Online ISSN : 2423-8872
Print ISSN : 0029-0181
ISSN-L : 0029-0181
Volume 77, Issue 10
Displaying 1-16 of 16 articles from this issue
  • Takahiro Nishimichi
    Article type: Interdisciplinary
    2022 Volume 77 Issue 10 Pages 656-665
    Published: October 05, 2022
    Released on J-STAGE: October 05, 2022

    Emulation is a technique that replaces costly simulators with much cheaper statistical models in Bayesian inference problems. We have developed DarkEmulator that predicts basic statistical quantities in the cosmological structure formation. This code is then applied to real data from Subaru Hyper Suprime-Cam as well as Sloan Digital Sky Survey. The combination of these two data sets, the former probes the weak gravitational lensing effect while the latter probes the three dimensional galaxy distribution on large scales, offers a unique opportunity to break the degeneracy between cosmology and galaxy physics. We report competitive bounds on the parameter S8 , the amplitude of the cosmological fluctuations at present. This new methodology would serve as a realistic solution for simulation-based inference, which can reveal unexplored information on small scales where nonlinearity is significant.

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  • Masazumi Honda
    Article type: Researches
    2022 Volume 77 Issue 10 Pages 685-689
    Published: October 05, 2022
    Released on J-STAGE: October 05, 2022

    In recent years, technology around quantum computer sounds growing well. Here, as “users” of quantum computers, we discuss how we can apply this development to numerical simulations of quantum field theories. As quantum computer is suitable for Hamilton formalism rather than Lagrange formalism, we do not have infamous sign problem from the beginning in contrast to the conventional Monte Carlo approach. We show recent results on quantum simulations of the charge-q Schwinger model, which is 1+1-dimensional quantum electrodynamics coupled to an electron with electric charge q. It turns out that our approach enables us to explore interesting phenomena coming from non-small θ-term such as negative string tension behavior in potential between charged heavy particles.

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