Junsei Tokuda, Ibs
Swampland program from amplitudes: gravitational positivity bounds
Hybrid On-site: Kenkyu honkan Seminar room 321, 322 Online: Zoom
It is interesting if there exist non-trivial relations between ultraviolet complete quantum gravity and its low energy effective field theories (EFTs). Such relations are so-called swampland conditions. In this talk, we will develop a method to derive swampland conditions by extending so-called S-matrix positivity bounds to gravitational context. In our formulation, several working assumptions on quantum gravity S-matrix such as unitarity and the Reggeization of graviton exchange are imposed. We will then discuss the implications of positivity bounds on gravitational EFTs. First, we will demonstrate that our bounds are indeed satisfied in the Standard Model. Next, we will show that our bounds provide strong constraints on dark photon models which can be tested against on-going future experiments. This implies the possibility of probing quantum gravity from low-energy observables and the phenomenological importance of studying the properties of quantum gravity S-matrix.
Kyohei Mukaida, KEK
[QCD theory Seminar] Chiral asymmetry in the early Universe
Online (Zoom)
Since the SM model is a chiral theory, asymmetries in matter generically result in chiral asymmetries. Nevertheless, the effect of the primordial chiral asymmetry is often neglected in the study of the early Universe because the baryon asymmetry is tiny. In this talk, I will discuss some examples where the chiral asymmetry plays essential roles, in particular in the context of baryogenesis.
小野 寛太, 大阪大学
[KEK連携コロキウム] 量子ビーム計測の自律化
ハイブリッド形式 : オンライン (Zoom) + セミナールーム（研究本館321)
量子ビーム計測は物性物理学から生命科学までの広範な自然科学分野で重要な役割を果たしている。計測やデータ解析を合理的・高精度で行う計測インフォマティクスに関する研究が近年進展しているが、われわれは現状の計測・解析に熟練者の介在が必須であることに着目し、自律的な計測、すなわち人間の介在なく計測から知識を抽出することを目指した研究を行なっている。講演では、合理的な計測実験計画、実験終了の自動判定、計測データの自動解析について紹介する。
Hidenori Fukaya, Osaka University
Curved domain-wall fermion and its anomaly inflow
Online (Zoom) https://kds.kek.jp/event/44588/ We consider a fermion system on a square lattice, where a curved domain-wall is assigned to the mass term. In a similar way to the standard flat domain-wall fermion, chiral edge modes appear at the wall. These edge-localized modes feel gravity, through the induced spin connection or metric due to the Einstein’s equivalence principle.
We consider a fermion system on a square lattice, where a curved domain-wall is assigned to the mass term. In a similar way to the standard flat domain-wall fermion, chiral edge modes appear at the wall. These edge-localized modes feel gravity, through the induced spin connection or metric due to the Einstein’s equivalence principle.
In the cases of circle $S^1$ and sphere $S^2$ domain-walls embedded into higher dimensional square lattices of one dimension higher, we numerically confirm the existence of the edge-localized modes and the effect of gravity encoded in the spectrum. With $U(1)$ link variables, we also find a good consistency to the anomaly inflow described by the Atiyah-Patodi-Singer index theorem in the continuum theory. This talk is based on a work with Shoto Aoki, https://arxiv.org/abs/2203.03782 and some preliminary results.
David J.E. Marsh, King's College London
[JpDe Joint Seminar] Axion Miniclusters: Recent Progress and Open Problems
Online (Zoom)
If the Peccei Quinn symmetry is broken after inflaiton, then axions are produced by the decay of topological defects. This scenario is attractive, since the axion mass is in principle predictable from the relic density, and favours the range ~0.1-10 meV. Miniclusters offer a route to probe this scenario astrophysically. Miniclusters are formed from the overdensities in the axion field left over after the topological defects decay. I will describe recent efforts to understand the mass distribution and density profiles of miniclusters, using theory and simulation. I will also describe efforts to test the minicluster scenario using gravitational microlensing, and radio transients. Open problems surround both scenarios, related to the possible existence and survival fraction of the densest miniclusters.
Niklas Mueller, Univ. of Washington
[QCD theory Seminar] QCD meets Quantum Information Science -- Thermalization of Gauge Theories from their Entanglement Spectrum
Online (Zoom)
The possibility to simulate quantum many-body systems with digital quantum computers and analog devices is an exciting opportunity for high energy and nuclear physics. One example is Entanglement Structure (ES), first explored in the context of non-Abelian fractional quantum Hall states, but largely unexplored for gauge theories and high energy and nuclear physics. ES is crucial e.g., to understand thermalization of the quark gluon plasma in ultra-relativistic heavy ion collisions, or the structure of QCD bound states in deeply inelastic scattering (DIS) at the future Electron-Ion Collider. To illustrate this, I will show how I used Entanglement Structure and Entanglement Tomography to gain insight into quantum thermalization of strongly-coupled gauge theories, which proceeds in characteristic stages and reveals quantum phenomena remarkably similar to their classical counterparts: chaos, turbulence and universality.
Miguel Montero, Harvard University
New String Theories from Discrete Theta Angles
Online (Zoom) https://kds.kek.jp/event/44336/
Topological couplings play a prominent role in our understanding of field theories, but their role in string compactifications is much less understood. I explore an example in compactifications of type IIB string theory with sixteen supercharges, showing that they lead to previously unknown components of moduli space in nine, eight, and seven dimensions. I also explain why a similar construction fails to produce a new string theory in ten dimensions. The new components of moduli space thus constructed feature an incomplete lattice of BPS strings, which has implications for a number of Swampland constraints.
Aleksey Cherman, Univ. of Minnesota
[QCD theory Seminar] 1-form symmetry and large N QCD
Online (Zoom)
The most modern way to understand quark confinement involves the notion of `1-form symmetry’. The reason we care about quark confinement is of course because of its implications for real-world QCD, but unfortunately confinement is believed to be only an approximate concept in the real world, so it is not tied to any exact symmetries. However, confinement is supposed to become well-defined in the large N limit of QCD, and so one might expect large N QCD to have a Z_N 1-form symmetry. However, to our surprise, in recent work we found some severe obstructions to the conjecture that large N QCD has a Z_N 1-form symmetry. Our results suggest that a symmetry-based understanding of (approximate) confinement in QCD may require some further generalization of the notion of generalized global symmetries.
Tomohiro Ishizu, Kansai University
[KEK IPNS-IMSS-QUP Joint Colloquium] Empirical approaches to study aesthetic experiences -an introduction to neuroaesthetics-
Online (Zoom)
Art and aesthetic experiences enrich our daily lives. It may appear distant from the empirical sciences at first glance, but it shares similar goals and is closely related to them in that it explores perception and engages with the workings of the mind. Neuroaesthetics is a discipline that studies the relationship between brain function and aesthetic experience (e.g., beauty, ugliness, being moved, sublime) as well as between cognitive processes and artistic activity (e.g. appreciation of artworks, artistic critique, creativity) using empirical methods from cognitive neuroscience. It is an interdisciplinary field that includes researchers from psychology, neuroscience, philosophy, art, art history, to welfare engineering. Following an overview of basic cognitive neuroscience research findings on aesthetic judgements such as beauty and ugliness, I will present research on more complex aesthetic experiences beyond simple beauty, such as sorrow and the sublime. Through these, I hope to explore what beauty means to humanity from a neuroaesthetics point of view.
Naritaka Oshita, RIKEN
Probing gravity with ringing black holes
Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoomhttps://kds.kek.jp/event/44132/
