Recent studies reveal that more than a dozen of white dwarfs displaying near-perfect blackbody spectra in the optical range have been lurking in the Sloan Digital Sky Survey catalog. We point out that, in a way analogous to the cosmic microwave background, these stars serve as excellent test beds for new physics. Specifically, we show how their observed lack of spectral distortions translates...
We employ the effective field theory approach to analyze the characteristics of Euclidean wormholes within axion theories. Using this approach, we obtain non-perturbative instantons in various complex scalar models with and without a non-minimal coupling to gravity, as well as models featuring the R2 term for a range of coupling values. This yields a series of analytical expressions for the...
I would like to present a new experimental proposal, called LACME, to search for axion dark matter in the laboratory. If axions or axion-like particles are the main component of dark matter, they will modify the transport property of electrons and also the atomic spectra, which will give a new way of detecting axions or axion-like particles. Finally I will discuss a topological soliton made...
We propose new ideas to directly search for light axion dark matter by using magnetometry with nitrogen-vacancy centers in diamonds. If the axion dark matter couples to the electron spin, it affects the evolution of the Bloch vectors consisting of the spin-triplet states, which may be detected through several magnetometry techniques. We give several concrete examples with the use of dc and ac...
Zoom link: https://pusan.zoom.us/j/86275799785pwd=EK6wqm0UJV8aZDqvvpmaE3UMHXsbVo.1
(ID : 862 7579 9785, Code secret: 335557)
In this talk I will describe how one can use collective effects in materials to detect axion dark matter (DM). I will first discuss topological magnetic insulators which can host axion quasiparticles (AQs). The AQs can resonantly mix with DM axions and photons...
https://pusan.zoom.us/j/85641446219?pwd=KI4Z5tkyAIncbVsVV5npyDjbpqrXtb.1
(ID : 856 4144 6219, Code secret: 650333)
In the presence of radiation from bright astrophysical sources at radio frequencies, axion dark matter can undergo stimulated decay to two nearly back-to-back photons, meaning that bright sources could have faint counterimages in other parts of the sky. The counterimages will...
I will discuss a novel search for axions using spectropolarimetric observations of magnetic white dwarfs (MWDs). Photons produced as thermal radiation at the MWD surface may convert into an axion as they traverse the magnetosphere, but only the component polarized parallel to the MWD magnetic field. Therefore the MWD radiation at Earth is linearly polarized perpendicular to the magnetic field...
The study of localised stable solitons in 3+1 dimensional field theory often hinges on a loophole to Derrick's theorem that states that stable localised solutions may exist if they are periodic in time, such as in the case of a time dependent complex phase. The possible presence and influence of such dynamic solitons may have important consequences for the evolution of the early universe in...
https://pusan.zoom.us/j/86061341145?pwd=ofYF9LIMw9rfV54TCC9sbsr3Nle22M.1
(ID : 860 6134 1145, Code secret: 615519)
https://pusan.zoom.us/j/88351724378?pwd=p0nnAOQCvPQHYNHm0K3qpiIzs1kyJH.1
(ID : 883 5172 4378, Code secret: 744378)
We study axion-photon couplings in compactifications of type IIB string theory.
We find that these couplings are systematically suppressed compared to the inverse axion periodicity, as a result of two effects. First, couplings to the QED theta angle are suppressed for axion mass eigenstates that are light compared to the mass scale set by stringy instantons on the cycle supporting QED. ...
Non-invertible global symmetry often predicts degeneracy in axion potentials and carries important information about the global form of the gauge group. When these symmetries are spontaneously broken they can lead to the formation of stable axion domain wall networks which support topological degrees of freedom on their worldvolume. Such non-invertible symmetries can be broken by embedding...
We propose a minimal extension of the Standard Model with the Peccei-Quinn (PQ) scalar field and explain the relic density of the QCD axion through the kinetic misalignment with a relatively small axion decay constant. To this purpose, we consider a slow-roll inflation from the radial component of the PQ field with the PQ conserving potential near the pole of its kinetic term and investigate...
With the Belle II and Belle experiments, we have a cleanly defined e+e- initial state and a nearly hermetic detector of almost 4\pi solid-angle coverage. This is a great advantage for studying final states that include missing particles where we use the information from missing energy and momentum. In this talk, we show some of the recent results from Belle II involving missing-energy final...
