Akira Sakaiiβˆδ@“Nj

(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

 

 

Last updated on February 16, 2024.

 

 

                        I.       Research interesti“ϊ–{Œκ”Ε‚Ν‚±‚Ώ‚ηj

 

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 ƒΣ4 model (in lattice scalar-field theory),

·     self-avoiding walk (for linear polymers),

·     lattice trees and lattice animals (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.         Akira Sakai.  Hugo Duminil-CopinŽ‚Μ‹ΖΡ (Work of Hugo Duminil-Copin).  ”Šw (Sugaku) 76 (2024):48–60.

 

2.         N. Kawamoto and A. Sakai.  Spread-out limit of the critical points for lattice trees and lattice animals in dimensions d ˃ 8.  Comb. Probab. Comput., 33 (2024): 238–269.  arXiv:2205.09451.

 

3.         B.H. Fukushima-Kimura, N. Kawamoto, E. Noda and A. Sakai.  Mathematical aspects of the digital annealerfs simulated annealing algorithm.  J. Stat. Phys., 190 (2023): Article 190.  arXiv:2303.08392.

 

4.         Y. Kamijima and A. Sakai.  Stability of the phase transition and critical behavior of the Ising model against quantum perturbation.  RIMS Kokyuroku, 2246 (2023): Article 2.

 

5.         B.H. Fukushima-Kimura, S. Handa, K. Kamakura, Y. Kamijima, K. Kawamura and A. Sakai.  Mixing time and simulated annealing for the stochastic cellular automata.  J. Stat. Phys., 190 (2023): Article 79.  arXiv:2007.11287.

 

6.         B.H. Fukushima-Kimura, Y. Kamijima, K. Kawamura and A. Sakai.  Stochastic optimization: Glauber dynamics versus stochastic cellular automata.  Transactions of the Institute of Systems, Control and Information Engineers 36 (2023): 9–16.  arXiv:2211.06809.

 

7.         Akira Sakai.  ƒp[ƒRƒŒ[ƒVƒ‡ƒ“‚̐”— 2020 (Percolation 2020).  ”Šw (Sugaku) 74 (2022): 253–279.

 

8.         Akira Sakai.  Correct bounds on the Ising lace-expansion coefficients.  Commun. Math. Phys., 392 (2022): 783–823 (the full-text view-only version).  arXiv:2003.09856.

 

9.         B.H. Fukushima-Kimura, Y. Kamijima, K. Kawamura and A. Sakai.  Stochastic optimization via parallel dynamics: rigorous results and simulations.  Proceedings of the ISCIE International Symposium on Stochastic Systems Theory and its Applications 2022 (2022): 6571.

 

10.      B.H. Fukushima-Kimura, A. Sakai, H. Toyokawa and Y. Ueda.  Stability of energy landscape for Ising models.  Physica A, 583 (2021): 126208.  arXiv:2105.00449.

 

11.      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.

 

12.      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.

 

13.      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.

 

14.      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.

 

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

 

16.      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): 543572 (the full-text view-only version).  arXiv:1808.06789.

 

17.      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.

 

18.      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.

 

19.      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.

 

20.      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.

 

21.      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.

 

22.      Akira Sakai.  Application of the lace expansion to the ƒΣ4 model.  Commun. Math. Phys., 336 (2015): 619–648.  arXiv:1403.5714.

 

23.      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.

 

24.      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.

 

25.      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.

 

26.      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.

 

27.      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.

 

28.      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).

 

29.      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.

 

30.      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.

 

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

 

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

 

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

 

34.      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.

 

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

 

36.      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.

 

37.      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.

 

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

 

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

 

 

                 III.       Scientific talks

 

Year 2024

 

1.      TBA.

·    Taiwan Probability Workshop 2024 (June 3–7). Institute of Mathematics, Academia Sinica, Taiwan.

 

2.      TBA.

·    Forest Workshop 2024 (March 29–31). TKP Garden City Premium Sapporo Odori, Japan.

 

3.      Mathematical foundation of various MCMC methods.

·    French Japanese Conference on Probability & Interactions (March 6–8). IHES, France.

 

Year 2023

 

1.      Mathematical foundation of various MCMC methods.

·    Mathematics of Random Systems Summer School 2023 (September 11–15). RIMS, Kyoto University, Japan.

 

2.      Stability of the critical behavior of the Ising model against quantum perturbation.

·    Workshop on Probabilistic Methods in Statistical Mechanics of Random Media and Random Fields 2023 (January 9–13). Kyushu University, Japan.

 

Year 2022

 

1.      Stability of the critical behavior of the Ising model against quantum perturbation.

·    Tokyo Probability Seminar (December 26). Keio University, Japan.

 

2.      Stability of the phase transition and critical behavior of the Ising model against quantum perturbation.

·    Probability Symposium (December 19–22). RIMS, Kyoto University, Japan.

 

3.      Spread-out limit of the critical points for various statistical-mechanics models.

·    Probability and Analysis on Random Structures and Related Topics (August 8–10). RIMS, Kyoto University, Japan.

 

4.      Mixing time and simulated annealing for the stochastic cellular automata, and beyond.

·    Workshop on Probabilistic Methods in Statistical Mechanics of Random Media and Random Fields 2022 (January 11–14). Kyushu University, Japan.

 

Year 2021

 

1.      Mixing time and simulated annealing for the stochastic cellular automata, and beyond.

·    The Annual Probability Symposium (December 14–17). Kyoto University, Japan.

 

2.      Stochastic optimization via parallel dynamics: rigorous  results and simulations.

·    The 53rd ISCIE International Symposium on Stochastic Systems Theory and Its Applications (October 30–31). Ritsumeikan University, Japan.

 

Previous years

 

 

                  IV.       Organizing scientific meetings

 

Year 2024

 

·        The Japanese-German Open Conference on Stochastic Analysis 2024 (September 913, 2024). Hokkaido University, Japan.

 

·        Hokkaido Math-Sci Seminar (February 14, 2024). Hokkaido University, Japan.

 

Year 2023

 

·        The IMS Program gRandom Interacting Systems, Scaling Limits, and Universalityh (December 422, 2023). IMS, National University of Singapore, Singapore.

 

·        The 16th HU-SNU Joint Symposium on Mathematics (November 11, 2023). Hokkaido University, Japan.

 

·        One-day Workshop on Mathematical Analysis (July 11, 2023). Hokkaido University, Japan.

 

Year 2022 & before

 

·        ”—˜AŒg„iŽΊƒCƒxƒ“ƒguŽΠ‰ο‚ōvŒ£‚·‚鐔Šwv (December 2, 2022). Hokkaido University, Japan.

 

·        The RIMS Workshop gRigorous Statistical Mechanics and Related Topics IVh (November 1518, 2022). RIMS, Kyoto University, Japan.

 

·        Pacific Workshop on Probability and Statistical Physics (December 911, 2021). PIMS, University of British Columbia, Canada.

 

·        The RIMS Workshop gRigorous Statistical Mechanics and Related Topics IIIh (November 1619, 2021). RIMS, Kyoto University, Japan.

 

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

 

·        The RIMS Workshop gRigorous Statistical Mechanics and Related Topics IIh (November 2427, 2020). RIMS, Kyoto University, Japan.

 

·        The RIMS Workshop gRigorous Statistical Mechanics and Related Topicsh (November 1821, 2019). RIMS, Kyoto University, Japan.

 

·        The 1-day workshop gRecent Progress in Probability Theory and Its Applicationsh (July 28, 2017). Hokkaido University, Japan.

 

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

 

·        The 2nd workshop on Universality and Scaling Limits in Probability and Statistical Mechanics (August 59, 2013). Hokkaido University, Japan.

 

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

 

·        The RIMS workshop gApplications of Renormalization Group Methods in Mathematical Sciencesh (September 1214, 2011). Kyoto University, Japan.

 

·        The SPA Satellite workshop gUniversality and Scaling Limits in Probability and Statistical Mechanicsh (August 30September 3, 2010). Hokkaido University, Japan.

 

 

                     V.        Teaching (April 2023 – February 2024)

 

2nd semester

Monday

Tuesday

Wednesday

Thursday

Friday

8:45 – 10:15

N.A.

N.A.

N.A.

N.A.

‰πΝŠwF

10:30 – 12:00

όŒ`‘㐔Šw‡U

–μ“ci11:00-j

’|“ΰi11:00-j

ˆκ”Κ‹³ˆη‰‰K

’Ή‹i11:00-j

13:00 – 14:30

N.A.

‹ίœAi-14:00j

‘ˆδi-14:00j

N.A.

–μΰVi-14:00j

14:45 – 16:15

όŒ`‘㐔Šw‡U

N.A.

CREST

N.A.

ˆ’“μi-15:10j

16:30 – 18:00

”Šwu“ǁi17:00-j

N.A.

CREST

F.M.

Q-Ising

18:00 – 19:30

”Šwu“ǁi-18:30j

N.A.

O.H.

F.M.

Q-Ising

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

 

1.     Group Seminars @ Science Bldg 4-509 on Tuesdays and Wednesdays, @ Science Bldg 4-506 on Fridays.

·        B4 seminar (ˆ’“μ) on Introduction to Stochastic Integration.

·        B4 seminar (‘ˆδ) on Stochastic Partial Differential Equations.

·        B4 seminar (’|“ΰ) on Intersections of Random Walks.

·        B4 seminar (‹ίœA) on Introduction to a Renormalisation Group Method.

·        M1 seminar (’Ή‹) on The Parabolic Anderson Model.

·        M1 seminar (–μΰV) on The Random-cluster Model.

·        M2 seminar (–μ“c) on Simulated Annealing Alogorithms and Markov Chains with Rare Transitions.

·        SCA/DA meeting (Fukushima-Kimura, ‰Ν–{, –μ“c) @ Science Bldg 3-513.

·        Q-Ising meeting @ zoom.

 

2.     όŒ`‘㐔ŠwI @ Multimedia Education Bldg E-311.

·        Mondays 10:30–12:00

·        Mondays 14:45–16:15

 

3.     ”Šwu“Η Mondays 18:15–19:45 @ Science Bldg 4-509.

 

4.     ˆκ”Κ‹³ˆη‰‰KiƒtƒŒƒbƒVƒ…ƒ}ƒ“ƒZƒ~ƒi[j Thursdays 10:30–12:00 @ Multimedia Education Bldg E-312.

 

5.     ‰πΝŠwF Fridays 8:45–10:15 @ Science Bldg 3-309.

 

1st semester

Monday

Tuesday

Wednesday

Thursday

Friday

8:45 – 10:15

N.A.

‰ΘE‹Z‚½‚Μ‚΅‚έ

N.A.

’Ή‹(8:50`)

–μ“c(9:30`)

10:30 – 12:00

όŒ`‘㐔Šw‡T

N.A.

N.A.

’|“ΰ(10:00`)

ˆ’“μ(10:40`)

13:00 – 14:30

N.A.

N.A.

όŒ`‘㐔Šw‡T

‹ίœA(11:10`)

–μΰV(13:30`)

14:45 – 16:15

όŒ`‘㐔Šw‡T

N.A.

N.A.

F.M.

‘ˆδ(14:40`)

16:30 – 18:00

N.A.

Q-Ising

SCA/DA

F.M.

‰Ν–{

18:00 – 19:30

CREST

N.A.

O.H.

F.M.

N.A.

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

 

6.     Group Seminars @ Science Bldg 3-413.

·        B4 seminar (ˆ’“μ) on Introduction to Stochastic Integration.

·        B4 seminar (‘ˆδ) on Introduction to Stochastic Processes.

·        B4 seminar (’|“ΰ) on Intersections of Random Walks.

·        B4 seminar (‹ίœA) on Theory of Probability and Random Processes.

·        M1 seminar (’Ή‹) on The Parabolic Anderson Model.

·        M1 seminar (–μΰV) on The Random-cluster Model.

·        M2 seminar (–μ“c) on Statistical Mechanics of Lattice Systems.

·        D3 seminar (‰Ν–{) on the Lace Expansion @ Science Bldg 3-513.

·        SCA/DA meeting (Fukushima-Kimura, ‰Ν–{, –μ“c) @ Science Bldg 3-513.

·        CREST meeting (Ž›–{, Fukushima-Kimura, ‰Ν–{, –μ“c) @ Science Bldg 3-513.

·        Q-Ising meeting (γ“‡) @ zoom.

 

7.     όŒ`‘㐔ŠwI @ Multimedia Education Bldg E311.

·        Mondays 10:30–12:00

·        Mondays 14:45–16:15

·        Wednesdays 13:00–14:30

 

8.     ‰ΘŠwE‹Zp‚̐’ŠEF”Šw‚Μ‚½‚Μ‚΅‚έ Tuesdays 8:45–10:15 @ Multimedia Education Bldg E216.

 

 

                  VI.       Curriculum vitae

 

·    February 2020 – present

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

Ø  Vice head of the Department (April 2023 – present)

Ø  Department head of the Academic Affairs Committee (April 2022 – March 2023)

 

·    March 2020 – present

Associate editor of Mathematical Physics, Analysis and Geometry.

 

·    Excellent Teachers 2022, 2021, 2018, 2015, 2012, 2011

The Hokkaido University Presidentfs Award for Teaching Excellence in 2013 and in 2012.

 

·    August 2020 – October 2023

Associate editor of Taiwanese Journal of Mathematics.

 

·    September 2015 – August 2019

Councilor of the Bernoulli Society.

 

·    April 2011 – January 2020

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

 

·    March 2008 – March 2011

Tenure-track assistant professor of L-Station, 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 gAnalyses of the Critical Behavior for the Contact Process based on a Percolation Structureh supervised by Takashi Hara.

 

·    April 1994 – March 1996

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

Awarded M.Sc. for the thesis gApproach to Fractal Growth Phenomenah supervised by Takashi Hara.

 

·    April 1990 – March 1994

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

Awarded B.Sc. for the thesis gRecurrent in the Plane, Transient in Spaceh supervised by Kohei Uchiyama.