Butsuri
Online ISSN : 2423-8872
Print ISSN : 0029-0181
ISSN-L : 0029-0181
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Displaying 1-21 of 21 articles from this issue
Preface
Contents
Interdisciplinary
  • Saori Umehara, Sei Yoshida
    Article type: Interdisciplinary
    2022 Volume 77 Issue 8 Pages 514-522
    Published: August 05, 2022
    Released on J-STAGE: August 05, 2022
    JOURNAL RESTRICTED ACCESS

    Almost all substance of the universe is made of “matter”, not “anti-matter”. This is a mystery of “the matter dominated universe”. The leptogenesis scenario is expected as an attractive solution for the mystery of this “matterdominated universe”. One of the key point of the leptogenesis scenario is the lepton number non-conservation that means “anti-particle” and “particle” can convert to each other. “Observation of neutrino-less double beta decay” provides direct evidence of lepton number non-conserving process.

    The first theoretical indication of “neutrino-less double beta decay” is in 1939. It is pointed out by scientist in nuclear physics. And the rate of “neutrino-less double beta decay” is predicted to be rare. Over 80 years since the indication already passed without observation of neutrino-less double beta decay. At the present day, many scientists of nuclear physics, particle physics and astroparticle physics are interested in the neutrino-less double beta decay in the world. Because one of that, in recent years, the sensitivity of the detector system for neutrino-less double beta decay measurement is dramatically improved. The observation of neutrino-less double beta decay might be coming in a few years, or ten years at the latest.

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Researches
  • Takenobu Nakamura, Takahiro Sakaue
    Article type: Researches
    2022 Volume 77 Issue 8 Pages 523-528
    Published: August 05, 2022
    Released on J-STAGE: August 05, 2022
    JOURNAL RESTRICTED ACCESS

    Long polymer chains are subject to topological constraints, which often dictate the physical properties of the system. Here we propose an unambiguous algorithm to characterize topological constraints in polymer systems based on persistent homology, a key mathematical tool to extract robust topological information from large datasets. We apply the method to the dense solution of non-concatenated entangled rings, where the ring-specific topological constraint, called threading, is often invoked in the literature, whose characterization is, however, nontrivial. Our formulation provides a natural definition of the ring’s threading into another, whereby allowing us to analyze the statistics of threading events in the system. The method is not restricted to ring polymers, thus expected to find broader applications for the study of topological constraints in generic polymeric materials.

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  • Yuta Hamada
    Article type: Researches
    2022 Volume 77 Issue 8 Pages 529-534
    Published: August 05, 2022
    Released on J-STAGE: August 05, 2022
    JOURNAL RESTRICTED ACCESS

    The aim of the Swampland program is to identify the constraints of the quantum gravity on the low energy effective field theory coupled to gravity. In this article, after reviewing the basics, first we show that the extremal black hole can satisfy the weak gravity conjecture thanks to the unitarity and causality of the low energy effective field theory. Then, we argue that the brane probe can be used to constrain the possible patterns of the gauge group of low energy theories. Finally, we point out that the many Swampland statements may be more fundamentally a consequence of the finiteness of quantum gravity amplitudes.

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  • Naoyuki Sakumichi, Takamasa Sakai
    Article type: Researches
    2022 Volume 77 Issue 8 Pages 535-540
    Published: August 05, 2022
    Released on J-STAGE: August 05, 2022
    JOURNAL RESTRICTED ACCESS

    When making yogurt from milk, tofu from soymilk, and jelly from gelatin solution, liquid seeps out of the surface (e.g., whey from yogurt). This study has experimentally identified a universal law essentially governing liquid seeping from these soft and wet solids; the scaling function for linear-polymer solutions describes the osmotic pressure throughout such a gelation process involving both the sol and gel states. This scaling function relates to the O (n)-symmetric universal classes, as found in many systems, from the fields of soft/hard condensed-matter physics to high-energy physics. Our results further advance the foundation of polymer physics and provide a new system for demonstrating universality in statistical mechanics.

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  • Shohei Watabe, Rei Sato, Tetsuro Nikuni
    Article type: Researches
    2022 Volume 77 Issue 8 Pages 541-546
    Published: August 05, 2022
    Released on J-STAGE: August 05, 2022
    JOURNAL RESTRICTED ACCESS

    Emergent properties of quantum search and networks have attracted much attention recently. A quantum search is a faster search algorithm than a classical linear search. In real complex networks, we can find not only scale-free or small-world properties but also fractal properties. In this article, we report recent progress on the quantum search on the fractal lattice, especially on scaling exponents in optimal/effective numbers of the oracle call.

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  • Seiya Hayakawa, Hidetoshi Yamaguchi, Toshitaka Kajino
    Article type: Researches
    2022 Volume 77 Issue 8 Pages 547-552
    Published: August 05, 2022
    Released on J-STAGE: August 05, 2022
    JOURNAL RESTRICTED ACCESS

    We determined the 7Be (n, p0)7Li, 7Be (n, p1)7Li* and 7Be (n, α)4He reaction cross sections by means of the Trojan Horse method which covered the big bang nucleosynthesis (BBN) energy range. The present and the previous data were analyzed by a multi-channel R-matrix fit, providing an improved error evaluation of the (n, p0) channel and the first-ever quantification of the (n, p1) contribution. The reaction rate summing both the present (n, p0) and (n, p1) contributions imposes a new constraint on the 7Li abundance in the BBN calculation, which offers a “free 7Li reduction” to further theoretical challenges to the long-standing cosmological lithium problem.

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