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Workshop on Very Light Dark Matter 2023

Mar 28 – 30, 2023
Mario Royal Kaikan (Chino, Nagano) + Online
Asia/Tokyo timezone

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Contribution List

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27. Dark Matter and Quantum Gravity
Toshifumi Noumi
3/28/23, 11:05 AM

Recent studies in the Swampland Program are pointing a possibility that quantum gravity constraints can be used to curve out the vast theory space of dark matters theoretically. In this talk, I will introduce our recent attempts to this direction based on unitarity of gravitational scattering amplitudes. In particular, I will discuss dark photon scenarios as an illustrative example and also...
14. Fuzzy Vector Dark Matter
Kaloian Lozanov
3/28/23, 11:45 AM

We will review the recent progress in the understanding of the non-relativistic weak-gravity dynamics of massive dark vector fields and whether they can play the role of dark matter in the late universe. We will also discuss different production mechanisms of vector dark matter in the primordial universe.
5. Production of very light dark photon dark matter
Naoya Kitajima
3/28/23, 12:05 PM

In this talk, I will show several production mechanisms of light dark photon dark matter in the early universe. It contains (i) resonant dark production from axion oscillation, (ii) dark photon emission form the collapse of cosmic string loops, (iii) misalignment production of coherently oscillating dark photons. Observational implications will also be discussed.
6. Stability of domain wall network with initial inflationary fluctuations, and its implications for cosmic birefringence
Diego Gonzalez
3/28/23, 12:25 PM

We study the formation and evolution of domain walls with initial inflationary fluctuations by numerical lattice calculations, correctly taking into account correlations on superhorizon scales. We find that, contrary to the widely-held claim, the domain wall network exhibits remarkable stability even when the initial distribution is largely biased toward one of the minima. This is due to the...
12. The evolution of domain wall network with inflationary fluctuations under the asymmetric potential
Junseok Lee
3/28/23, 2:00 PM

Domain wall networks can induce cosmological problems. Previous work has shown that networks with initial inflationary fluctuations are long-lived despite being under population bias. This is due to large scale correlations, which cannot be seen in white noise case. However, the fate of these networks under potential bias is not well-understood. In our research, we investigate the time...
11. Weak lensing and cosmic birefringence
Fumihiro Naokawa
3/28/23, 2:20 PM

Cosmic birefringence a newly reported signal from CMB and promising probe for new physics. In this talk, I am going to talk about weak lensing correction to Cosmic Birefringence signal. It will be important to use highly improved data by next generated CMB observations in the near future.
13. Cosmic birefringence tomography with late-time polarization signals
Toshiya Namikawa
3/28/23, 2:40 PM

In this presentation, I consider polarization signals after the reionization epoch to constrain rotation angles of CMB polarization plane for the cosmic birefringence tomography. The late-time polarization signals, the so-called polarized SZ (pSZ) effect, arises in the process of the scattering of the cosmic microwave background (CMB) photons off the electrons. The pSZ signals can be...
8. Probing Axions through Tomography of Anisotropic Cosmic Birefringence
Alessandro Greco
3/28/23, 3:20 PM

Cosmic birefringence is the in-vacuo rotation of the linear polarization plane experienced by photons of the Cosmic Microwave Background (CMB) radiation when theoretically well-motivated parity-violating extensions of Maxwell electromagnetism are considered. If the angle parametrizing such a rotation is dependent on the photon's direction, then this phenomenon is called Anisotropic Cosmic...
7. Search for vector dark matter in microwave cavities with Rydberg atoms
Jordan Gué
3/28/23, 3:40 PM

In this talk, I present a proposal of an experiment based on 1) the application of a strong electric field inside a microwave cavity and 2) electrometry using Rydberg atoms. This kind of experiment could be extremely useful at detecting dark photons through the stationary electric field filling the whole space it induces. The sensitivity of this experiment is quite constant over a significant...
29. Impact of HWP systematics on the measurement of cosmic birefringence from CMB polarization
Marta Monelli
3/28/23, 4:00 PM

Employing an half-wave plate (HWP) as polarization modulator is a promising strategy to mitigate systematics in CMB experiments. However, if not calibrated well enough or accounted for correctly in the analysis, its non-idealities represent an additional source of systematics that can impact the science extracted from CMB. In this talk, I will show how their effect on the observed angular...
28. How axions change stars
Konstantin Springmann
3/28/23, 5:00 PM

Lighter than expected QCD axions can get destabilized in sufficiently dense and large objects such as white dwarfs and neutron stars. Once the axion is sourced the mass of nucleons within the star is reduced, leading to a new ground state of nuclear matter. I will show that white dwarfs in this absolutely stable phase would look very different from what is observed, allowing us to set novel...
9. Probing ultra-light dark matter with lensed gravitational waves
Miguel Zumalacarregui
3/28/23, 5:40 PM

Probing cosmic structures with gravitational wave lensing Just like light, gravitational waves (GWs) are deflected and magnified by the large-scale structure of the Universe. Their low frequency, phase coherence and capacity to propagate with no absorption make GW lensing highly complementary to gravitational lensing of electromagnetic radiation. I will discuss the framework of lensing in the...
10. Motion of S2 and bounds on scalar clouds around SgrA*
Arianna Foschi
3/28/23, 6:00 PM

The motion of S2, one of the stars closest to the Galactic Centre, has been measured accurately and used to study the compact object at the centre of the Milky Way. It is commonly accepted that this object is a supermassive black hole but the nature of its environment is open to discussion. Here, we investigate the possibility that dark matter in the form of an ultralight scalar field “cloud”...
34. Information
Maresuke Shiraishi
3/28/23, 6:20 PM
26. Stochastic Properties of Ultralight Scalar Fields
Mariangela Lisanti
3/29/23, 9:00 AM

Ultralight axionlike particles are well-motivated dark matter candidates that are the target of numerous direct detection efforts. In the vicinity of the Solar System, such particles can be treated as oscillating scalar fields. The velocity dispersion of the Milky Way determines a coherence time of about
10
6
oscillations, beyond which the amplitude of the axion field fluctuates...
1. Gravitational impact of Supernovae in Ultra-light Axion Dark Matter halos
Victor H. Robles
3/29/23, 9:40 AM

One of the viable dark matter models is the Ultra-light Scalar field Dark Matter where it assumes an ultra-light axion-like particle of mass 10^(-22)eV. Current cosmological (dark matter only) simulations reveal that the dark matter halos formed in this model have a unique wave-like structure and a characteristic soliton at their centers. In this talk, I will discuss how these inners solitons...
3. Tidal Love numbers for environmental black-hole mergers
Valerio De Luca
3/29/23, 10:00 AM

Tidal Love numbers describe the deformability of compact objects under the presence of external tidal perturbations, and are found to be exactly zero for black holes. We discuss about the scenario of black holes dressed with an ultralight scalar field, addressing their detectability at future gravitational wave experiments.
2. The viability of ultralight bosonic dark matter in dwarf galaxies
Isabelle Goldstein
3/29/23, 11:10 AM

The dark matter distribution in dwarf galaxies holds a wealth of information on the fundamental properties and interactions of the dark matter particle. We study whether ultralight boson dark matter is consistent with the gravitational potential extracted from stellar kinematics. We use velocity dispersion measurements from six classical dwarf galaxies to show that axion-like particles with...
4. Continuous gravitational waves from self-interacting axion condensate
Hidetoshi Omiya
3/29/23, 11:30 AM

Ultra-light particles, such as axions, form a macroscopic condensate around a highly spinning black hole by the superradiant instability. The condensate emits characteristic gravitational waves, such as a monochromatic gravitational wave. The characteristic gravitational waves open the possibility of detecting the axion through gravitational wave search. However, the precise evolution of the...
16. Evolution of binary systems accompanying axion clouds in extreme mass ratio inspirals
Takuya Takahashi
3/29/23, 11:50 AM

Axions can form a cloud around a rotating black hole (BH) by the superradiant instability. We expect to be able to explore axions from gravitational waves (GWs) from binary BHs. In particular, when the BH with a cloud belongs to a binary system, the resonant phenomenon occurs during the inspiral phase. We study the evolution of binary systems accompanying the axion cloud around the resonance...
17. Quantum Nucleation of Chiral Soliton Lattice
Kohei Kamada
3/29/23, 12:10 PM

The Chiral Soliton Lattice (CSL) is a lattice structure composed of pion or axion domain walls aligned in parallel at equal intervals, which is energetically stable in the presence of a background magnetic field and a finite (baryon) chemical potential due to the topological term originated from the chiral anomaly. In this talk, I will discuss how to describe its formation by the quantum...
30. Axion Dark Matter from Frictional Misalignment
Alexandros Papageorgiou
3/29/23, 4:30 PM

We study the impact of sphaleron-induced thermal friction on the axion dark-matter abundance due to the interaction of an axion-like particle (ALP) with a dark non-abelian gauge sector in a secluded thermal bath. Thermal friction can either enhance the axion relic density by delaying the onset of oscillations or suppress it by damping them. We derive an analytical formula for the frictional...
22. Hybrid inflation driven by QCD axion
Yuma Narita
3/29/23, 5:10 PM

Inflation plays a central role in modern cosmology. In order to reheat the Universe, inflaton must couple to the Standard Model particles, including gluons. Meanwhile, the QCD axion may couple to gluons to solve the strong CP problem. In this study, we investigate the inflationary scenario involving a QCD axion and a scalar field coupled to gluons. We find that this scenario can solve the...
31. Multi-prong searches for light dark matter
Nancy Aggarwal
3/30/23, 9:00 AM
20. Bounds on Long-lived Dark Matter Mediators from Neutron Stars
Thong Nguyen
3/30/23, 9:40 AM

Neutron stars close to the Galactic center are expected to swim in a dense background of dark matter. For models in which the dark matter has efficient interactions with neutrons, they are expected to accumulate their own local cloud of dark matter, making them appealing targets for observations seeking signs of dark matter annihilation. For theories with very light mediators, the dark matter...
21. Sub-GeV dark matter search at ILC beam dumps
Daiki Ueda
3/30/23, 10:00 AM

Light dark matter particles may be produced in electron and positron beam dumps of the International Linear Collider (ILC). We propose an experimental setup to search for such events, the Beam-Dump eXperiment at the ILC (ILC-BDX). The setup consists of a muon shield placed behind the beam dump, followed by a multi- layer tracker and an electromagnetic calorimeter. The calorimeter can detect...
32. First Results of DANCE from Long-Term Observation
Yuka Oshima
3/30/23, 10:50 AM

Axions are one of the well-motivated candidates for dark matter, originally proposed to solve the strong CP problem in particle physics. Dark matter Axion search with riNg Cavity Experiment (DANCE) is a new experimental project to search for axion dark matter. We aim to detect the rotation and oscillation of optical linear polarization caused by axion-photon coupling with a bow-tie cavity....
33. Recent Upgrades of Optical System and Data Analysis in DANCE
Hiroki Fujimoto
3/30/23, 11:10 AM
24. Light dark matter around eV mass range
Wen Yin
3/30/23, 11:30 AM

I will talk about dark matter in eV mass range such as the experimental hints, future reaches, and dark matter theory.
18. Complementarity Probes of light dark sector via Gravitational Waves and Laboratories
Anish Ghoshal

The non-thermal production of dark matter (DM) usually requires very tiny couplings of the dark sector with the visible sector and therefore is notoriously challenging to hunt in laboratory experiments. Here we propose a novel pathway to test such a production in the context of a non-standard cosmological history, using both gravitational wave (GW) and laboratory searches. We investigate the...
25. contributed talk
19. Cosmic evolution and thermal stability of Barrow holographic dark energy in a nonflat Friedmann-Robertson-Walker Universe
Gaetano Luciano

We study the cosmological evolution of a nonflat Friedmann-Robertson-Walker Universe filled by pressureless dark matter and Barrow holographic dark energy (BHDE). The latter is a dark energy model based on the holographic principle with Barrow entropy instead of the standard Bekenstein-Hawking one. By assuming the apparent horizon of the Universe as IR cutoff, we explore both the cases where a...
15. Dark photon superradiance
Nils Siemonsen

I will describe the electrodynamics of a kinetically mixed dark photon cloud that forms through superradiance around a spinning black hole, and outline strategies to search for the resulting multi-messenger signals. A dark photon superradiance cloud sources a rotating dark electromagnetic field which, through kinetic mixing, induces a rotating visible electromagnetic field. Standard model...
23. Probing Virtual ALPs Using Precision Phase Measurement
Mohammad Sharifian

We propose an experimental scheme for detecting the effects of off-shell axion-like particles (ALPs) through optical cavities. In this proposed experiment, linearly polarized photons are pumped into an optical cavity where an external time-periodic or space-periodic magnetic field is present. The magnetic field mediates an interaction between the cavity photons and ALPs giving rise to a...
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