## Future seminars

Seminar information archive ～12/05｜Today's seminar 12/06 | Future seminars 12/07～

### 2022/12/08

#### Information Mathematics Seminar

16:50-18:35 Room #123 (Graduate School of Math. Sci. Bldg.)

Near-term quantum algorithms and quantum error mitigation (Japanese)

**Suguru Endo**(NTT)Near-term quantum algorithms and quantum error mitigation (Japanese)

[ Abstract ]

The current or near-term quantum computing devices are still small and noisy. In this talk, I will near-term quantum algorithms and quantum error mitigation for improving computation accuracy.

The current or near-term quantum computing devices are still small and noisy. In this talk, I will near-term quantum algorithms and quantum error mitigation for improving computation accuracy.

### 2022/12/12

#### Seminar on Geometric Complex Analysis

10:30-12:00 Room #128 (Graduate School of Math. Sci. Bldg.)

$L^2$-extension index and its applications (Japanese)

https://forms.gle/hYT2hVhDE3q1wDSh6

**Takahiro Inayama**(Tokyo University of Science)$L^2$-extension index and its applications (Japanese)

[ Abstract ]

In this talk, we introduce a new concept of $L^2$-extension indices. By using this notion, we propose a new way to study the positivity of curvature. We prove that there is an equivalence between how sharp the $L^2$-extension is and how positive the curvature is. As applications, we study Prekopa-type theorems and the positivity of a certain direct image sheaf.

[ Reference URL ]In this talk, we introduce a new concept of $L^2$-extension indices. By using this notion, we propose a new way to study the positivity of curvature. We prove that there is an equivalence between how sharp the $L^2$-extension is and how positive the curvature is. As applications, we study Prekopa-type theorems and the positivity of a certain direct image sheaf.

https://forms.gle/hYT2hVhDE3q1wDSh6

### 2022/12/13

#### Algebraic Geometry Seminar

10:30-11:30 Room #ハイブリッド開催/002 (Graduate School of Math. Sci. Bldg.)

The speaker will give his talk by Zoom

TBA (日本語)

The speaker will give his talk by Zoom

**山岸亮**(NTU)TBA (日本語)

[ Abstract ]

TBA

TBA

#### Operator Algebra Seminars

16:45-18:15 Room #128 (Graduate School of Math. Sci. Bldg.)

Entropy in QFT

[ Reference URL ]

https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm

**Feng Xu**(UC Riverside)Entropy in QFT

[ Reference URL ]

https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm

#### Tuesday Seminar on Topology

17:30-18:30 Online

Pre-registration required. See our seminar webpage.

Spectral convergence in geometric quantization on K3 surfaces (JAPANESE)

https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html

Pre-registration required. See our seminar webpage.

**Kota Hattori**(Keio University)Spectral convergence in geometric quantization on K3 surfaces (JAPANESE)

[ Abstract ]

In this talk I will explain the geometric quantization on K3 surfaces from the viewpoint of the spectral convergence. We take a special Lagrangian fibrations on the K3 surfaces and a family of hyper-Kähler structures tending to large complex structure limit and show a spectral convergence of the d-bar-Laplacians on the prequantum line bundle to the spectral structure related to the set of Bohr-Sommerfeld fibers.

[ Reference URL ]In this talk I will explain the geometric quantization on K3 surfaces from the viewpoint of the spectral convergence. We take a special Lagrangian fibrations on the K3 surfaces and a family of hyper-Kähler structures tending to large complex structure limit and show a spectral convergence of the d-bar-Laplacians on the prequantum line bundle to the spectral structure related to the set of Bohr-Sommerfeld fibers.

https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html

#### Tuesday Seminar of Analysis

16:00-17:30 Room #126 (Graduate School of Math. Sci. Bldg.)

Continuum limit problem of discrete Schrödinger operators on square lattices (Japanese)

https://forms.gle/CRha8hydEuXzh71S7

**TADANO Yukihide**(Tokyo University of Science)Continuum limit problem of discrete Schrödinger operators on square lattices (Japanese)

[ Abstract ]

We consider discrete Schrödinger operators on the square lattice with its mesh size very small. The aim of this talk is to introduce the rigorous setting of continuum limit problems in the view point of operator theory and then to give its proof for the above operators, the one of which is defined on the vertices and the other of which is defined on the edges. This talk is based on joint works with Shu Nakamura (Gakushuin University) and Pavel Exner (Czech Academy of Science, Czech Technical University).

[ Reference URL ]We consider discrete Schrödinger operators on the square lattice with its mesh size very small. The aim of this talk is to introduce the rigorous setting of continuum limit problems in the view point of operator theory and then to give its proof for the above operators, the one of which is defined on the vertices and the other of which is defined on the edges. This talk is based on joint works with Shu Nakamura (Gakushuin University) and Pavel Exner (Czech Academy of Science, Czech Technical University).

https://forms.gle/CRha8hydEuXzh71S7

### 2022/12/20

#### Algebraic Geometry Seminar

9:30-10:30 Room #ハイブリッド開催/002 (Graduate School of Math. Sci. Bldg.)

The speaker will give his talk by Zoom

TBA (English)

The speaker will give his talk by Zoom

**Takumi Murayama**(Purdue)TBA (English)

[ Abstract ]

English

English

#### Tuesday Seminar of Analysis

16:00-17:30 Room #126 (Graduate School of Math. Sci. Bldg.)

A commentary on J. Boman's recent two related results about the support of a distribution and its analyticity, and a special relationship between Radon transformations and ellipsoidal regions (Japanese)

https://forms.gle/BpciRTzKh9FPUV8D7

**KATAOKA Kiyoomi**(The University of Tokyo)A commentary on J. Boman's recent two related results about the support of a distribution and its analyticity, and a special relationship between Radon transformations and ellipsoidal regions (Japanese)

[ Abstract ]

Jan Boman's (Stockholm Univ.) recent two papers:

[1], Regularity of a distribution and of the boundary of its support, The Journal of Geometric Analysis vol.32, Article number: 300 (2022).

[2], A hypersurface containing the support of a Radon transform must be an ellipsoid. II: The general case; J. Inverse Ill-Posed Probl. 2021; 29(3): 351–367.

In [1] he proved "Let $f(x_1,…,x_n,y)$ be a non-zero distribution with support in a $C^1$ surface $N=\{y=F(x)\}$. If $f(x,y)$ is depending real analytically on x-variables, then $F(x)$ is analytic". As an application, he reinforced the main result of [2]. These results are obtained essentially by means of matrix algebra and a number theoretic method.

[ Reference URL ]Jan Boman's (Stockholm Univ.) recent two papers:

[1], Regularity of a distribution and of the boundary of its support, The Journal of Geometric Analysis vol.32, Article number: 300 (2022).

[2], A hypersurface containing the support of a Radon transform must be an ellipsoid. II: The general case; J. Inverse Ill-Posed Probl. 2021; 29(3): 351–367.

In [1] he proved "Let $f(x_1,…,x_n,y)$ be a non-zero distribution with support in a $C^1$ surface $N=\{y=F(x)\}$. If $f(x,y)$ is depending real analytically on x-variables, then $F(x)$ is analytic". As an application, he reinforced the main result of [2]. These results are obtained essentially by means of matrix algebra and a number theoretic method.

https://forms.gle/BpciRTzKh9FPUV8D7

#### Operator Algebra Seminars

16:45-18:15 Online

Band width and the Rosenberg index

https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm

**Yosuke Kubota**(Shinshu Univ.)Band width and the Rosenberg index

[ Abstract ]

Band width is a concept recently proposed by Gromov. It is based on the idea that when a certain band (i.e., manifold with two boundaries) is openly immersed to a target manifold M with positive scalar curvature metric, then its width is bounded by a uniform constant called the band width of M. A qualitative consequence is that infiniteness of the band width of M obstructs to positive scalar curvature.

In this talk, infiniteness of a version of the band width, Zeidler's KO-band width, is dominated as a PSC obstruction by an existing obstruction, the Rosenberg index. This answers to a conjecture by Zeidler.

[ Reference URL ]Band width is a concept recently proposed by Gromov. It is based on the idea that when a certain band (i.e., manifold with two boundaries) is openly immersed to a target manifold M with positive scalar curvature metric, then its width is bounded by a uniform constant called the band width of M. A qualitative consequence is that infiniteness of the band width of M obstructs to positive scalar curvature.

In this talk, infiniteness of a version of the band width, Zeidler's KO-band width, is dominated as a PSC obstruction by an existing obstruction, the Rosenberg index. This answers to a conjecture by Zeidler.

https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm

### 2022/12/22

#### Information Mathematics Seminar

16:50-18:35 Room #123 (Graduate School of Math. Sci. Bldg.)

Theory of fault-tolerant quantum computing I (Japanese)

**Yasunari Suzuki**(NTT)Theory of fault-tolerant quantum computing I (Japanese)

[ Abstract ]

To demonstrate reliable quantum computing, we need to integrate quantum error correction techniques and achieve fault-tolerant quantum computing. In this seminar, I will explain the basic of fault-tolerant quantum computing and recent progress towards its experimental realization.

To demonstrate reliable quantum computing, we need to integrate quantum error correction techniques and achieve fault-tolerant quantum computing. In this seminar, I will explain the basic of fault-tolerant quantum computing and recent progress towards its experimental realization.

### 2023/01/10

#### Algebraic Geometry Seminar

10:30-11:30/12:00 Room #002 (Graduate School of Math. Sci. Bldg.)

TBA (日本語)

**Akihiro Higashitani**(Osaka/Dept. of Inf. )TBA (日本語)

[ Abstract ]

TBA

TBA

### 2023/01/16

#### Seminar on Geometric Complex Analysis

10:30-12:00 Room #128 (Graduate School of Math. Sci. Bldg.)

TBA (Japanese)

https://forms.gle/hYT2hVhDE3q1wDSh6

**Takayuki Koike**(Osaka Metropolitan University)TBA (Japanese)

[ Abstract ]

TBA

[ Reference URL ]TBA

https://forms.gle/hYT2hVhDE3q1wDSh6