Primordial Matter Research Articles

Superradiant axion clouds around asteroid-mass primordial black holes

We analyze the dynamics and observational signatures of axion clouds formed via the superradiant instability around primordial black holes, focusing on the mass range 1014 - 1018 kg where the latter may account for all the dark matter.We take into account the leading effects of axion self-interactions, showing that, even though these limit the number of axions produced within each cloud,a large number of superradiant axions become free of the black hole's gravitational potential and accumulate in the intergalactic medium or even in the host galaxy, depending on their escape velocity. This means that primordial black hole dark matter may lead to a sizeable astrophysical population of non-relativistic axions, with masses ranging from 0.1 eV to 1 MeV, depending on the primordial black hole mass and spin.We then show that if such axions couple to photons their contribution to the galactic and extragalactic background flux, mainly in the X-ray and gamma-ray band of the spectrum, is already beyond current observational limits for a large range of parameters that are, therefore, excluded. We finish by showing the prospects of the Athena X-ray telescope to further probe this co-existence of primordial black holes and axions.

Dark Matter Dilution Mechanism through the Lens of Large-Scale Structure.

Entropy production is a necessary ingredient for addressing the overpopulation of thermal relics. It is widely employed in particle physics models for explaining the origin of dark matter. A long-lived particle that decays to the known particles, while dominating the universe, plays the role of the dilutor. We point out the impact of its partial decay to dark matter on the primordial matter power spectrum. For the first time, we derive a stringent limit on the branching ratio of the dilutor to dark matter from large scale structure observation using the sloan digital sky survey data. This offers a novel tool for testing models with a dark matter dilution mechanism. We apply it to the left-right symmetric model and show that it firmly excludes a large portion of parameter space for right-handed neutrino warm dark matter.

Quantum-Relativistic Properties of the Space-Time Bubbles and Their Evolution in a Multi-Bubble Universe

The quantum-relativistic properties of space-time bubbles introduced in the recently proposed multi-Bubbles Universe model have been studied and deepened in the framework of the electromagnetic Bridge theory. In this context, it is shown how the space-time fabric of the emerging universe and the primordial matter contained in it, can be considered the final result of the decay of a pre-universe formed by a BEC of neutral Planck bosons hidden under the space-time horizon, having the characteristics of balancing gravitons associated with the potential energy of the vacuum defined as the field of nothingness. The estimated mass of the Planck boson is compatible with the smallest of the Kaluza-Klein graviton with an energy mass of 2.68 TeV, this value allows to estimate the limit of the Planck energy scale characterized by a lepton particle with a rest mass of 1.27 TeV. It is also shown as an ancient multi-bubble universe obtained by the decay of a pre-universe redshifted nowadays at 2.725 K, provides a Planck blackbody spectrum perfectly in agreement with the cosmic microwave background radiation of our universe measured by the COBE satellite.

Primordial black holes and secondary gravitational waves produced by S-dual inflation model

<sec>It is discussed in this work to produce primordial black hole (PBH) dark matter (DM) and scalar induced secondary gravitational waves by using the enhancement mechanism with a peak function in the non-canonical kinetic term in S-dual inflation. It is shown explicitly that the power spectrum for the primordial curvature perturbation can be enhanced at 10<sup>12</sup>, 10<sup>8</sup> and 10<sup>5</sup> Mpc<sup>–1</sup>, respectively, that the primordial black hole dark matter with peak mass around 10<sup>–13</sup> solar mass, the Earth’s mass and the stellar mass are generated, respectively, and that the scalar induced gravitational wave with peak frequency around mHz, μHz and nHz are created, respectively. The primordial black hole with the mass scale 10<sup>–13</sup> solar mass can make up almost all the dark matter and the associated scalar induced secondary gravitational waves is testable by spaced based gravitational wave observatory.</sec><sec>The amplitude of primordial curvature perturbations on a small scale can become large by the enhancement mechanism with a peak function in the non-canonical kinetic term. We apply the enhancement mechanism to S-dual inflation to produce abundant PBHs and observable scalar induced gravitational waves (SIGWs). The power spectrum on a large scale is consistent with observational constraint, and the power spectrum on a small scale is enhanced to the 0.01. It is possible that either sharp peak or broad peak possesses a different peak shape for the peak function by choosing a different value of <i>q</i>. By adjusting the peak position <i>ϕ</i><sub>p</sub> in the peak function, the power spectrum is enhanced on a different scale, henceforth associated with the generation of SIGWs with a different peak frequency, PBHs with different mass are produced. We choose three different values of <i>ϕ</i><sub>p</sub> to obtain enhance power spectrum at 10<sup>12</sup>, 10<sup>8</sup> and 10<sup>5</sup> Mpc<sup>–1</sup>, respectively. The enhanced curvature perturbation produces PBH DM with peak mass around 10<sup>–13</sup> solar mass, the Earth’s mass and the stellar mass, and SIGW with peak frequency around mHz, µHz and nHz, respectively. The stellar mass PBHs may explain black holes observed by LIGO/Virgo collaboration, and the earth-mass PBHs may explain the planet 9. The PBH with the mass scale 10<sup>–13</sup> solar mass can make up almost all the dark matter. The SIGW with the peak frequency around nHz is testable by pulsar timing array observations, and SIGW with the peak frequency around mHz is testable by space based GW observatory. The results show that the enhancement mechanism with a peak function in the non-canonical kinetic term works for S-dual inflation.</sec>

Research Again Origin of the Asymmetry Between Matter and Antimatter — Energy Basic State Field of the Universe (∐)

In this paper, we introduce the Dirac equation and the hole theory of antiparticle generation, and the history of antiparticle discover. We study of the physical properties of the antiparticles; we point out that antigravity does not exist. We introduce the ideas of two talented physicists and Cabibbo theory which have important influence on the research of origin of the matter–antimatter asymmetry, we propose that the “Dirac energy sea” is compatible with Feynman’s idea that antiparticles are “time reversals” of particles and be used to analyze some cosmological problems. In this paper, we review and analyze a lot of literatures about the asymmetry research on matter and antimatter generation, the available data from astronomical observations, and we can conclude that: everything around us within [Formula: see text] light-years is made of matter the present-day observable universe most likely does not contain significant amounts of antimatter. We provide extensive analysis and introduce observation of antimatter from space, review massive literature on related research, it shows that the present theory cannot give a reasonable explanation for this problem, the origin of matter–antimatter asymmetry remains unknown, although continuing advances in theory and improved experiment limits have ruled out some scenarios, for example, sphaleron-leptogenesis at the electroweak phase transition in the Standard Model and so on. Based on Huang’s theory of the creating of cosmic matter and my idea of the existence of energy basic state field (EBSF) in the universe, we point out the quantum turbulence generated by quantum super-fluidity in the initial period of the formation of the universe, a large number of high-energy solitons (matter) are formed after the Big Bang, it is called Huang-yang mechanism, which is different from the mechanism of antimatter creation and annihilation. In this paper, we also research that the production and annihilation of positive and negative matter promote to further evolving nuclear synthesis to form nucleons. It is absolutely not a perfect mirror symmetry between matter and antimatter when universe creations primordial matter.

Primordial black hole dark matter from inflation: The reverse engineering approach

Constraining the inflationary epoch is one of the aims of modern cosmology. In order to fully exploit current and future small-scale observations, it is necessary to devise tools to directly relate them to the early Universe's dynamics. We present here a novel reverse engineering approach able to connect fundamental late-time observables to consistent inflationary dynamics and, eventually, to the inflaton potential. Employing this procedure, we are able to describe which conditions can give rise to a raised plateau in the power spectrum of curvature perturbations at small scales, which are not constrained by CMB observations. Within this new phenomenologically driven approach, we find that inflation can generate a raised plateau in the spectrum of curvature perturbations that potentially connects three fundamental observables; a dominant component of the dark matter in the form of asteroid-mass/atomic-size primordial black holes, detectable signals in stochastic gravitational waves, and a subdominant fraction of stellar-mass primordial black holes mergers.

Search for primordial black hole dark matter with x-ray spectroscopic and imaging satellite experiments and prospects for future satellite missions

Ultra-light primordial black holes (PBHs) in the mass range of 10$^{16}$ - 10$^{22}$ g are allowed by current observations to constitute a significant fraction, if not all, of the dark matter in the Universe. In this work, we present limits on ultra-light, non-rotating PBHs which arise from the non-detection of the Hawking radiation signals from such objects in the keV-MeV energy band. Namely, we consider observations from the current-generation missions XMM-Newton and INTEGRAL/SPI and discuss the observational perspectives of the future missions Athena, eXTP, and THESEUS for PBH searches. Based on 3.4 Msec total exposure time XMM-Newton observations of Draco dwarf spheroidal galaxy, we conclude that PBH with masses $\lesssim 10^{16}$ g can not make all dark matter at 95% confidence level. Our ON-OFF-type analysis of $>100$ Msec of INTEGRAL/SPI data on the Milky Way halo puts significantly stronger constraints. Only $\lesssim 10$% dark matter can be presented by PBHs with masses $\lesssim 3\cdot 10^{16}$ g while the majority of dark matter can not be represented by PBHs lighter than $7\cdot 10^{16}$ g at 95% confidence level. We discuss the strong impact of systematic uncertainty related to the variations of instrumental and astrophysical INTEGRAL/SPI background on the derived results and estimate its level. We also show that future large-field-of-view missions such as THESEUS/X-GIS will be able to improve the constraints by a factor of 10-100 depending on the level of control under the systematics of these instruments.

Primordial black holes and gravitational waves from dissipation during inflation

We study the generation of a localized peak in the primordial spectrum of curvature perturbations from a transient dissipative phase during inflation, leading to a large population of primordial black holes. The enhancement of the power spectrum occurs due to stochastic thermal noise sourcing curvature fluctuations. We solve the stochastic system of Einstein equations for many realizations of the noise and obtain the distribution for the curvature power spectrum. We then propose a method to find its expectation value using a deterministic system of differential equations. In addition, we find a single stochastic equation whose analytic solution helps to understand the main features of the spectrum. Finally, we derive a complete expression and a numerical estimate for the energy density of the stochastic background of gravitational waves induced at second order in perturbation theory. This includes the gravitational waves induced during inflation, during the subsequent radiation epoch and their mixing. Our scenario provides a novel way of generating primordial black hole dark matter with a peaked mass distribution and a detectable stochastic background of gravitational waves from inflation.

Hunt for light primordial black hole dark matter with ultrahigh-frequency gravitational waves

Light primordial black holes may comprise a dominant fraction of the dark matter in our Universe. This paper critically assesses whether planned and future gravitational wave detectors in the ultra-high-frequency band could constrain the fraction of dark matter composed of sub-solar primordial black holes. Adopting the state-of-the-art description of primordial black hole merger rates, we compare various signals with currently operating and planned detectors. As already noted in the literature, our findings confirm that detecting individual primordial black hole mergers with currently existing and operating proposals remains difficult. Current proposals involving gravitational wave to electromagnetic wave conversion in a static magnetic field and microwave cavities feature a technology gap with respect to the loudest gravitational wave signals from primordial black holes of various orders of magnitude. However, we point out that one recent proposal involving resonant LC circuits represents the best option in terms of individual merger detection prospects in the range $(1\div 100) \, \text{MHz}$. In the same frequency range, we note that alternative setups involving resonant cavities, whose concept is currently under development, might represent a promising technology to detect individual merger events. We also show that a detection of the stochastic gravitational wave background produced by unresolved binaries is possible only if the theoretical sensitivity of the proposed Gaussian beam detector is achieved. Such a detector, whose feasibility is subject to various caveats, may be able to rule-out some scenarios for asteroidal mass primordial black hole dark matter. We conclude that pursuing dedicated studies and developments of gravitational wave detectors in the ultra-high-frequency band remains motivated and may lead to novel probes on the existence of light primordial black holes.

The State-of-art Analytical Models and Detectors for Black Holes

Since the 19th century, human beings have a much better understanding on the black holes with the fast progress on the optical detection technology. In this paper, the recent progress and the state-of-art detection scenarios for black holes are discussed, especially for the primordial black holes. With the result of evidence and theory, the current status of detecting black holes is detailly demonstrated. Specifically, five parts will be presented, the formation of the black holes, the growth of the black holes, the types of the black holes, the detection of the black holes and the relationship between primordial black holes and black matter. Overall, these results shed light on the astrophysics, the interaction between the black holes and the surrounding heavenly bodies and the universe with deeper insight.

Strong constraints on primordial black hole dark matter from 16 years of INTEGRAL/SPI observations

We present a new analysis of the diffuse soft $\gamma$-ray emission towards the inner Galaxy as measured by the SPectrometer aboard the INTEGRAL satellite (SPI) with 16 years of data taking. The analysis implements a spatial template fit of SPI data and an improved instrumental background model. We characterize the contribution of Primordial Black Holes (PBH) as dark matter (DM) candidates evaporating into $\mathcal{O}$(1) MeV photons by including, for the first time, the spatial distribution of their signal into the fitting procedure. No PBH signal is detected, and we set the strongest limit on PBH DM for masses up to $4 \times 10^{17}$ g, significantly closing in into the so-called asteroid mass range.

MYPHOENCYCLOPEDIC AND LINGUOPOETIC CHARACTERISTICS OF THE IMAGES OF "WATER" AND "FIRE" IN WORLD CULTURE

The article discusses the mythological, encyclopedic and linguo-poetic characteristics of the images of "water" and "fire" in different ethnic groups and societies. The image of "water" is an ancient universal symbol of all cultures of the world, as it is associated with the primordial matter and birth, as a result of which water is considered as the guardian of life, symbolizes its beginning and end. Fire is most often seen as a male substance and as a symbol of vital energy, the heart, the fertilizing force, enlightenment, the Sun. The image of "water" is not a holistic image, it consists of many forms: sea, river, ocean, lake, dew, stream, rain, downpour, thunderstorm, storm, ice, fog, well, spring. The image of "fire" is also objectified by different forms: a fireplace a candle, a flame, a bonfire. Much attention is paid to the description of the meanings of the main linguistic and mythopoetic characteristics of the images "water" and "fire" in the world, as well as in the Slavic mythopoetic picture of the world.

On the stability of the open-string QED neutron and dark matter

We study the stability of a hypothetical QED neutron, which consists of a color-singlet system of two $d$ quarks and a $u$ quark interacting with the QED interaction. As a quark cannot be isolated, the intrinsic motion of the three quarks in the lowest-energy state may lie predominantly in 1+1 dimensions, as in a $d$-$u$-$d$ open string. The attractive $d$-$u$ and $u$-$d$ QED interactions may overcome the weaker repulsive $d$-$d$ QED interaction to bind the three quarks together. We examine the QED neutron in a phenomenological three-body problem in 1+1 dimensions with an effective interaction extracted from Schwinger's exact QED solution in 1+1 dimensions. The phenomenological model in a variational calculation yields a stable QED neutron at 44.5 MeV. The analogous QED proton with two $u$ quarks and a $d$ quark has been found to be too repulsive to be stable and does not have a bound or continuum state, onto which the QED neutron can decay via the weak interaction. Consequently, the QED neutron is stable against the weak decay, has a long lifetime, and is in fact a QED dark neutron. It may be produced following the deconfinement-to-confinement phase transition of the quark gluon plasma in high-energy heavy-ion collisions. Because of the long lifetime of the QED dark neutron, self-gravitating assemblies of QED dark neutrons or dark antineutrons may be good candidates for a part of the primordial dark matter produced during the phase transition of the quark gluon plasma in the evolution of the early Universe.

Constraining primordial black hole dark matter with CHIME fast radio bursts

Strong lensing of fast radio bursts (FRBs) has been proposed as a relatively clean probe of primordial black hole (PBH) dark matter. Recently, the Canadian Hydrogen Intensity Mapping Experiment (CHIME) published a first catalog of 536 FRBs, 62 of which are from repeating sources. In light of this new data, we reexamine the prospects to constrain the abundance of PBHs via FRBs. Extending previous forecasts, we calculate a PBH dark matter bound using the intrinsic burst width and a calibrated flux-ratio threshold per FRB. In addition, we take into account the uncertainty in the relation between the FRB dispersion measure and source redshift. We outline an algorithm to detect lensed FRBs and a method to simulate its performance on real data and set a flux-ratio threshold for each event, which we use to infer realistic forecasts. We then attempt to extract a preliminary bound using the publicly available CHIME data. Unfortunately, both instrumental noise and the provided $\ensuremath{\sim}1\text{ }\text{ }\mathrm{ms}$ time-resolution of the public data hinder this effort. We identify one candidate event where a double burst could be explained via strong lensing by a $\mathcal{O}(10\text{ }\text{ }{M}_{\ensuremath{\bigodot}})$-mass PBH, which will require follow-up study at higher time resolution to either confirm or discard. We show that with a few times the size of the first catalog---sampled at the full instrumental time-resolution so that candidates can be efficiently scrutinized---CHIME will be able to find strong evidence for or robustly rule out PBHs with mass above $\ensuremath{\sim}10\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$ as the dark matter. Finally, we demonstrate that stacking repeating FRBs can improve the constraints, especially for lower masses.

The primordial matter power spectrum on sub-galactic scales

ABSTRACTThe primordial matter power spectrum quantifies fluctuations in the distribution of dark matter immediately following inflation. Over cosmic time, overdense regions of the primordial density field grow and collapse into dark matter haloes, whose abundance and density profiles retain memory of the initial conditions. By analysing the image magnifications in 11 strongly lensed and quadruply imaged quasars, we infer the abundance and concentrations of low-mass haloes, and cast the measurement in terms of the amplitude of the primordial matter power spectrum. We anchor the power spectrum on large scales, isolating the effect of small-scale deviations from the Lambda cold dark matter (ΛCDM) prediction. Assuming an analytic model for the power spectrum and accounting for several sources of potential systematic uncertainty, including three different models for the halo mass function, we obtain correlated inferences of $\log _{10}\left(P / P_{\Lambda \rm {CDM}}\right)$, the power spectrum amplitude relative to the predictions of the concordance cosmological model, of $0.0_{-0.4}^{+0.5}$, $0.1_{-0.6}^{+0.7}$, and $0.2_{-0.9}^{+1.0}$ at k = 10, 25, and 50 $\rm {Mpc^{-1}}$ at $68 {{\ \rm per\ cent}}$ confidence, consistent with CDM and single-field slow-roll inflation.

Primordial black hole dark matter in the presence of p-wave WIMP annihilation

We study the allowed primordial black hole (PBH) dark matter abundance in the mixed dark matter scenarios consisting of PBHs and self-annihilating weakly interacting massive particles (WIMPs) with a velocity dependent annihilation cross section. We first briefly illustrate how the WIMP dark matter halo profile changes for the velocity suppressed p-wave annihilation scenarios, compared with the familiar s-wave annihilation scenarios, and then discuss the PBH mass dependent upper bound on the allowed PBH dark matter abundance. The WIMPs can accrete onto a PBH to form an ultracompact minihalo with a spiky density profile. Such a spike is moderated in the central region of a halo because the WIMPs are annihilated away and this moderation is less effective for a smaller annihilation cross section. The WIMP core density becomes larger while the core radius becomes smaller for a velocity suppressed p-wave annihilation cross section than those for the s-wave annihilation scenarios. The annihilation cross section is dependent on the velocity which varies across the halo, and, in addition to the change of the WIMP density profile, another interesting feature is the PBH mass dependent bound on PBH dark matter abundance. This is in stark contrast to the s-wave annihilation scenarios where the PBH abundance bound is independent of the PBH mass. The allowed PBH dark matter fraction (with respect to the total dark matter abundance) is of order f PBH ≲ \U0001d4aa(10−7)(M⊙/MPBH)(−6+2γsp)/(3γsp+3) for the thermal relic p-wave dark matter with the mass 100 GeV where γsp is the slope index of the spike profile, to be compared with f PBH ≲ \U0001d4aa(10−9) for the corresponding thermal relic s-wave dark matter scenarios.

Mass classification of dark matter perturbers of stellar tidal streams

Stellar streams formed by tidal stripping of progenitors orbiting around the Milky Way are expected to be perturbed by encounters with dark matter subhalos. Recent studies have shown that they are an excellent proxy to infer properties of the perturbers, such as their mass. Here we present two different methodologies that make use of the fully non-Gaussian density distribution of stellar streams: a Bayesian model selection based on the probability density function (PDF) of stellar density, and a likelihood-free gradient boosting classifier. While the schemes do not assume a specific dark matter model, we are mainly interested in discerning the primordial black holes cold dark matter (PBH CDM) hypothesis form the standard particle dark matter one. Therefore, as an application we forecast model selection strength of evidence for cold dark matter clusters of masses 103–105M⊙ and 105–109M⊙, based on a GD-1-like stellar stream and including realistic observational errors. Evidence for the smaller mass range, so far under-explored, is particularly interesting for PBH CDM. We expect weak to strong evidence for model selection based on the PDF analysis, depending on the fiducial model. Instead, the gradient boosting model is a highly efficient classifier (99% accuracy) for all mass ranges here considered. As a further test of the robustness of the method, we reach similar conclusions when performing forecasts further dividing the largest mass range into 105–107M⊙ and 107–109M⊙ ranges.

Gravitational waves from dark matter isocurvature

The primordial fluctuations on large scales are adiabatic, but on smaller scales this need not be the case. Here we derive the general analytical framework to compute the stochastic gravitational wave background induced by primordial cold dark matter isocurvature fluctuations on small scales. We find that large isocurvature fluctuations can yield an observable gravitational wave signal, with a spectrum distinct from the one induced by adiabatic perturbations, and we provide for the first time the exact analytic expression of the kernel necessary to compute this signal. We then forecast the constraining power of future gravitational wave detectors on dark matter isocurvature on small scales and find they will dramatically improve on existing constraints.

Possible Early Universe Signals in Proton Collisions at the Large Hadron Collider

Our universe was born about 13.8 billion years ago from an extremely hot and dense singular point, in a process known as the Big Bang. The hot and dense matter which dominated the system within a few microseconds of its birth was in the form of a soup of elementary quarks and gluons, known as the quark-gluon plasma (QGP). Signatures compatible with the formation of the QGP matter have experimentally been observed in heavy-ion (such as Au or Pb) collisions at ultra-relativistic energies. Recently, experimental data of proton-proton (pp) collisions at the CERN Large Hadron Collider (LHC) have also shown signals resembling those of the QGP formation, which made these studies quite stimulating as to how the collision of small systems features in producing the early universe signals. In this article, we report on some of the compelling experimental results and give an account of the present understanding. We review the pp physics program at the LHC and discuss future prospects in the context of exploring the nature of the primordial matter in the early universe.

Signatures of primordial black hole dark matter at DUNE and THEIA

Primordial black holes (PBHs) are a potential dark matter candidate whose masses can span over many orders of magnitude. If their masses lie in the 1015 — 1017 g range, they can emit sizeable fluxes of MeV neutrinos through evaporation via Hawking radiation. We investigate the possibility of detecting light (non-)rotating PBHs with future neutrino experiments DUNE and THEIA. We show that these next-generation facilities will be able to set competitive constraints on PBH dark matter, providing complementary probes in a part of the PBH parameter space currently constrained mainly by photon data.