Cosmological Hierarchy Research Articles

More on black holes perceiving the dark dimension

In the last two years, the dark dimension scenario has emerged as focal point of many research interests. In particular, it functions as a stepping stone to address the cosmological hierarchy problem and provides a colosseum for dark matter contenders. We reexamine the possibility that primordial black holes (PBHs) perceiving the dark dimension could constitute all of the dark matter in the Universe. We reassess limits on the abundance of PBHs as dark matter candidates from γ-ray emission resulting from Hawking evaporation. We reevaluate constraints from the diffuse γ-ray emission in the direction of the Galactic Center that offer the best and most solid upper limits on the dark matter fraction composed of PBHs. The revised mass range that allows PBHs to assemble all cosmological dark matter is estimated to be 1015≲MBH/g≲1021. We demonstrate that, due to the constraints from γ-ray emission, quantum corrections due to the speculative memory burden effect do not modify this mass range. We also investigate the main characteristics of PBHs that are localized in the bulk. We show that PBHs localized in the bulk can make all cosmological dark matter if 1011≲MBH/g≲1021. Finally, we comment on the black holes that could be produced if one advocates a space with two boundaries for the dark dimension. Published by the American Physical Society 2024

Probing the dark dimension with Auger data

By combining swampland conjectures with observational data, it was recently pointed out that our universe could stretch off in an asymptotic region of the string landscape of vacua. Within this framework, the cosmological hierarchy problem (i.e. the smallness of the cosmological constant in Planck units: Λ∼10−122MPl4) can be naturally resolved by the addition of one mesoscopic (dark) dimension of size ∼λΛ−1/4∼1μm. The Planck scale of the higher dimensional theory, MUV∼λ−1/3Λ1/12MPl2/3∼1010GeV, is tantalizingly close to the energy above which the Telescope Array (TA) and the Pierre Auger collaborations found conclusive evidence for a sharp cutoff of the flux of ultra-high-energy cosmic rays (UHECRs). It was recently suggested that since physics becomes strongly coupled to gravity beyond MUV, universal features deep-rooted in the dark dimension could control the energy cutoff of the source spectra ∝E−γexp(−E/MUV), where E is the cosmic ray energy and γ a free parameter. Conversely, in the absence of phenomena inborn within the dark dimension, we would expect a high variance of the cosmic ray maximum energy Emax characterizing the source spectra ∝E−γexp(−E/Emax), reflecting the many different properties inherent to the most commonly assumed UHECR accelerators. The most recent analysis of Auger and TA data exposed strong evidence for a correlation between UHECRs and nearby starburst galaxies, with a global significance post-trial of 4.7σ. Since these galaxies are in our cosmic backyard, the flux attenuation factor due to cosmic ray interactions en route to Earth turns out to be negligible. This reasoning implies that for each source, the shape of the observed spectrum should roughly match the emission spectrum by the starburst, providing a unique testing ground for the dark dimension hypothesis. Using Auger data, we carry out a maximum likelihood analysis to characterize the shape of the UHECR emission from the galaxies dominating the anisotropy signal. We show that the observed spectra from these sources could be universal only if λ≲10−3.

The dark universe: Primordial black hole ⇋ dark graviton gas connection

We study the possible correspondence between 5-dimensional primordial black holes and massive 5-dimensional KK gravitons as dark matter candidate within the recently proposed dark dimension scenario that addresses the cosmological hierarchy problem. First, we show that in the local universe a population of 5-dimensional black holes with MBH∼7×1013g would be practically indistinguishable from a KK tower of dark gravitons with mDM∼50keV. Second, we connect the mass increase of 5-dimensional black holes and the related temperature decrease with the cooling of the tower of massive spin-2 KK excitations of the graviton. The dark gravitons are produced at a mass ∼1−50GeV and the bulk of their mass shifts down to roughly 1−100keV today. The cooling of the system proceeds via decay to lighter gravitons without losing much total mass density, resembling the intra-tower decays that characterize the cosmological evolution of the dynamical dark matter framework. We associate the intra-tower decays of the graviton gas with the black hole growth through accretion. We also discuss that the primordial black hole ⇋ dark graviton gas connection can be nicely explained by the bound state picture of black holes in terms of gravitons.

Dark dimension, the swampland, and the origin of cosmic rays beyond the Greisen-Zatsepin-Kuzmin barrier

Very recently, it was pointed out that when basic ideas of the Swampland program are combined with the cosmological hierarchy problem (i.e. the smallness of the dark energy in Planck units) and together are confronted to experiment lead to the prediction of the existence of a single extra-dimension (dubbed the dark dimension) with characteristic length-scale in the micron range. We propose a feasible test procedure to probe the dark dimension using the highest energy cosmic rays.

Cosmic eggs to relax the cosmological constant

In theories with extra dimensions, the cosmological hierarchy problem can be thought of as the unnaturally large radius of the observable universe in Kaluza-Klein units. We sketch a dynamical mechanism that relaxes this. In the early universe scenario we propose, three large spatial dimensions arise through tunneling from a `cosmic egg', an effectively one-dimensional configuration with all spatial dimensions compact and of comparable, small size. If the string landscape is dominated by low-dimensional compactifications, cosmic eggs would be natural initial conditions for cosmology. A quantum cosmological treatment of a toy model egg predicts that, in a variant of the Hartle-Hawking state, cosmic eggs break to form higher dimensional universes with a small, but positive cosmological constant or quintessence energy. Hence cosmic egg cosmology yields a scenario in which the seemingly unnaturally small observed value of the vacuum energy can arise from natural initial conditions.

Life's organization between matter and form: Neo-Aristotelian approaches and biosemiotics.

In this paper, I discuss the neo-Aristotelian approaches, which usually reinterpret Aristotle's ideas on form and/or borrow the notion of formal cause without engaging with the broader implications of Aristotle's metaphysics. In opposition to these approaches, I claim that biosemiotics can propose an alternative view on life's form. Specifically, I examine the proposals to replace the formal cause with gene-centrism, functionalism, and structuralism. After critically addressing these approaches, I discuss the problems of reconciling Aristotelianism with the modern view of life's organization. I claim that the notion of the final cause proposes a cosmological hierarchy and that this is the main problem with applying the formal cause to biology. An alternative categorization of conceptualizing life's form involves (1) the processual identity, (2) relational property clusters, and (3) context-dependent transmission of representational units. The third category points to a semiotic basis of the form of life. In this context, I offer to readjust the focus of the problem of matter-form duality by pointing out that form is primarily an issue of the subject-object relation. Biosemiotics helps to understand the constructive role of symbolic representation in living systems, which is crucial to extend the analysis of the form from cognitive representations to external phenomena. Emergence of subjectivity and perspectivity of interactions are key elements to bridge the form and actual processes within a non-hylomorphic account. To demonstrate transitions from the physical influence of shapes to the organic recognition of forms, I address the biological studies on the synchronization of coincidental inputs and enzyme specificity.

Fear and learning in medieval Islam

In this article I argue that a specific experience of fear was adopted by the Islamic scholarly class (ulema) from the mid-tenth century onwards as an affective descriptor of their profession. This fear - khashya, which I translate here as 'dread' - appears in the Qur'an as an apprehensive emotion that those who possess knowledge feel towards God. In modern scholarship, it has often been cited as a term used by scriptural and mystical commentators to explain proper piety, usually figured as one of several kinds of fear falling under the broader term khawf. In his commentary on Abu Isma'il al-Ansari's celebrated text of mystical terminology, Manazil al-sa'irin, Ibn Qayyim al-Jawziyya distinguishes khashya from khawf, citing the Qur'an in order to cast the latter as a baser experience of fear characteristic of common believers. Ibn al-Qayyim argues that it is exclusively the ulema who experience khashya, for only they enjoy intimate knowledge of God imparted by their erudition. While otherwise absent from the Manazil's commentary tradition, this argument appears prominently across works of scholarly ethics (adab) authored by ulema living from the mid-tenth century through Ibn al-Qayyim's lifetime, almost always in reference to the intellectual pursuits that they believed afforded them a unique relationship with God. Attended by a semantic shift in Arabic lexicography favoring this interpretation of khawf and khashya, by the tenth century the affectively resonant language of dread became a pervasive way the ulema justified the social and cosmological hierarchy of Muslims over which they claimed to preside.

Festina lente:1 EFT constraints from charged black hole evaporation in de Sitter

In the Swampland philosophy of constraining EFTs from black hole mechanics we study charged black hole evaporation in de Sitter space. We establish how the black hole mass and charge change over time due to both Hawking radiation and Schwinger pair production as a function of the masses and charges of the elementary particles in the theory. We find a lower bound on the mass of charged particles by demanding that large charged black holes evaporate back to empty de Sitter space, in accordance with the thermal picture of the de Sitter static patch. This bound is satisfied by the charged spectrum of the Standard Model. We discuss phenomenological implications for the cosmological hierarchy problem and inflation. Enforcing the thermal picture also leads to a heuristic remnant argument for the Weak Gravity Conjecture in de Sitter space, where the usual kinematic arguments do not work. We also comment on a possible relation between WGC and universal bounds on equilibration times. All in all, charged black holes in de Sitter should make haste to evaporate, but they should not rush it.2

Electroweak relaxation of cosmological hierarchy

A simple model for the late-time cosmic acceleration problem is presented in the Starobinsky inflation with a negative bare cosmological constant as well as a nonminimal coupling to the Higgs boson. After electroweak symmetry breaking, the Starobinsky inflaton has been frozen until very recently, becoming a thawing quintessence, and a comparable magnitude to the observed dark energy density can be achieved without fine-tuning. Our proposal essentially reduces the cosmological constant problem into the electroweak hierarchy problem, and its late-time behaviour is also consistent with the recently proposed swampland criteria.

Remarks on scale separation in flux vacua

We argue that the Maldacena-Nunez no-go theorem excluding Minkowski and de Sitter vacua in flux compactifications can be extended to exclude anti-de Sitter (AdS) vacua for which the Kaluza-Klein scale is parametrically smaller than the AdS length scale. As a practical application of this observation we demonstrate that the mechanism to resolve O6 singularities in massive type IIA at the classical level is likely not to occur in AdS compactifications with scale separation. We furthermore remark that a compactification to four observable dimensions implies a large cosmological hierarchy.

Discrete Scale Relativity and SX Phoenicis Variable Stars

Discrete Scale Relativity proposes a new symmetry principle called discrete cosmological self-similarity which relates each class of systems and phenomena on a given Scale of nature’s discrete cosmological hierarchy to the equivalent class of analogue systems and phenomena on any other Scale. The new symmetry principle can be understood in terms of discrete scale invariance involving the spatial, temporal and dynamic parameters of all systems and phenomena. This new paradigm predicts a rigorous discrete self-similarity between Stellar Scale variable stars and Atomic Scale excited atoms undergoing energy-level transitions and sub-threshold oscillations. Previously, methods for demonstrating and testing the proposed symmetry principle have been applied to RR Lyrae, δ Scuti and ZZ Ceti variable stars. In the present paper we apply the same analytical methods and diagnostic tests to a new class of variable stars: SX Phoenicis variables. Double-mode pulsators are shown to provide an especially useful means of testing the uniqueness and rigor of the conceptual principles and discrete self-similar scaling of Discrete Scale Relativity. These research efforts will help theoretical physicists to understand the fundamental discrete self-similarity of nature, and to model both stellar and atomic systems with one unified physics.

Turning the World Upside Down in 1 Corinthians 15: Apocalyptic Epistemology, the Resurrected Body and the New Creation

This article shows how Paul’s apocalyptic epistemology in 1 Corinthians 2 relates to an issue of ontology that arises in 1 Corinthians 15 (i.e., the nature of the resurrected body). Using the psychikon/pneumatikon terminology in both contexts, Paul’s rhetoric in 1 Corinthians 15 turns the cosmological hierarchy held to by ‘some’ in his audience upside down. Paul argues that the fleshly human body, rather than being at the bottom of a cosmological hierarchy with no place in the afterlife, will be elevated by God to the level of what will be redeemed/transformed in the new creation. This, in turn, suggests a definite material continuity between ‘this age’ and the new creation and that the discontinuity between them does not have to do with fleshly existence per se, but rather with how Sin has corrupted our current fleshly existence. The article concludes by suggesting that Paul’s rhetoric in this chapter ought to shape our contemporary eschatological imagination in a particular way. It should compel us not only to imagine the redemption of the material composing our body at death, but also the redemption of our body’s unfolding history along with the unfolding history of the cosmos.

From Delos to Delphi: A Literary Study of the Homeric Hymn to Apollo

This detailed literary and rhetorical analysis of the Homeric Hymn to Apollo treats the poem as a unified work of art in which sophisticated poetic craftsmanship is put to the service of serious ethical thought. By means of parallels from Homer, Hesiod, and other Homeric hymns, as well as from later epideictic poetry and prose, the author seeks to show that the poet of the Hymn follows a coherent ''program'' whose intention is to praise Apollo from his birth on humble Delos to his establishment in a position of glory at Delphi. At the same time, the ''Delian'' and ''Pythian'' portions of the hymn are linked by a complex network of ideas bearing on the ethos of Apollo and the nature of his Delphic oracle. The study takes into account previous scholarship on the Hymn and provides appendices on ''The Question of Unity'' and ''The Cosmological Hierarchy and Apollo's Timai''.

Kingship and Sacrifice: Ritual and Society in Ancient Hawaii

Valeri presents an overview of Hawaiian religious culture, in which hierarchies of social beings and their actions are mirrored by the cosmological hierarchy of the gods. As the sacrifice is performed, the worshipper is incorporated into the god of his class. Thus he draws on divine power to sustain the social order of which his action is a part, and in which his own place is determined by the degree of his resemblance to his god. The key to Hawaiian society-and a central focus for Valeri-is the complex and encompassing sacrificial ritual that is the responsibility of the king, for it displays in concrete actions all the concepts of pre-Western Hawaiian society. By interpreting and understanding this ritual cycle, Valeri contends, we can interpret all of Hawaiian religious culture.

Ezekiel's Vision Seen Through the Eyes of a Philosophic Mystic

Ezekiel's Vision Seen Through the Eyes of a Philosophic Mystic