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Field Theory Research Team
Field Theory Research Team
Japanese
Team Leader Yasumichi Aoki
yasumichi.aoki[at]riken.jp (Lab location: Kobe)
- Please change [at] to @
- 2018
- Team Leader, Field Theory Research Team (-present)
- 2016
- Associate Professor, Theory Center, High Energy Accelerator Research Organization (KEK) (-present)
- 2016
- Fellow, RIKEN BNL Research Center
- 2016
- Researcher, KEK Theory Center
- 2010
- Associate Professor, Center for Theoretical Studies, Nagoya University
- 2006
- Fellow, RIKEN BNL Research Center
- 2003
- Researcher, Physics Department, University of Wuppertal
- 2003
- Postdoctoral Fellow, Department of Physics, Columbia University
- 2000
- Research Associate, RIKEN BNL Research Center
- 1997
- Research Associate, Institute of Physics, University of Tsukuba
- 1997
- PhD, University of Tsukuba
- 1996
- COE Researcher, Center for Computational Physics, University of Tsukuba
- 1996
- Graduate School of Physics, University of Tsukuba completed without degree
Keyword
- Theory of Elementary Particles
- Lattice Gauge Theory
- Large Scale Numerical Computations
Research summary
Inferring theoretical predictions from the Standard Model (SM) of elementary particles, which explains most of the existing experimental and observational results of particle physics, often include the predictions of the behavior of particle systems in extreme conditions such as high temperature and/or density, and precision tests of the SM using hadronic reactions as well as investigation of physics beyond the SM.
Numerical simulations with lattice QCD techniques using a realistic set of parameters are becoming feasible. However, many significant questions remain unsolved, which we are addressing by employing lattice methods while preserving as many important symmetries as possible-the symmetries often sacrificed to make the simulations less demanding. In order to use supercomputer Fugaku for such demanding computations, we will develop algorithms, analysis methods, and codes, while performing computation on existing HPC resources. In the first principle computations of the models, we aim to bridge the energy scale layers, and thereby reveal the nature of the evolution of the universe and the mechanism of matter creation in it.
Main research results
Novel behavior of two-flavor QCD near phase transition
Phase structure of the two-flavor QCD, a model of real world QCD, which has actually three active dynamical quark flavors, is largely unexplained, including the order of phase transition. We are investigating the properties of phase transition employing a chirally invariant formulation of QCD on the lattice. The figure (from JLQCD collaboration) indicates a phase transition at around m=10 MeV and a temperature of T=220 MeV, which is surprisingly higher than the m=0 transition temperature of T=175 MeV. Follow-up study using the Oakforest-PACS is underway by varying the system size to infer results at the thermodynamic limit of the model. Codes for these studies as well as for supercomputer Fugaku is being developed in parallel with the computation, the aim being not only to investigate two-flavor thermodynamics, but also to perform general QCD simulations with three and more flavors.

Representative papers
- Izubuchi, T, Kuramashi, Y, Lehner, C., and Shintani, E.:
"Finite-volume correction on the hadronic vacuum polarization contribution to muon g-2 in lattice QCD"
Phys. Rev. D 98, 054505, 1-13. (2018). - Kadoh, D., Kuramashi, Y., Nakamura, Y., Sakai, R., Takeda, S., and Yoshimura, Y.:
"Tensor network formulation for two-dimensional lattice N=1 Wess-Zumino model"
J. High Energ. Phys. 03, 141 (2018). - Aoki, Y., Izubuchi, T., Shintani, E., and Soni, A.:
"Improved lattice computation of proton decay matrix elements"
Phys. Rev. D 96, 014506, 1-17. (2017). - Aoki, Y., et al.: (LatKMI Collaboration)
"Light flavor-singlet scalars and walking signals in Nf = 8 QCD on the lattice"
Phys. Rev. D 96, 014508-1–57. (2017). - Chambers, A. J., Dragos, J., Horsley, R., Nakamura, Y. et al.:
"Electromagnetic form factors at large momenta from lattice QCD"
Phys. Rev. D 96, 114509 (2017). - Jin, X.-Y., Kuramashi, Y., Nakamura, Y., Takeda, S., and Ukawa, A.:
"Critical point phase transition for finite temperature 3-flavor QCD with nonperturbatively O(a) improved Wilson fermions at Nt =10"
Phys. Rev. D 96, 034523 (2017). - Aoki, Y., Ishikawa, T., Izubuchi, T., Lehner, C., and Soni, A.:
"Neutral B meson mixings and B meson decay constants with static heavy and domain-wall light quarks"
Phys. Rev. D 91, 114505-1-34. (2015). - Aoki, Y., et al.: (LatKMI Collaboration).
"Light composite scalar in twelve-flavor QCD on the lattice"
Phys. Rev. Lett. 111, 162001. (2013). - Aoki. Y., et al.: (RBC and UKQCD Collaborations).
"Continuum Limit Physics from 2+1 Flavor Domain Wall QCD"
Phys. Rev. D 83, 074508-1-72. (2011). - Aoki, Y., Endrodi, G., Fodor, Z., Katz, S., Krieg, S., and Szabo, K.:
"The order of the quantum chromodynamics transition predicted by the standard model of particle physics"
Nature 443, 675-678. (2006).