansion: The homogeneous mode of δR, driven by a tachyonic potential, naturally acts as dark energy, providing late-time cosmic acceleration with equation of state w ≈ -1.

Clustering of Diffuse Dwarfs: A Natural Consequence of Fisher Geometry

The strong large-scale clustering of diffuse dwarf galaxies, seen by Zhang et al., defies ΛCDM expectations since low-mass halos should exhibit weak bias. SIDM has been proposed to explain this via altered halo assembly histories. However, in sPNP, this effect emerges directly from configuration-space geometry.

The δR field encodes quantum-geometric stress (via ∇²δR), modifying the effective potential wells even at low masses. Systems that preserve stronger Fisher-curvature memory — such as early-forming, diffuse dwarfs — naturally prefer high-density environments, leading to an enhanced clustering signal. This assembly bias does not require any particle interactions or new cross-sections; it follows deterministically from the same Fisher-deformed Jacobi action that governs other galactic and cosmological behaviors.

HI-Rich Galaxies and Geometric Core Collapse

Kong & Yu’s observation of HI-rich galaxies requiring extremely high halo concentrations (~5σ above NFW expectations) suggests a core-collapse phenomenon reminiscent of SIDM scenarios. SIDM explains this via collisional thermalization in dense cosmic nodes, leading to denser inner cores.

Within sPNP, an analogous effect arises through nonlinear evolution of δR in dense environments. In cosmic nodes, the δR field undergoes geometric focusing, enhancing local curvature and steepening inner halo profiles. This "geometric core collapse" mimics the observed high-concentration signatures without invoking particle-level self-interactions. Instead, it results from the same non-linear Fisher information dynamics embedded in the universal variational principle.

Predictive Power and Unity

A major strength of sPNP is its extreme economy of assumptions. Unlike SIDM (which introduces a cross-section σ/m) or MOG (which introduces several free functions for scalar and vector fields), sPNP relies on a single parameter λ'. This coupling is already fixed by other observations (e.g., flat rotation curves and dark energy) and thus cannot be freely tuned to match dwarf clustering or core-collapse data. The resulting predictions are not phenomenological fits but genuine consequences of the unified framework.

Furthermore, observational tests can distinguish sPNP from SIDM and modified gravity scenarios. For instance, sPNP predicts steeper-than-NFW inner slopes (without true cores), scale-dependent clustering biases tied to δR amplitude, and specific corrections to the CMB Boltzmann hierarchy via δR-induced source terms S_Q(k, τ).

Conclusion

While MOND and MOG elegantly address certain galaxy-scale puzzles, they struggle to incorporate new large-scale and internal halo structure observations in a self-consistent cosmological picture. In contrast, sPNP subsumes these phenomena naturally, explaining both the unexpected clustering of dwarf galaxies and the extreme inner halo concentrations of HI-rich systems using a single geometrically rooted mechanism. The same δR field and Fisher coupling λ' unify galaxy dynamics, structure formation, cosmic acceleration, and CMB perturbations, providing a deeper theoretical coherence unmatched by phenomenological modifications of gravity.

Thus, sPNP stands as not only a competitor but a conceptual successor to MOND and MOG; offering a unified, predictive, and fundamentally geometric understanding of dark sector phenomenology.

philphi.bsky.social
Phil

@philphi.bsky.social

Fisher Curvature, PHILosophy. "Philo" means "loving" or "friend". D[R S] ≠ 0. sPaceNPilottime

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