Gary Shiu, UW Madison
The String Genome Project
Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom Considerations from both the Landscape and the Swampland suggest that 1) consistent quantum theories of gravity are rare in the space of all possible theories; 2) the number of consistent string vacua is enormous but finite. In light of these properties of quantum gravity, exhaustive searches for realistic vacua would not be feasible
Considerations from both the Landscape and the Swampland suggest that 1) consistent quantum theories of gravity are rare in the space of all possible theories; 2) the number of consistent string vacua is enormous but finite. In light of these properties of quantum gravity, exhaustive searches for realistic vacua would not be feasible
while random sampling would not be representative of the Landscape. In this talk, I will discuss how AI can be used to search for optimal solutions in string theory, to enumerate the exact number of solutions in regions of the Landscape and to discover structures therein, and to generate new Calabi-Yau compactifications.
Hidetoshi Omiya, Kyoto U
Impact of the self-interaction on the axion cloud and its gravitational wave signatures
Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
The superradiant instability provides a promising avenue for detecting ultra-light axions through the formation of axion clouds around black holes. The way to observe the axion cloud includes observation of the spin of the black hole and the gravitational waves.To effectively observe these axions, it is crucial to have a precise understanding of the cloud’s evolution and its observable signatures. In this talk, I will discuss the impact of axion self-interaction on both the evolution of the cloud and its observational signatures. In particular, I will show that the self-interaction can produce signals in the different frequency bands.
Toru Kojo, KEK
[KEK-JAEA Joint Seminar] A quarkyonic matter model for dense QCD and hyperon problems
Hybrid On-site: Room 116, KEK Tokai campus Online: Zoom
Recent neutron star observations combined with the nuclear constraints suggest that QCD matter quickly stiffens at density close to nuclear matter density. We argue that the stiffening is triggered by a transition from nuclear to quark matter. The concept of quarkyonic matter captures relevant features necessary to understand the stiffening. We present an ideal model of quarkyonic matter and apply it to isospin symmetric and a matter of neutral baryons including the strangeness. We argue how the quark description mitigates the hyperon problems in neutron star constraints.
Justin Kaidi, Kyushu U
Non-Supersymmetric Heterotic Branes
Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
The common statement that any consistent quantum gravity theory contains dynamical objects with all possible charges suggests that there are still a number of hitherto-unidentified branes in string theory. In this talk I will discuss four of these new branes, focusing on heterotic string theories. The focus of the discussion will be on the relationship between these branes and the lower-dimensional vacua obtained by closed string tachyon condensation in the ten-dimensional, non-supersymmetric heterotic string theories.
Andrew Jaffe, Imperial
The search for the topology of the Universe has only just begun
Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
The topology of the Universe is not directly constrained by general relativity, and quantum mechanics may indeed prefer the creation of small Universes with nontrivial topologies. Large-scale cosmological measurements have shown no direct evidence of the patterns that would be induced in these cases, and the shortest distance around the Universe through us is unlikely to be much larger than the horizon diameter if microwave background anomalies are due to cosmic topology. I will discuss observational constraints from the lack of matched temperature circles in the microwave background which nonetheless leave many possibilities for such topologies, and further possibilities for their detection through large-scale correlations. I will also show that the large scale structure of space, rather than parity-violating microphysics, induces CMB parity violation in some topologies. Searches or topology signatures in observational data over the large space of possible topologies pose a formidable computational challenge, but is crucial for our understanding of the Universe.
Soichiro Shimamori, Osaka University
Non-invertible duality defect and fusion algebras in conformal field theories
Hybrid On-site: Kenkyu honkan, Seminar room Online: Zoom We study non-invertible duality symmetries by gauging a diagonal subgroup of a non-anomalous U(1) × U(1) global symmetry. In
We study non-invertible duality symmetries by gauging a diagonal subgroup of a non-anomalous U(1) × U(1) global symmetry. In
particular, we employ the half-space gauging to c=2 bosonic torus conformal field theory (CFT) in two dimensions and pure U(1) × U(1) gauge theory in four dimensions. In c=2 bosonic torus CFT, we show that the non-invertible symmetry obtained from the diagonal gauging becomes emergent on an irrational CFT point. We also calculate the fusion rules concerning the duality defect. We find out that the fusion algebra is non-commutative. We also obtain a similar result in pure U(1) × U(1) gauge theory in four dimensions. This presentation is based on the joint work with Yuta Nagoya [arXiv: 2309.05294, hep-th] .
西内満美子, QST関西量子科学研究所
[金茶会] レーザー駆動イオン加速研究−小型のイオン加速器実現に向けて
4号館セミナーホール リモート会場：JRB2階大会議室、仁科記念棟106室 https://www-conf.kek.jp/kincha/
https://www-conf.kek.jp/kincha/
高強度レーザーと物質との相互作用により生成される相対論的プラズマは、高エネルギー粒子の発生源として認識されてから四半世紀が経とうとしている。発生するイオンビームの特徴が既存加速器からのイオンビームの特徴と異なるため、小型の加速器を含む、様々な応用先が提唱されてきており、それに向けたビームの良質化の研究が世界において精力的に行われている。本講演では、このレーザー駆動イオン加速研究に関し、歴史、背景、世界的な動向、最先端研究についてご紹介する。
Sean Hartnoll, Cambridge University
The polarised IKKT model
Online (Zoom)
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
Seminar room, 3 go-kan
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
Hybrid On-site: Seminar room, Kenkyu honkan 3F Online: Zoom
