Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2609.26834

Twin Universes and Bimetric Gravity: From Sakharov's Cosmological Symmetry to Modern Speculations on Negative Mass

Jean-Pierre Luminet
View original source ↗Read source document ↗Export metadata ↓

Abstract

We review the conceptual and theoretical status of twin-universe models, from Sakharov's early ideas on baryogenesis, CPT symmetry, and reversed arrows of time to recent quantum-cosmological scenarios involving pair-created entangled universes. Particular attention is given to the distinction between Sakharov-type cosmological symmetry, modern bimetric theories of gravity, and speculative models involving negative mass sectors. We summarize the main consistency conditions faced by bimetric gravity, including the Boulware-Deser ghost, Higuchi-type bounds, covariant conservation laws, and no-go results for positive- and negative-mass sectors. We then examine the Janus cosmological model and related black-hole replacement proposals, emphasizing the difference between heuristic twin-universe narratives and fully specified relativistic field theories. We argue that while twin-universe ideas remain a fertile framework for questions about the arrow of time, matter-antimatter asymmetry, and the quantum origin of the universe, models combining bimetric gravity, negative mass, dark-sector phenomenology, and alternatives to Kerr black holes face a substantial burden of mathematical and observational proof.

Explore related subjects

physics.gen-phgr-qc

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Jean-Pierre Luminet. 2026-09-21. Twin Universes and Bimetric Gravity: From Sakharov's Cosmological Symmetry to Modern Speculations on Negative Mass. https://arxiv.org/abs/2609.26834

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Evaluation of uncertainties in the estimates of correlated variables as the elemental-isotopic-abundances: properties of corresponding-indirect-measurement-system-specific-relationships

Isotopic-abundances of any multi-(N)-isotopic-element (E) are interdependent and therefore needed to be measured indirectly from their rather accurately-measurable (N-1) abundance-ratios. ... Even, corresponding-atomic-weight (A_E) is determined by translating the estimated-ratios into the desired-estimate via concerned-input(s)-output-system-specific-relationship (SSR). However, how good the output-estimates y_d(s) and a_E should represent their desired-true-values Y_d(s) and A_E be indicated by the respective uncertainties e_d^Y (s) and e_E^A only; i.e. correct-knowledge of even the output-uncertainties be indispensable for the desired-indirect-measurements. Usually, by assuming the lab-established-(input)-uncertainty(s) as u_m(s) to be accidental-in-nature, a measure of any-corresponding-non-correlated-variable-specific-output-uncertainty is obtained by the popular-error-propagation-law. And, any-correlated-variable as the isotopic-abundance-Y_d-specific-output-uncertainty e_d^Y is evaluated by incorporating additional-(correlation)-correction-factor(s) in the error-propagation-formula, i.e. correlation is being assumed as an output-uncertainty-governing-parameter. However, it is here clarified that: (i) the output-uncertainty e_d^Y (or even e_E^A) should, like the corresponding-output-estimate y_d (or a_E) itself, be independent of whether the isotopic-abundances are correlated; and: (ii) any output-uncertainty e should actually be the corresponding-SSR-governed-systematic-parameter, irrespective of whether the input-uncertainty(s) u_m (s) be purely-random-in-nature. That-is, like the non-correlated-variables-specific-SSRs discussed elsewhere, any isotopic-variable-specific-SSR should be bracketed with certain input(s)-to-output-variation-parameter(s) [MF]_m^d (s) which really prefix(s), for given the input-uncertainty(s) u_m (s), the corresponding-output-uncertainty ...

physics.gen-ph↗
arXiv2026

Yukawa coupling and one loop inflation in the light of CMB

The one loop inflation stemming from the superstring theory and associated Yukawa coupling arising from supersymmetric interactions is examined with CMB. The Yukawa coupling can exist beyond standard model particle physics sector. The tensor-to-scalar ratio of the loop inflation is found consistent with the recent CMB results for the Yukawa coupling from cosmology. The alternative constraint on the Yukawa coupling from loop inflation may play a crucial role in validating inflationary model originating from supersymmetry and string theory. The outcomes of the study may be helpful in the phenomenological realisation of string theory.

physics.gen-ph↗
arXiv2026

Phase Encoding of Genuine Three-Body Interactions in a Relativistic Dirac System in $1+1$ Dimensions

We show how genuine three-body phase information can enter the invariant mass of a relativistic three-particle Dirac system in $(1+1)$ dimensions. As a solvable reference system, we consider the Sakamoto--Munakata--Ino model with pairwise contact interactions $g_{ij}(1-α_iα_j)δ(x_i-x_j)$. These singular interactions can be transferred into sector-dependent phases and matching conditions by a discontinuous unitary transformation. Although the explicit contact terms are thereby removed, the nonzero constituent-mass operator is rotated and retains nontrivial spectral information. We introduce a genuine three-body holonomy generated by $Q_3=α_1α_2α_3$. The kinetic and pair-interaction parts commute with $Q_3$, while the constituent-mass operator anticommutes with it. Consequently, the massless system separates into the $Q_3=\pm1$ sectors, which acquire opposite holonomy phases $e^{\pm iθ_3}$, whereas nonzero constituent masses mix the two sectors. This phase-sector-mixing mechanism makes the relative three-body phase dynamically accessible to the bound-state spectrum and establishes an operator-level mechanism through which the three-body holonomy generates a $θ_3$ dependence of the physical three-body invariant mass. We further emphasize that the topological three-body holonomy is not automatically equivalent to a bare triple-contact potential; such an equivalence requires a regulated self-adjoint realization and a compatible interaction-dependent boost satisfying the Poincaré algebra. The resulting framework therefore connects genuine three-body phase information to the mass spectrum of a relativistic composite system while clearly separating the controlled holonomy construction from the unresolved short-distance triple-contact realization.

physics.gen-ph↗