Akira Sakai

(ResearchGate, researchmap, Visionary Scientists)

 

Professor in Mathematics

Faculty of Science

Hokkaido University

 

Contents

I. Research interest

II. Research papers

III. Scientific talks

IV. Organizing scientific meetings

V. Teaching

VI. Curriculum vitae

 

 

Updated: April 13, 2021.

 

 

                               I.          Research interest（日本語版はこちら）

 

To rigorously prove various important statistical-physics phenomena.  They include phase transitions and critical behavior, associated limit theorems, and convergence to equilibrium measures and its application to combinatorial optimization.  The mathematical models I have been interested in are

 

·      the Ising model (for magnets) and the stochastic cellular automata,

·      the φ4 model (in lattice scalar-field theory),

·      self-avoiding walk (for linear polymers),

·      lattice trees (for branched polymers),

·      percolation (for random media),

·      oriented percolation and the contact process (for the spread of an infectious disease),

·      random walk with reinforcement.

 

 

                           II.          Research papers

 

1.            B.H. Fukushima-Kimura, A. Sakai, H. Toyokawa and Y. Ueda.  Stability of energy landscape.  Available soon.

 

2.            B.H. Fukushima-Kimura, S. Handa, K. Kamakura, Y. Kamijima and A. Sakai.  Mixing time and simulated annealing for the stochastic cellular automata.  Submitted.  arXiv:2007.11287.

 

3.            Akira Sakai.  Correct bounds on the Ising lace-expansion coefficients.  Submitted.  arXiv:2003.09856.

 

4.            Akira Sakai.  パーコレーションの数理2020（Percolation 2020）.  To appear in 数学（Sugaku）.

 

5.            K. Yamamoto, K. Kawamura, K. Ando, N. Mertig, T. Takemoto, M. Yamaoka, H. Teramoto, A. Sakai, S. Takamaeda-Yamazaki and M. Motomura.  STATICA: a 512-spin 0.25M-weight annealing processor with an all-spin-updates-at-once architecture for combinatorial optimization with complete spin-spin interactions.  IEEE Journal of Solid-State Circuits 56 (2021): 165–178.

 

6.            K. Yamamoto, K. Ando, N. Mertig, T. Takemoto, M. Yamaoka, H. Teramoto, A. Sakai, S. Takamaeda-Yamazaki and M. Motomura.  7.3 STATICA: a 512-spin 0.25M-weight full-digital annealing processor with a near-memory all-spin-updates-at-once architecture for combinatorial optimization with complete spin-spin interactions.  2020 IEEE International Solid-State Circuits Conference.

 

7.            Akira Sakai.  Crossover phenomena in the critical behavior for long-range models with power-law couplings.  RIMS Kokyuroku Bessatsu B79 (2020): 51–62.  arXiv:1812.10275.

 

8.            S. Handa, Y. Kamijima and A. Sakai.  A survey on the lace expansion for the nearest-neighbor models on the BCC lattice.  Taiwanese J. Math. 24 (2020): 723–784.  arXiv:1712.05573.

 

9.            S. Handa, K. Kamakura, Y. Kamijima and A. Sakai.  Finding optimal solutions by stochastic cellular automata.  arXiv:1906.06645.

 

10.        L.-C. Chen and A. Sakai.  Critical two-point function for long-range models with power-law couplings: The marginal case for d ³ dc.  Commun. Math. Phys. 372 (2019): 543–572 (the full-text view-only version).  arXiv:1808.06789.

 

11.        S. Handa, M. Heydenreich and A. Sakai.  Mean-field bound on the 1-arm exponent for Ising ferromagnets in high dimensions.  A chapter in Sojourns in Probability and Statistical Physics - I (V. Sidoravicius ed., Springer, 2019).  arXiv:1612.08809.

 

12.        A. Sakai and G. Slade.  Spatial moments for high-dimensional critical contact process, oriented percolation and lattice trees.  Electron. J. Probab. 24 (2019): no. 65, 1–18.  arXiv:1810.04011.

 

13.        Akira Sakai.  Hyperscaling for oriented percolation in 1+1 space-time dimensions.  J. Stat. Phys. 171 (2018): 462–469 (the full-text view-only version).  arXiv:1709.08291.

 

14.        T. Arae, S. Isai, A. Sakai, K. Mineta, M. Yokota-Hirai, Y. Suzuki, S. Kanaya, J. Yamaguchi, S. Naito and Y. Chiba.  Coordinated regulations of mRNA synthesis and decay during cold acclimation in arabidopsis cells.  Plant Cell Physiol. 58 (2017): 1090–1102.

 

15.        Y. Chino and A. Sakai.  The quenched critical point for self-avoiding walk on random conductors.  J. Stat. Phys. 163 (2016): 754–764.  arXiv:1508.01262.

 

16.        Akira Sakai.  Application of the lace expansion to the φ4 model.  Commun. Math. Phys. 336 (2015): 619–648.  arXiv:1403.5714.

 

17.        L.-C. Chen and A. Sakai.  Critical two-point functions for long-range statistical-mechanical models in high dimensions.  Ann. Probab. 43 (2015): 639–681.  arXiv:1204.1180.

 

18.        L.-C. Chen and A. Sakai.  Asymptotic behavior of the gyration radius for long-range self-avoiding walk and long-range oriented percolation.  Ann. Probab. 39 (2011): 507–548.  arXiv:1002.0875.

 

19.        Akira Sakai.  Large-time asymptotics of the gyration radius for long-range statistical-mechanical models.  RIMS Kokyuroku Bessatsu B21 (2011): 53–62.  arXiv:0912.5117.

 

20.        R. van der Hofstad and A. Sakai.  Convergence of the critical finite-range contact process to super-Brownian motion above the upper critical dimension: The higher-point functions.  Electron. J. Probab. 15 (2010): no. 27, 801–894.  arXiv:0809.1712.

 

21.        L.-C. Chen and A. Sakai.  Critical behavior and the limit distribution for long-range oriented percolation. II: Spatial correlation.  Probab. Theory Relat. Fields 145 (2009): 435–458.  arXiv:0804.2039.

 

22.        Akira Sakai.  Applications of the lace expansion to statistical-mechanical models.  A chapter in Analysis and Stochastics of Growth Processes and Interface Models (P. Mörters et al. eds., Oxford University Press, 2008).

 

23.        M. Heydenreich, R. van der Hofstad and A. Sakai.  Mean-field behavior for long- and finite range Ising model, percolation and self-avoiding walk.  J. Stat. Phys. 132 (2008): 1001–1049.  arXiv:0712.0312.

 

24.        L.-C. Chen and A. Sakai.  Critical behavior and the limit distribution for long-range oriented percolation. I.   Probab. Theory Relat. Fields 142 (2008): 151–188.  arXiv:0703455.

 

25.        Akira Sakai.  Diagrammatic bounds on the lace-expansion coefficients for oriented percolation.  arXiv:0708.2897.

 

26.        M. Holmes and A. Sakai.  Senile reinforced random walks.  Stoch. Proc. Appl. 117 (2007): 1519–1539.

 

27.        Akira Sakai.  Lace expansion for the Ising model.  Commun. Math. Phys. 272 (2007): 283–344.  arXiv:math-ph/0510093.

 

28.        R. van der Hofstad and A. Sakai.  Critical points for spread-out self-avoiding walk, percolation and the contact process above the upper critical dimensions.  Probab. Theory Relat. Fields 132 (2005): 438–470.  arXiv:math/0402050.

 

29.        Akira Sakai.  Mean-field behavior for the survival probability and the percolation point-to-surface connectivity.  J. Stat. Phys. 117 (2004): 111–130.

 

30.        R. van der Hofstad and A. Sakai.  Gaussian scaling for the critical spread-out contact process above the upper critical dimension.  Electron. J. Probab. 9 (2004): no. 24, 710–769.  arXiv:math/0402049.

 

31.        M. Holmes, A.A. Járai, A. Sakai and G. Slade.  High-dimensional graphical networks of self-avoiding walks.  Canad. J. Math. 56 (2004): 77–114.

 

32.        Akira Sakai.  Hyperscaling inequalities for the contact process and oriented percolation.  J. Stat. Phys. 106 (2002): 201–211.

 

33.        Akira Sakai.  Mean-field critical behavior for the contact process.  J. Stat. Phys. 104 (2001): 111–143.

 

 

                       III.          Scientific talks

 

Year 2022

 

1.       TBA.

·     100 Years of the Ising Model (May 30– June 3). Institut des Hautes Études Scientifiques, France.

 

Year 2020

 

1.       Mixing time and simulated annealing for the stochastic cellular automata (SCA).

·     International Workshop on Microstructure-based Global Analysis and Its Related Topics (November 7). Hokkaido University, Japan.

 

Year 2019

 

1.       Finding optimal solutions by stochastic cellular automata.

·     7th Wellington Workshop in Probability and Mathematical Statistics (December 5–7). Victoria University of Wellington, New Zealand.

·     Workshop on Probabilistic Methods in Statistical Mechanics of Random Media and Random Fields (May 27–31). Universiteit Leiden, the Netherlands.

·     AIMaP 1-day Workshop (March 26). RIES, Hokkaido University, Japan.

 

2.       Critical two-point function for long-range models with power-law couplings: The marginal case for d ³ dc.

·     The 12th MSJ-SI “Stochastic Analysis, Random Fields and Integrable Probability” (July 31–August 9). Kyushu University, Japan.

·     Seminar in Statistics (January 16). The University of Auckland, New Zealand.

 

Year 2018

 

1.       Critical two-point function for long-range models with power-law couplings: The marginal case for d ³ dc.

·     17th International Symposium “Stochastic Analysis on Large-scale Interacting Systems”  (November 5–8). RIMS, Kyoto University, Japan.

·     High-dimensional Critical Phenomena in Random Environments (September 24–26). The University of Bristol, UK.

·     2018 Spring Probability Workshop (June 4–8). Academia Sinica, Taiwan.

 

2.       Hyperscaling for oriented percolation in 1+1 space-time dimensions.

·     Rikkyo Math Phys Seminar (May 23). Rikkyo University, Japan

·     NUS Probability Seminar (February 12). National University of Singapore, Singapore.

 

Year 2017

 

1.       Hyperscaling for oriented percolation in 1+1 space-time dimensions.

·     NTU Math Colloquium (November 27). National Taiwan University, Taiwan.

 

2.       強磁性イジング模型の相転移・臨界現象に関する研究の最近の動向（Recent progress in researches on phase transitions and critical behavior for Ising ferromagnet）.

·     MSJ Fall Meeting (September 11–14). Yamagata University, Japan.

 

3.       Critical behavior for oriented percolation: From a mathematically rigorous standpoint.

·     Summer School in Mathematical Physics (August 25–27). The University of Tokyo, Japan.

 

4.       The lace expansion for self-avoiding walk and percolation on the BCC lattice.

·     Seminar on Probability (July 18). Osaka University, Japan.

 

5.       Mean-field bound on the 1-arm exponent for high-dimensional Ising ferromagnets.

·     Physical and Mathematical Approaches to Interacting Particle Systems – In Honer of 70th Birthday of Herbert Spohn (January 11–12). Tokyo Institute of Technology, Japan.

 

Previous years

 

 

                        IV.          Organizing scientific meetings

 

Year 2022

 

1.            The 3rd workshop on Universality and Scaling Limits in Probability and Statistical Mechanics. Hokkaido University, Japan.

 

Year 2021

 

1.            PRIMA 2021: Pacific Rim Mathematical Association Congress 2021 (December 5–10, 2021). University of British Columbia, Canada.

 

2.            The RIMS Workshop “Rigorous Statistical Mechanics and Related Topics III” (November 16–19, 2021). RIMS, Kyoto University, Japan.

 

3.            The 10th World Congress in Probability and Statistics (July 19–23, 2021). Seoul National University, South Korea.

 

Year 2020 and before

 

1.            The RIMS Workshop “Rigorous Statistical Mechanics and Related Topics II” (November 24–27, 2020). Zoom.

 

2.            The RIMS Workshop “Rigorous Statistical Mechanics and Related Topics” (November 18–21, 2019). RIMS, Kyoto University, Japan.

 

3.            The 1-day workshop “Recent Progress in Probability Theory and Its Applications” (July 28, 2017). Hokkaido University, Japan.

 

4.            2017 Spring Probability Workshop (March 6–8, 2017). Academia Sinica, Taiwan.

 

5.            The 2nd workshop on Universality and Scaling Limits in Probability and Statistical Mechanics (August 5–9, 2013). Hokkaido University, Japan.

 

6.            International Workshop on Potential Theory (February 4, 2013). Hokkaido University, Japan.

 

7.            The RIMS workshop “Applications of Renormalization Group Methods in Mathematical Sciences” (September 12–14, 2011). Kyoto University, Japan.

 

8.            The SPA Satellite workshop “Universality and Scaling Limits in Probability and Statistical Mechanics” (August 30–September 3, 2010). Hokkaido University, Japan.

 

 

                            V.          Teaching (April 2021 – February 2022)

 

1st semester

Monday

Tuesday

Wednesday

Thursday

Friday

8:45 – 10:15

N.A.

科・技の世界

N.A.

N.A.

確率・統計入門

10:30 – 12:00

N.A.

N.A.

数理科学基礎

N.A.

N.A.

12:00 – 13:00

Lunch

Lunch

Lunch

Lunch

Lunch

13:00 – 14:15

N.A.

梁

上島

N.A.

守屋

14:25 – 15:40

N.A.

野田

上島

N.A.

丹菊

15:50 – 17:05

SCA (16:30 – 18:00)

松沼

N.A.

F.M.

田中

17:15 – 18:30

Group (18:15 – 19:45)

河本

O.H.

F.M.

N.A.

                                                (Lectures; Seminars; Faculty Meetings; Office Hour; Not Available )

 

1.      Seminars @ Science Bldg 3-413.

·     B4 Seminar (野田) on Mathematics in Phase Transitions and Critical Phenomena.

·     M1 Seminar (松沼) on Sandpile Models.

·     M1 Seminar (丹菊) on Stochastic Differential Equations.

·     M2 Seminar (梁) on ???.

·     M2 Seminar (守屋) on The Continuous-time Lace Expansion.

·     M2 Seminar (田中) on Stochastic Calculus for Finance II.

·     D1 Seminar (河本) on Introduction to a Renormalization Group Method.

·     PD Seminar (上島 @ Science Bldg 3-513) on the quantum Ising model.

·     CREST SCA Seminar (Fukushima-Kimura, 上島, 河本 @ Science Bldg 3-513).

·     CREST Group Seminar (Fukushima-Kimura, 青木, 石橋, 河本, 齋藤).

 

2.      科学・技術の世界：数学のたのしみ（The World of Science and Technology） (Tuesdays 8:45–10:15 @ Multimedia Education Bldg ???).

 

3.      確率・統計入門（Introduction to Probability and Statistics） (Fridays 8:45–10:15 @ Science Bldg 5-203).

 

4.      数理科学基礎（Basic Mathematical Science） (Wednesdays 10:30–12:00 @ Science Bldg 3-309).

 

 

                        VI.          Curriculum vitae

 

·     August 2020 – present

Associate editor of Taiwanese Journal of Mathematics.

 

·     March 2020 – present

Associate editor of Mathematical Physics, Analysis and Geometry.

 

·     February 2020 – present

Professor in Mathematics, Faculty of Science, Hokkaido University, Japan.

 

·     September 2015 – August 2019

Councilor of the Bernoulli Society.

 

·     Excellent Teachers 2018, 2015, 2012, 2011

The Hokkaido University President’s Award for Teaching Excellence in 2013 and in 2012.

 

·     April 2011 – January 2020

Associate professor in Mathematics, Faculty of Science, Hokkaido University, Japan.

 

·     March 2008 – March 2011

Tenure-track assistant professor of Creative Research Institution SOUSEI, Hokkaido University, Japan.

 

·     April 2006 – February 2008

Lecturer in Probability of the Department of Mathematical Sciences, the University of Bath, UK.

 

·     April 2004 – March 2006

Postdoctoral researcher of Wiskunde en Informatica, Technische Universiteit Eindhoven (TU/e), the Netherlands.

 

·     January 2003 – March 2004

Postdoctoral researcher of the Interacting Stochastic Systems (ISS) group, EURANDOM, the Netherlands.

 

·     January 2001 – December 2002

Postdoctoral researcher of the Department of Mathematics, the University of British Columbia, Canada.

 

·     April 1996 – December 2000

Ph.D. study in Applied Physics, Tokyo Institute of Technology, Japan.

Awarded Ph.D. for the thesis “Analyses of the Critical Behavior for the Contact Process based on a Percolation Structure” supervised by Takashi Hara.

 

·     April 1994 – March 1996

Master study in Applied Physics, Tokyo Institute of Technology, Japan.

Awarded M.Sc. for the thesis “Approach to Fractal Growth Phenomena” supervised by Takashi Hara.

 

·     April 1990 – March 1994

Undergraduate study in Applied Physics, Tokyo Institute of Technology, Japan.

Awarded B.Sc. for the thesis “Recurrent in the Plane, Transient in Space” supervised by Kohei Uchiyama.