Sean Hartnoll, Cambridge University
The polarised IKKT model
The IKKT matrix model provides a holographic framework in which all spacetime dimensions are emergent. It remains poorly understood, not least because the ’timeless’ nature of the model means that the standard renormalisation group interpretation of the emergent ‘ radial’ dimension is not immediately applicable. I will discuss a supersymmetric deformation of the IKKT integral that gives a practical handle on the model. I will show how well-established phenomena, including brane polarisation in the presence of background fluxes, arise in this context and thereby allow the rudiments of a holographic dictionary to be established.
J. Richard Bond, Canadian Institute for Theoretical Astrophysics, University of Toronto
[KEK-Cosmo special colloquium] Entropy in a Coherent Universe: Quantum Information in the Action of the Cosmic SuperWeb
von Neumann of (thermal) quantum entropy fame purportedly responded to Shannon asking what his novel classical information content measure should be called: paraphrasing, entropy, nobody understands it anyway. Nowadays information entropy and thermal entropy have merged as ideas, and expanded to encompass phase info as well as counting info, aka quantum information. Its development and transport through all of the great cosmic epochs of instability accompanying transitions of phase is a unifying story of the Universe. This is a big topic which I will meander through, from the speculative emergence of coherence, through an inflation era, its preheating end in the matter-entropy burst, with attention on the cosmic neutrino background decoupling, cosmic photon thermal decoupling and its Compton scattering decoupling, and entropy development and transport in the gravitationally-unstable nonlinear cosmic web. With applications to observable entropic relics and the cosmic parameters we derive from them, such as the CnuB, CMB, the cosmic infrared background, line intensity mapping, and the thermal state of clusters, groups and the IGM. Whew, and that’s not all: one quest is for information-laden Planck-epoch non- Gaussianities, scalar and tensor, beyond Planck the satellite, and towards LiteBird.
Tomoya Kinugawa, Shinshu University
Gravitational waves from first star remnants
We calculated binary evolutions of first stars (Pop III) and showed that the typical chirp mass of Pop III binary black holes is ∼30Msun with a total mass of ∼60Msun and the maximum mass of Pop III BBH is more massive than the limit mass of the pair instability supernovae. Our result, which predicted gravitational wave events like GW150914 and GW190521, can explain the origin of massive stellar binary black hole mergers. In this talk, I will explain Pop III binary evolutions and the properties of Pop III binary black hole mergers. There is a good chance to check indirectly the existence of Pop III massive stars by gravitational waves.
Yu Hamada, DESY
Gravitational wave from current-carrying domain walls
Domain walls (DWs) are very common objects that appear in many BSM models with spontaneous breaking of discrete symmetries and have been widely studied in the context of gravitational wave observation. Depending on models, DWs can contain internal degrees of freedom such as fermionic zeromodes (like DW fermion in lattice QCD) or bosonic zeromodes. Such an object is called current-carrying DW as it can carry (dark) electric charge/current. In this talk, we will show gravitational wave spectrum radiated from current-carrying DWs can be quite different from conventional DWs. Particularly they can enhance UV regime of spectrum, increasing the detectability by future gravitational wave instruments.
宮原正也, KEK素核研・QUP
[金茶会] 半導体の技術トレンドと物理実験用ASIC開発
https://www-conf.kek.jp/kincha/
集積回路を中心とした半導体デバイスは現代の電子機器や情報化社会の根幹を支えており、物理実験においてもセンサの微細化、多チャンネル化に伴い高機能・高集積を実現する集積回路技術の重要度は日々増しています。
集積回路技術は今日まで約60年にわたりムーアの法則とも呼ばれるトランジスタの微細化と共に発展して来ました。しかしながら単純な微細化は物理的制約により終わりを迎え、今後の開発競争の見通しは困難なものとなっています。
日本国内では改めて半導体が国家の今後を左右する戦略物資として見直され、先端集積回路製造工場の誘致及び建設、並びにそれを支える人材育成の教育体制の構築と様々な動きが生じています。
本講演ではCMOS集積回路技術を中心とした半導体技術トレンドを俯瞰し、今後の物理実験に用いられるASICの開発のあり方について主観多めに論じます。
Chong-Sun Chu, National Tsing Hua University
A proposal for quantum gravity and quantum mechanics of black hole
We propose a quantum mechanical theory of quantum spaces described by large $N$ noncommutative geometry as a model for quantum gravity. The theory admits fuzzy sphere and fuzzy ellipsoid as solution. We show that these solutions reproduces precisely the horizon radius of a Schwarzschild black hole and a Kerr black hole. Moreover our quantum mechanical description gives rise to a set of microstates over these geometries, which reproduces precisely the Bekenstein-Hawking entropy of black hole. These results provide strong support that our proposed theory of quantum spaces is a plausible candidate for the theory of quantum gravity.
References:
[1] 2406.01466 [hep-th]
A Matrix Model Proposal for Quantum Gravity and the Quantum Mechanics of Black Holes
[2] 2406.12704 [hep-th]
Quantum Kerr Black Hole from Matrix Theory of Quantum Gravity
[3] Recent unpublished results.
Giacomo Landini, Valencia U
Dark Matter from strongly coupled theories dark baryons and dark pions
Understanding the nature of Dark Matter is one of the most significant open problems in particle physics and cosmology. In this talk, I will explore how Dark Matter candidates can naturally arise as composite bound states in new strongly coupled gauge sectors. I will focus on two specific realizations.
First, I will discuss baryonic Dark Matter in the context of a model for neutrino mass generation. Then, I will examine a model of dark pions, demonstrating how the inclusion of a topological theta term can induce resonant processes, which allow to reproduce the correct Dark Matter relic abundance and address the small-scale anomalies of the Lambda-CDM model.
Bruno Scheihing (MIT)
Adiabatic Hydrodynamization: a Novel Framework to Understand the Equilibration Process of non-Abelian Plasmas
Understanding the thermalization process of non-abelian plasmas is of great interest, particularly in cosmology and in relativistic heavy ion collisions. On the one hand, the dynamics of thermalization might have had important consequences at the end of the inflationary epoch in the early Universe. On the other hand, out-of-equilibrium Quantum Chromodynamics (QCD) can nowadays be studied in a repeated and systematic manner in relativistic heavy ion collisions (HICs). For the most part, HICs have been used to characterize the high-temperature phase of QCD, quark-gluon plasma, which behaves as a near-perfect fluid during the period of the collision when the temperature is above the deconfinement transition temperature. Nonetheless, our understanding of the process by which local thermal equilibrium is attained (“hydrodynamization”) in heavy ion collisions affects our interpretation of many observables in such collisions. Therefore, it is crucial to have qualitative and quantitative control over the thermalization/hydrodynamization process of QCD. In this talk, we will discuss a recent development in our understanding of the dynamics of hydrodynamization of Yang-Mills plasmas. Specifically, we focus on the weakly coupled description of a pure glue plasma in the framework of kinetic theory. Due to the nonlinear nature of the kinetic equation, finding intuitive and systematic organizing principles to study the dynamics of the distribution function starting from arbitrary initial conditions has proved to be challenging. Adiabatic Hydrodynamization is a novel framework that aims to provide such an organizing principle by identifying the long-lived solutions of the theory as the low-energy eigenstates of the time evolution operator of the theory (the “Hamiltonian”), provided that the (time-dependent) basis on which the Hamiltonian is formulated be such that the evolution is adiabatic. We work this out explicitly in a simplified version of QCD kinetic theory in a geometry motivated by HIC experiments. We conclude by laying out the prospects for studying more general kinetic theories in this framework.
Kensuke Akita (U. Tokyo)
Limits on heavy neutral leptons, Z′ bosons and majorons from high-energy supernova neutrinos
Light hypothetical particles with masses up to O(100) MeV can be produced in the core of supernovae. Their subsequent decays to neutrinos can produce a flux component with higher energies than the standard flux. We study the impact of heavy neutral leptons, Z′bosons, in particular U(1)Lμ−Lτ and U(1)B−L gauge bosons, and majorons coupled to neutrinos flavor-dependently. We obtain new strong limits on these particles from no events of high-energy SN 1987A neutrinos and their future sensitivities from observations of galactic supernova neutrinos.
濱田雄太, KEK理論センター
[金茶会] Swampland Conjecture --許されざる理論の考察