Conveners
Poster Lightning Talks: I
- Gulden Othman (University of Hamburg)
Poster Lightning Talks: II
- Hendrik Bekker (HIM)
Poster Lightning Talks: III
- Derek Jackson Kimball (California State University, East Bay)
Poster Lightning Talks: IV
- Kristof Schmieden (JGU Mainz)
A detection of cosmic birefringence (rotation of linear polarization) has the potential to revolutionize our understanding of fundamental physics and cosmology. Several recent analyses of Planck 2018 and WMAP data have reported tentative evidence, at ~3$\sigma$ significance, of a cosmic microwave background (CMB) birefringence signal which appears isotropic, static and achromatic.
Dark...
Single-photon atom gradiometry is a powerful experimental technique that can be employed to search for the oscillation of atomic transition energies induced by ultralight scalar dark matter (ULDM). Previous studies have focused on the sensitivity reach of these experiments down to ULDM masses of $\sim 10^{-16}$~eV, which would induce a signal oscillating at $\sim 10^{-1}$~Hz, where gravity...
Pulsar magnetospheres admit non-stationary vacuum gaps that are characterized by non-vanishing $\bf{E} \cdot \bf{B}$. These gaps play an important role in plasma production and electromagnetic wave emission and, as I will discuss, are very efficient axion factories. The density of gap-produced axions in the vicinity of the pulsar can exceed the local dark matter density by many orders of...
In this talk, I will propose the use of the Earth as a transducer for ultralight dark-matter detection. In particular I will point out a novel signal of both kinetically mixed dark-photon dark matter and axionlike dark matter: a monochromatic oscillating magnetic field generated at the surface of the Earth. Similar to the signal in a laboratory experiment in a shielded box (or cavity), this...
A dark matter overdensity around a black hole may significantly alter the dynamics of the black hole’s merger with another compact object. The strong gravitational potential of a black hole is theorised to lead to a significant increase in the concentration of dark matter in the central region with the creation of a “spike” in the dark matter density. We consider the case of OJ 287, which is...
We analyze the dynamics of cosmological perturbations in models of dark matter based on ultralight coherent bosons. We discuss two different regimes in evolution, which distinguish between a particle-like behavior and a wave-like behavior. For different spins of this bosonic dark matter, the background evolution can contain non-vanishing vector and tensor modes. The evolution of scalar, vector...
UPLOAD is an axion detection experiment which is a variation upon the haloscope detector, using two resonant microwave modes within a cavity and removing the need of an external magnetic field. The effect of an external magnetic field is substituted by the overlap between the electric and magnetic field components of the two resonating modes themselves. As implied in the name, coupling between...
The millimeter-wave photons are a crucial tool to address axion-like particles in the meV mass range, which is motivated in the post-inflationary scenario of axion. This mass range is the least constrained in the dark photon search as well. In dark matter halo WISPs search, it was reported that single photon sensors overwhelm the sensitivity of quantum-limited coherent detectors if the photon...
The axion is one of the most compelling dark matter (DM) candidates and a solution to the strong charge-parity problem. The DMRadio program consists of three experiments that together search for axions in the range 5 kHz - 200 MHz (20 peV - 0.8 $\mu$eV) with sensitivity to the DFSZ axion model: DMRadio-50L, DMRadio-m$^3$, and DMRadio-GUT. DMRadio-50L is a resonant lumped-element detector with...
A photon-magnon hybrid system naturally interacts with Dark Matter axions via the axion-electron coupling, and can therefore be used as an haloscope. We introduce a scheme where the axion field is detected through sidebands induced on a micorowave tone on resonance with cavity-magnon polaritons. The signal is proportional to the system quality factors and to the tone power, but, remarkably,...
The Ly-alpha forest traces the cosmic structure formation on smaller scales than complementary probes such as 21cm intensity mapping or CMB measurements. It is therefore well suited to study modern theories of fuzzy dark matter. However, the extraction of small scale structure information from the Ly-alpha forest poses some challenges as some of the observables become degenerate with the...
Axions and axion-like particles are hypothetical particles predicted in extensions of the standard model and are promising cold dark matter candidates. The Any Light Particle Search (ALPS II) experiment is a light-shining-through-the-wall experiment that aims to produce these particles from a strong light source and magnetic field and subsequently detect them through a reconversion into...
When seeking to understand symmetries of charge, parity, and time (the integral of phase), working in the easily visualized geometric representation of Clifford algebra rather than unintuitive matrix representations of Pauli and Dirac confers a remarkably clear and powerful perspective. Minimally complete vacuum wavefunction is the eight-component 3D Pauli algebra - 1 scalar, 3 vectors, 3...
Light scalar fields, such as axion-like particles (ALP), are promising dark matter candidates as they can be produced from the vacuum misalignment mechanism. In this work we investigate the mechanism in a less conventional regime where the ALP is subject to large fluctuations during its early dynamics. Our analysis is applied to the mechanism of cosmological relaxation of the electroweak...
The vanilla Lambda cold dark matter (ΛCDM) model has been so successful that 2018 constraints from the Planck collaboration are based on the variation of the same 6 cosmological parameters as the analysis of the BOOMERanG 1998 data. Yet, the lack of evidence for any constituent particle and various small-scale challenges of the vanilla Lambda cold dark matter (ΛCDM) have generated considerable...
We construct an effective theory (EFT) of an axion-like particle (ALP) for an additionally gauged $U(1)$ symmetry. The Z' is associated to a global current of the Standard Model (SM), such as baryon number ($B$) or baryon minus lepton number ($B-L$). In order to fulfill anomaly conditions as well as a trace condition, new fermions have to be introduced. Integrating out these fermions induces a...
CASPEr-Gradient searches for axion-like particles (ALP) which are a po-
tential dark matter candidate [1]. The gradient of the ALP field is predicted
to resemble a magnetic field in its coupling to nuclear spins [2]. Therefore, a
nuclear magnetic resonance (NMR) experiment is adopted to measure such a
gradient.
The NMR detection system has been commissioned for this research....
An overview of hyperpolarized Xe transport and sample preparation as part of our experimental program to search for QCD axions and axion-like particles (ALPs) as possible candidates for DM using NMR techniques within the cosmic axion spin precession experiment (CASPEr) is presented [1]. The NMR signals from these particles will be very weak so all possibilities for signal enhancement need to...
High quality factor bulk acoustic wave resonators provide a highly sensitive probe for fundamental physics research, as well as industry timing applications. When applied using the techniques and cryogenic technologies developed in the field of precision frequency metrology, these resonators can be used to place constraints on many emerging physical theories and even potentially detect new...
Heavy axion-like particles (ALPs), with masses up to a few 100 keV and coupled with photons can be efficiently produced in stellar plasmas, contributing to a significant energy-loss. This argument has been applied to helium burning stars in Globular Clusters (GCs) to obtain stringent bounds on the ALP-photon coupling g_aγ. However, for sufficiently large values of the ALP mass and coupling to...
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We investigate the impact of recent anomalous $(g-2)_{\mu}$ measurement with $\sim 4 \sigma$ deviation from the SM, probing its effect on a light GeV scale fermionic dark matter (DM). The $(g-2)_{\mu}$ anomaly can be readily explained in the a beyond the SM (BSM) $U(1)_{L_{\mu}-L_{\tau}}$ scenario, where only a portion of hitherto allowed parameter space can explain the anomaly. This...
The nature of dark matter, one of the major components of the cosmic standard model, remains one of the outstanding problems in physics. One interesting model is scalar field dark matter (SFDM), which fits naturally into observations in both particle physics and cosmology. Simulations and calculations using SFDM often use a classical field approximation (MFT) of the underlying quantum field...
Bose stars are gravitationally bound Bose-Einstein-Condensates in which the kinetic quantum pressure is stabilized by the self-gravitation and self-interaction of the scalar field.
In recent years, several interactions between these Condensates and astrophysical objects have been proposed: Bose star merger events could lead to supercritical soliton states, which can either shed a large...
So far, there is no experimental evidence of dark matter interacting with electromagnetism. Naively, this rules out any sizeable electric charge assigned to dark matter particles, thereby suppressing interactions with photons. Consequently, it is often taken for granted that a light dark matter candidate carrying a tiny electric charge is cosmologically stable. In this talk, I will argue that...
Nonlinear electrodynamic effects in vacuum have been predicted since the early days of Quantum Electrodynamics (QED) with the formulation of the Euler effective Lagrangian in 1935. Vacuum magnetic birefringence is one of these effects. Although experimental efforts have been active for more than 40 years, a direct laboratory observation of vacuum magnetic birefringence is still lacking as the...
We report on ongoing experimental searches for fundamental constant (FC) oscillations which are motivated within models of ultralight scalar dark matter (DM). In one search, the frequency of a bulk acoustic-wave quartz oscillator is compared to the frequency of the ${}^{87}$Rb ground-state hyperfine transition [1], to look for oscillations of the electron mass $m_e$, fine structure constant...
In this talk, we discuss recent computational advances in generating axion systems directly from Type IIb string geometries, including full axion spectra and vacua statistics, and show different methods in which these can put constraints on the landscape of possible compactifications, e.g. black hole superradiance.
The CERN Axion Solar Telescope (CAST) was a solar axion helioscope,
which produced the most stringent limits on multiple different
axion like particle candidate couplings by utilizing the inverse Primakoff
effect to convert particles into X-rays in a transverse magnetic field.
A gaseous detector based on 7 GridPixes, a combination of a $256 \times 256$ pixel Timepix ASIC and an...
Standard axion search methods rely on resonant cavities with a strong magnetic field.
These cavities must be tuneable in discrete steps to search for axions with small linewidths.
In this talk we will discuss a different method for searching for axions based on broadband
search ideas. Specifically we will focus on the Axion Quark Nugget (AQN) model. The
AQN model is based on earlier quark...
In recent years, optically-pumped magnetometers (OPMs) have been successfully used for setting new constraints on possible parameters of transient exotic spin couplings of axion dark matter. This was achieved with the help of the Global Network of Optical Magnetometers for Exotic physics searches (GNOME), being a world-wide network of synchronized magnetometers located in Europe, Asia,...
We investigate the effect of quantum loops on the theory of axionlike particles (ALPs) coupled to electrons. Contrary to some statements in the recent literature, the effective ALP-photon coupling induced by an electron loop can be sizeable in the plasma of a supernova. We define a general effective coupling that depends on the kinematics of the specific process in which an ALP scatters,...
We present a solution of the Schrodinger–Poisson system based on the WKB
ansatz for the wave function. In this way we obtain a description of a gravitationally bound
clump of axion dark matter by a superposition of energy eigenstates with random phases. It
can be applied to any self-consistent pair of radial density distribution and phase space den-
sity f (E) related by Eddington’s...
We provide bounds on the effective axion-like particle (ALP) to two-photon coupling obtained from the MUSE spectroscopic observations of six dwarf spheroidal galaxies between 470 and 935 nm. We search for the signal from radiative decays of ALPs under the assumption that they constitute the dark matter component of the haloes. These bounds are an update to those of arXiv:2009.01310 [astro-ph.CO].
In the scenario in which the axion is born after inflation, the field develops significant inhomogeneity and evolves in a highly nonlinear fashion. Understanding the eventual abundance and distribution of axionic dark matter in this scenario therefore requires dedicated numerical simulations. Here, we go beyond the QCD axion, and perform a suite of simulations for a range of possible...
Kinetic mixing between 𝑈(1) gauge groups is a well-known possible interaction between our visible Standard Model sector and a hidden sector supposed to contain dark matter. Naturally, the mixing coupling must be very small for the hidden sector to remain “almost” completely hidden. We aim to follow up on the established literature and investigate how very small kinetic mixing can arise in...
The Any Light Particle Search ALPS II is a light-shining-through-a-wall (LSW) experiment
to investigate the existence of axions and axion-like-particles (ALPs) in the sub-meV mass range. The existence of these particles is motivated by multiple quarters, from QCD to stellar physics. ALPS II aims to convert 1064 nm photons into axions or ALPs aided by the presence of a magnetic field, in an...
A complimentary scenario to superradiance is presented based on the possible existence of insta-
bilities in non-rotating black holes. A plausible parameter space for the formation of axion-type
scalar field clouds around black holes in cosmological times is determined, which allows establishing
bounds on the amount of dark matter as primordial black holes through axion-photon...
We show that a recent constraint on the cosmic birefringence effect due to dark energy can be related to the constraints on the coupling of axion dark matter to photon, by relying on a simple model of two-axion alignment mechanism with periodic potentials. Owing to the alignment of the potentials, one linear combination of two fields provides a nearly flat direction and acts as dark energy,...
The study of the density profile of dark matter (DM) on small scales provides valuable information about the mass distribution within the Galaxy and can predict new compact objects.
We take the sensitivity projections of future direct detection experiments to predict the observation times needed to detect small DM overdensities, assuming a DM cross section close to the current limit of...
Dilatons (and moduli) couple to the masses and coupling constants of ordinary matter, and these quantities are fixed by the local value of the dilaton field. If, in addition, the dilaton with mass mφ contributes to the cosmic dark matter density, then such quantities oscillate in time at the dilaton Compton frequency. We show how these oscillations lead to broadening and shifting of the Voigt...
Axion-like particles (ALPs), promising particle candidates of dark matter, can decay into photons through their electromagnetic couplings. However, thanks to their very large lifetime, they are extraordinarily stable. While exposed to ambient radiation of similar frequency as their mass, the decay rate of ALPs into photons is dramatically enhanced resulting in a detectable flux of photons, a...
We consider axions coupled to nucleons and photons only through the nucleon electric-dipole moment (EDM) portal. This coupling is a model-independent feature of QCD axions, which solve the strong CP problem, and might arise as well in more general axion-like particle setups. We revise the supernova (SN) axion emission induced by the nucleon EDM coupling and refine accordingly the SN 1987A...
We report a new experimental result on searching for exotic spin- and velocity- dependent force using a tungsten nucleon source and an K-Rb-21Ne comagnetometer [1]. The pseudomagnetic field from this exotic force is measured to be ≤ 7 aT. This sets new limits on coupling constants for the neutron-nucleon and proton-nucleon interactions in the force range of ≥ 0.1 m.
[1] Wei, Kai, et al....
In 2021 the Quantum Sensors for the Hidden Sector (QSHS) collaboration in the UK was founded and received funding to develop and demonstrate quantum devices with the potential to detect hidden sector particles primarily in the $\mu$eV to 100$\,\mu$eV mass window. The collaboration has been developing a range of devices and has started to develop a high-field, low-temperature facility at...
Axion haloscopes intend to detect axions from the galactic halo. In the absence of detection, they constrain axion parameters like mass and coupling strength. Doing so requires a precise estimate of the expected axion signal power. The expected signal power in turn depends on the axion-induced electromagnetic field which, without detection, cannot be measured. Experiments thus depend heavily...
Since the discovery of dark matter in our universe, numerous possible candidates have been proposed to explain its existence and composition. One of the candidates is the Ultralight axion-like particles, existing in the form of domain walls or axion stars, caused by topology or self-interactions. The Global Network of Optical Magnetometers to search for Exotic Physics (GNOME) looks for a...
