Field Dark Matter Research Articles

Towards a dark sector model from string theory

An embedding of a unified dark sector model into string theory with the following features is proposed: the model-independent axion descending from the Kalb-Ramond 2-form field is identified with the dark-matter field, and the real part of a Kähler modulus field — the “radius” of one of the extra spatial dimensions — accounts for dark energy. The expectation value of the dilaton field is stabilized by a gaugino condensation mechanism. A dark-energy potential with an amplitude corresponding to a realistic low energy scale results from some gentle tuning of the stabilized expectation value of the dilaton. The resulting potential reproduces the one in a previous dark-sector model proposed by two of us. Challenges to obtain a sufficiently flat potential are discussed.

Searching for axionlike time-dependent cosmic birefringence with data from SPT-3G

Ultralight axionlike particles (ALPs) are compelling dark matter candidates because of their potential to resolve small-scale discrepancies between $\Lambda$CDM predictions and cosmological observations. Axion-photon coupling induces a polarization rotation in linearly polarized photons traveling through an ALP field; thus, as the local ALP dark matter field oscillates in time, distant static polarized sources will appear to oscillate with a frequency proportional to the ALP mass. We use observations of the cosmic microwave background from SPT-3G, the current receiver on the South Pole Telescope, to set upper limits on the value of the axion-photon coupling constant $g_{\phi\gamma}$ over the approximate mass range $10^{-22} - 10^{-19}$ eV, corresponding to oscillation periods from 12 hours to 100 days. For periods between 1 and 100 days ($4.7 \times 10^{-22} \text{ eV} \leq m_\phi \leq 4.7 \times 10^{-20} \text{ eV}$), where the limit is approximately constant, we set a median 95% C.L. upper limit on the amplitude of on-sky polarization rotation of 0.071 deg. Assuming that dark matter comprises a single ALP species with a local dark matter density of $0.3\text{ GeV/cm}^3$, this corresponds to $g_{\phi\gamma} < 1.18 \times 10^{-12}\text{ GeV}^{-1} \times \left( \frac{m_{\phi}}{1.0 \times 10^{-21} \text{ eV}} \right)$. These new limits represent an improvement over the previous strongest limits set using the same effect by a factor of ~3.8.

Galaxy and halo angular clustering in ΛCDM and modified gravity cosmologies

Using a suite of $N$-body simulations, we study the angular clustering of galaxies, halos, and dark matter in $\mathrm{\ensuremath{\Lambda}}$ cold dark matter and modified gravity (MG) scenarios. We consider two general categories of such MG models, one is the $f(R)$ gravity, and the other is the normal branch of the Dvali-Gabadadze-Porrati brane world. To measure angular clustering we construct a set of observer-frame light cones and resulting mock sky catalogs. We focus on the area-averaged angular correlation functions ${W}_{J}$, and the associated reduced cumulants ${S}_{J}\ensuremath{\equiv}{W}_{J}/{W}_{2}^{(J\ensuremath{-}1)}$, and robustly measure them up to the ninth order using counts in cells. We find that $0.15&lt;z&lt;0.3$ is the optimal redshift range to maximize the MG signal in our light cones. Analyzing various scales for the two types of statistics, we identify up to 20% relative departures in MG measurements from general relativity (GR), with varying signal significance. For the case of halos and galaxies, we find that third-order statistics offer the most sensitive probe of the different structure formation scenarios, with both ${W}_{3}$ and the reduced skewness ${S}_{3}$ reaching from $2\ensuremath{\sigma}$ to $4\ensuremath{\sigma}$ significance at angular scales $\ensuremath{\theta}\ensuremath{\sim}0.13\ifmmode^\circ\else\textdegree\fi{}$. The MG clustering of the smooth dark matter field is characterized by even stronger deviations ($\ensuremath{\gtrsim}5\ensuremath{\sigma}$) from GR, albeit at a bit smaller scales of $\ensuremath{\theta}\ensuremath{\sim}0.08\ifmmode^\circ\else\textdegree\fi{}$, where baryonic physics is already important. Finally, we stress that our mock halo and galaxy catalogs are characterized by rather low surface number densities when compared to existing and forthcoming state-of-the-art photometric surveys. This opens up exciting potential for testing GR and MG using angular clustering in future applications, with even higher precision and significance than reported here.

Distinguishing Dirac vs. Majorana neutrinos: a cosmological probe

Cosmic background neutrinos (CνB) helicity composition is different for Dirac or Majorana neutrinos making detectors based on CνB capture sensitive to the nature of neutrinos. We calculate, for the first time, the helicity changes of neutrinos crossing dark matter fields, to quantitatively calculate this effect on the capture rate. We show that a fraction of neutrinos change their helicity, regardless of them being deflected by a void or a dark matter halo. The average signal from the 100 most massive voids or halos in a Gpc3 gives a prediction that if neutrinos are Dirac, the density of the CνB background measured on Earth should be 48 cm-3 for left-helical neutrinos, a decrease of 15% (53.6 cm-3; 5%) for a halo (void) with respect to the standard calculation without including gravitational effects due to large scale structures. In terms of the total capture rate in a 100 g tritium detector, this translates in 4.9+1.1 -0.8 neutrinos per year for the Dirac case, as a function of the unknown neutrino mass scale, or 8.1 per year if neutrinos are Majorana. Thus although smaller than the factor two for the non-relativistic case, it is still large enough to be detected and it highlights the power of future CνB detectors, as an alternative to neutrinoless double beta decay experiments, to discover the neutrino nature.

Simultaneous Dependence of Matter Clustering on Scale and Environment

In this work, we propose new statistical tools that are capable of characterizing the simultaneous dependence of dark matter and gas clustering on the scale and the density environment, and these are the environment-dependent wavelet power spectrum (env-WPS), the environment-dependent bias function (env-bias), and the environment-dependent wavelet cross-correlation function (env-WCC). These statistics are applied to the dark matter and baryonic gas density fields of the TNG100-1 simulation at redshifts of z=3.0-0.0, and to Illustris-1 and SIMBA at z = 0. The measurements of the env-WPSs suggest that the clustering strengths of both the dark matter and the gas increase with increasing density, while that of a Gaussian field shows no density dependence. By measuring the env-bias and env-WCC, we find that they vary significantly with the environment, scale, and redshift. A noteworthy feature is that at z = 0.0, the gas is less biased in denser environments of Δ ≳ 10 around 3 h Mpc−1, due to the gas reaccretion caused by the decreased AGN feedback strength at lower redshifts. We also find that the gas correlates more tightly with the dark matter in both the most dense and underdense environments than in other environments at all epochs. Even at z = 0, the env-WCC is greater than 0.9 in Δ ≳ 200 and Δ ≲ 0.1 at scales of k ≲ 10 h Mpc−1. In summary, our results support the local density environment having a non-negligible impact on the deviations between dark matter and gas distributions up to large scales.

Search for Dark-Matter-Induced Oscillations of Fundamental Constants Using Molecular Spectroscopy.

A possible implication of an ultralight dark matter field interacting with the standard model degrees of freedom is oscillations of fundamental constants. Here, we establish direct experimental bounds on the coupling of an oscillating ultralight dark matter field to the up, down, and strange quarks and to the gluons, for oscillation frequencies between 10 and 10^{8} Hz. We employ spectroscopic experiments that take advantage of the dependence of molecular transition frequencies on the nuclear masses. Our results apply to previously unexplored frequency bands and improve on existing bounds at frequencies >5 MHz. We also improve on the bounds for coupling to the electromagnetic field and the electron field, in particular spectral windows. We identify a sector of ultralight dark matter and standard model coupling space where thebounds from equivalence principle tests may be challenged by next-generation experiments of the present kind.

Motion of charged and spinning particles influenced by dark matter field surrounding a charged dyonic black hole

We investigate the motion of massive charged and spinning test particles around a charged dyonic black hole spacetime surrounded by perfect fluid scalar dark matter field. We obtain the equations of motion and find the expressions for the four-velocity for the case of a charged particle, and four-momentum components for the case of a spinning particle. The trajectories for various values of electric $Q_{e}$ and magnetic $Q_{m}$ charges are investigated under the influence of dark matter field $\lambda$. We find the equations of motion of a spinning particle that follows a non-geodesic trajectory via Lagrangian approach in addition to the charged and non-spinning particles that follow geodesic motion in this set-up. We study in detail the properties of innermost stable circular orbits (ISCOs) in the equatorial plane. The study of ISCOs of a spinning massive particle is done by using the pole-dipole approximation. We show that, in addition to the particle's spin, the dark matter field parameter $\lambda$ and black hole charges ($Q_{m}\;\text{and}\;Q_{e}$) have a significant influence on the ISCOs of spinning particles. It is observed that if the spin is parallel to the total angular momentum $J$ (i.e. $\mathcal{S}>0$), the ISCO parameters (i.e.$r_{ISCO}, L_{ISCO}\;\text{and}\; E_{ISCO}$) of a spinning particle are smaller than those of a non-spinning particle, whereas if the spin is anti-parallel to total angular momentum $J$ (i.e. $\mathcal{S}<0$), the value of the ISCO parameters is greater than that of the non-spinning particle. We also show that for the corresponding values of spin parameter S, the behaviour of Keplerian angular frequency of ISCO $\Omega_{ISCO}$ is opposite to that of $r_{ISCO}, L_{ISCO}\; \text{and}\; E_{ISCO}$.

Effects of variation of the fine structure constant α and quark mass mq in Mössbauer nuclear transitions

High accuracy measurements in M\"ossbauer transitions open up the possibility to use them in the search for temporal and spatial variations of the fine structure constant $\ensuremath{\alpha}$, quark mass ${m}_{q}$, and dark matter field which may lead to the variations of $\ensuremath{\alpha}$ and ${m}_{q}$. We calculate the sensitivity of nuclear transitions to variations of $\ensuremath{\alpha}$ and ${m}_{q}$. M\"ossbauer transitions have high sensitivity to variation of quark mass ${m}_{q}$ and the strong interaction scale ${\mathrm{\ensuremath{\Lambda}}}_{\mathrm{QCD}}$ to which atomic optical clocks are not sensitive. The enhancement factors $K$, defined by $\frac{\ensuremath{\delta}f}{f}={K}_{\ensuremath{\alpha}}\frac{\ensuremath{\delta}\ensuremath{\alpha}}{\ensuremath{\alpha}}$ and $\frac{\ensuremath{\delta}f}{f}={K}_{q}\frac{\ensuremath{\delta}{m}_{q}}{{m}_{q}}$ where $f$ is the transition energy, may be large in some transitions. The 8-eV nuclear clock transition in $^{229}\mathrm{Th}$ $({K}_{q}\ensuremath{\approx}{10}^{4})$ and 76-eV transition in $^{235}\mathrm{U}$ $({K}_{\ensuremath{\alpha}}\ensuremath{\approx}{K}_{q}\ensuremath{\approx}{10}^{3})$ may be investigated using laser spectroscopy methods.

Neutrino meets ultralight dark matter: 0νββ decay and cosmology

We explore the neutrinoless double beta (0νββ) decay induced by an ultralight dark matter field coupled to neutrinos. The effect on 0νββ decay is significant if the coupling violates the lepton number, for which the ΔL = 2 transition is directly driven by the dark matter field without further suppression of small neutrino masses. As the ultralight dark matter can be well described by a classical field, the effect features a periodic modulation pattern in decay events. However, we find that in the early Universe such coupling will be very likely to alter the standard cosmological results. In particular, the requirement of neutrino free-streaming before the matter-radiation equality severely constrains the parameter space, such that the future 0νββ decay experiments can hardly see any signal even with a meV sensitivity to the effective neutrino mass.

The cosmic web connection to the dark matter halo distribution through gravity

ABSTRACT This work investigates the connection between the cosmic web and the halo distribution through the gravitational potential at the field level. We combine three fields of research, cosmic web classification, perturbation theory expansions of the halo bias, and halo (galaxy) mock catalogue making methods. In particular, we use the invariants of the tidal field and the velocity shear tensor as generating functions to reproduce the halo number counts of a reference catalogue from full gravity calculations, populating the dark matter field on a mesh well into the non-linear regime ($3\, h^{-1}\, {\rm Mpc}$ scales). Our results show an unprecedented agreement with the reference power spectrum within 1 per cent up to $k=0.72\, h\, {\rm Mpc}^{-1}$. By analysing the three-point statistics on large scales (configurations of up to $k=0.2\, h\, {\rm Mpc}^{-1}$), we find evidence for non-local bias at the 4.8σ confidence level, being compatible with the reference catalogue. In particular, we find that a detailed description of tidal anisotropic clustering on large scales is crucial to achieve this accuracy at the field level. These findings can be particularly important for the analysis of the next generation of galaxy surveys in mock galaxy production.

New constraints on axion-like dark matter using a Floquet quantum detector.

Dark matter is one of the greatest mysteries in physics. It interacts via gravity and composes most of our universe, but its elementary composition is unknown. We search for nongravitational interactions of axion-like dark matter with atomic spins using a precision quantum detector. The detector is composed of spin-polarized xenon gas that can coherently interact with a background dark matter field as it traverses through the galactic dark matter halo. Conducting a 5-month-long search, we report on the first results of the Noble and Alkali Spin Detectors for Ultralight Coherent darK matter (NASDUCK) collaboration. We limit ALP-neutron interactions in the mass range of 4 × 10−15 to 4 × 10−12 eV/c2 and improve upon previous terrestrial bounds by up to 1000-fold for masses above 4 × 10−13 eV/c2. We also set bounds on pseudoscalar dark matter models with quadratic coupling.

Dark Matter and Real-Particle Field Theory

Based on real-particle field theory, this research demonstrates that dark matter comprises elastic electrons with a full cosmic background. In the real-particle field theory, real particles are elastic particles with both mass and volume. Real particles have three independent motion modes and two symmetrical interactions. The evolution of the real-particle field follows a set of Poisson equations. The theory shows that the electric and magnetic potentials represent electronic interactions of mass attraction and motion repulsion. The electromagnetic and dark-matter fields are essentially elastic electron fields. The laws of mechanics, gravitation, and electromagnetism of classical physics can be inferred from the real-particle field theory. In the electron field, electronic clusters are photons with the energy proportional to vibration frequency. The mechanic features of photons can be characterized by their volume, mass, and elasticity. Furthermore, the radiation of electronic clusters follows Planck’s law, which indicates that dark matter has a uniform density and no photonic current in the cosmic background. It is shown that matter essentially comprises discrete particles, and the matter field is merely a statistical convolution effect of a large number of particles. Consequently, dark matter particles contribute to the structural formation of all matter in the universe.

Effect of perfect fluid dark matter on particle motion around a static black hole immersed in an external magnetic field

We investigate particle and photon motion in the vicinity of a static and spherically symmetric black hole surrounded by perfect fluid dark matter in the presence of an external asymptotically uniform magnetic field. We determine the radius of the innermost stable circular orbit (ISCO) for charged test particles and the radius for unstable circular photon orbits and show that the effect of the presence of dark matter shrinks the values of ISCO and photon sphere radii. Based on the analysis of the ISCO radius we further show that the combined effects of dark matter and magnetic field can mimic the spin of a Kerr black hole up to a/M≈0.75−0.8. Finally, we consider the effect of the presence of dark matter on the center of mass energy of colliding particles in the black hole vicinity. We show that the center of mass energy grows as the value of the dark matter parameter increases. This result, in conjunction with the fact that, in the presence of an external magnetic field, the ISCO radius can become arbitrarily close to the horizon leads to arbitrarily high energy that can be extracted by the collision process, similarly to what is observed in the super-spinning Kerr case.

Stochastic fluctuations of bosonic dark matter

Numerous theories extending beyond the standard model of particle physics predict the existence of bosons that could constitute dark matter. In the standard halo model of galactic dark matter, the velocity distribution of the bosonic dark matter field defines a characteristic coherence time τc. Until recently, laboratory experiments searching for bosonic dark matter fields have been in the regime where the measurement time T significantly exceeds τc, so null results have been interpreted by assuming a bosonic field amplitude Φ0 fixed by the average local dark matter density. Here we show that experiments operating in the T ≪ τc regime do not sample the full distribution of bosonic dark matter field amplitudes and therefore it is incorrect to assume a fixed value of Φ0 when inferring constraints. Instead, in order to interpret laboratory measurements (even in the event of a discovery), it is necessary to account for the stochastic nature of such a virialized ultralight field. The constraints inferred from several previous null experiments searching for ultralight bosonic dark matter were overestimated by factors ranging from 3 to 10 depending on experimental details, model assumptions, and choice of inference framework.

Search for dark-photon dark matter in the SuperMAG geomagnetic field dataset

In our recent companion paper [arXiv:2106.00022], we pointed out a novel signature of ultralight kinetically mixed dark-photon dark matter. This signature is a quasi-monochromatic, time-oscillating terrestrial magnetic field that takes a particular pattern over the surface of the Earth. In this work, we present a search for this signal in existing, unshielded magnetometer data recorded by geographically dispersed, geomagnetic stations. The dataset comes from the SuperMAG Collaboration and consists of measurements taken with one-minute cadence since 1970, with $\mathcal{O}(500)$ stations contributing in all. We aggregate the magnetic field measurements from all stations by projecting them onto a small set of global vector spherical harmonics (VSH) that capture the expected vectorial pattern of the signal at each station. Within each dark-photon coherence time, we use a data-driven technique to estimate the broadband background noise in the data, and search for excess narrowband power in this set of VSH components; we stack the searches in distinct coherence times incoherently. Following a Bayesian analysis approach that allows us to account for the stochastic nature of the dark-photon dark-matter field, we set exclusion bounds on the kinetic mixing parameter in the dark-photon dark-matter mass range $2\times10^{-18}\,\text{eV} \lesssim m_{A'} \lesssim 7\times10^{-17}\,\text{eV}$ (corresponding to frequencies $6\times 10^{-4}\,\text{Hz}\lesssim f_{A'} \lesssim 2\times 10^{-2}\,\text{Hz}$). These limits are complementary to various existing astrophysical constraints. Although our main analysis also identifies a number of candidate signals in the SuperMAG dataset, these appear to either fail or be in tension with various additional robustness checks we apply to those candidates. We report no robust and significant evidence for a dark-photon dark-matter signal in the SuperMAG dataset.

Search for axion-like dark matter with spin-based amplifiers

Ultralight axion-like particles are well-motivated dark matter candidates introduced by theories beyond the standard model of particle physics. However, directly constraining their parameter space with laboratory experiments usually yields weaker limits than indirect approaches relying on astrophysical observations. Here we report the search for axion-like particles with a quantum sensor in the mass range of 8.3–744.0 feV. The sensor makes use of hyperpolarized long-lived nuclear spins as a pre-amplifier that effectively enhances a coherently oscillating axion-like dark matter field by a factor of more than 100. Using these spin-based amplifiers, we achieve an ultrahigh magnetic sensitivity of 18 fT Hz–(1/2), which exceeds the performance of state-of-the-art nuclear spin magnetometers. Our experiment constrains the parameter space describing the coupling of axion-like particles to nucleons over the aforementioned mass range, namely, at 67.5 feV reaching 2.9 × 10−9 GeV−1, improving on previous laboratory constraints by at least five orders of magnitude. Our measurements also constrain the quadratic interaction between axion-like particles and nucleons as well as interactions between dark photons and nucleons, exceeding bounds from astrophysical observations. A search for axion-like dark matter with a quantum sensor that enhances potential signals is reported. This work constrains the parameter space of different interactions between nucleons and axion-like particles and between nucleons and dark photons.

Ringing of a black hole in a dark matter halo

Recently, we obtained the simple metrics of a spherically symmetric black hole in a dark matter halo, and extended to the case of rotation. As the characteristic sound of black holes, quasinormal modes (QNMs) are one of the important means to understand black holes currently. Based on these two metrics of a spherically symmetric black hole, we study the QNMs of cold dark matter (CDM) and scalar field dark matter (SFDM) models using the methods of the material field perturbations and the gravitational perturbation, and make comparisons with the Schwarzschild black hole. Our results show that black hole QNMs of CDM and SFDM in a dark matter halo are different from the Schwarzschild black hole, unlike a Schwarzschild black hole with a prominent power-law tail. The different kinds models of dark matter can be distinguished by their QNMs. The time of QNMs ringing and frequencies increase with increasing parameter $l$. The overall QNMs of CDM are stronger than that of SFDM in the same condition, which is easier to be detected. In addition, QNMs frequencies using the sixth-order WKB method and the Prony method are in good agreement.

The Bias from Hydrodynamic Simulations: Mapping Baryon Physics onto Dark Matter Fields

Abstract This paper investigates the hierarchy of baryon physics assembly bias relations obtained from state-of-the-art hydrodynamic simulations with respect to the underlying cosmic web spanned by the dark matter field. Using the Bias Assignment Method we find that nonlocal bias plays a central role. We classify the cosmic web based on the invariants of the curvature tensor defined not only by the gravitational potential, but especially by the overdensity, as small-scale clustering becomes important in this context. First, the gas density bias relation can be directly mapped onto the dark matter density field to high precision exploiting the strong correlation between them. In a second step, the neutral hydrogen is mapped based on the dark matter and the gas density fields. Finally, the temperature is mapped based on the previous quantities. This permits us to statistically reconstruct the baryon properties within the same simulated volume finding percent precision in the two-point statistics and compatible results in the three-point statistics, in general within 1σ, with respect to the reference simulation (with 5–6 orders of magnitude less computing time). This paves the path to establish the best setup for the construction of mocks probing the intergalactic medium for the generation of such key ingredients in the statistical analysis of large forthcoming missions such as DESI, Euclid, J-PAS, and WEAVE.

Towards testing the theory of gravity with DESI: summary statistics, model predictions and future simulation requirements

Shortly after its discovery, General Relativity (GR) was applied to predict the behavior of our Universe on the largest scales, and later became the foundation of modern cosmology. Its validity has been verified on a range of scales and environments from the Solar system to merging black holes. However, experimental confirmations of GR on cosmological scales have so far lacked the accuracy one would hope for — its applications on those scales being largely based on extrapolation and its validity there sometimes questioned in the shadow of the discovery of the unexpected cosmic acceleration. Future astronomical instruments surveying the distribution and evolution of galaxies over substantial portions of the observable Universe, such as the Dark Energy Spectroscopic Instrument (DESI), will be able to measure the fingerprints of gravity and their statistical power will allow strong constraints on alternatives to GR.In this paper, based on a set of N-body simulations and mock galaxy catalogs, we study the predictions of a number of traditional and novelsummary statistics beyond linear redshift distortions in two well-studied modified gravity models — chameleon f(R) gravity and a braneworld model — and the potential of testing these deviations from GR using DESI. Thesesummary statistics employ a wide array of statistical properties of the galaxy and the underlying dark matter field, including two-point and higher-order statistics, environmental dependence, redshift space distortions and weak lensing. We find that they hold promising power for testing GR to unprecedented precision. The major future challenge is to make realistic, simulation-based mock galaxy catalogs for both GR and alternative models to fully exploit the statistic power of the DESI survey (by matching the volumes and galaxy number densities of the mocks to those in the real survey) and to better understand the impact of key systematic effects. Using these, we identify future simulation and analysis needs for gravity tests using DESI.

From EMBER to FIRE: predicting high resolution baryon fields from dark matter simulations with deep learning

ABSTRACT Hydrodynamic simulations provide a powerful, but computationally expensive, approach to study the interplay of dark matter and baryons in cosmological structure formation. Here, we introduce the EMulating Baryonic EnRichment (EMBER) Deep Learning framework to predict baryon fields based on dark matter-only simulations thereby reducing computational cost. EMBER comprises two network architectures, U-Net and Wasserstein Generative Adversarial Networks (WGANs), to predict 2D gas and H i densities from dark matter fields. We design the conditional WGANs as stochastic emulators, such that multiple target fields can be sampled from the same dark matter input. For training we combine cosmological volume and zoom-in hydrodynamical simulations from the Feedback in Realistic Environments (FIRE) project to represent a large range of scales. Our fiducial WGAN model reproduces the gas and H i power spectra within 10 per cent accuracy down to ∼10 kpc scales. Furthermore, we investigate the capability of EMBER to predict high resolution baryon fields from low resolution dark matter inputs through upsampling techniques. As a practical application, we use this methodology to emulate high-resolution H i maps for a dark matter simulation of a $L=100\, \text{Mpc}\, h^{ -1}$ comoving cosmological box. The gas content of dark matter haloes and the H i column density distributions predicted by EMBER agree well with results of large volume cosmological simulations and abundance matching models. Our method provides a computationally efficient, stochastic emulator for augmenting dark matter only simulations with physically consistent maps of baryon fields.