This article describes the basic concepts of artificial intelligence (AI) and discusses the relationship between physical and AI literature. First, the author introduces the brief history of artificial intelligence research on the first era in 1950-th, the second era in 1980-th, and the third-era, currently developing. Second, he explains basic concepts of AI from epistemological, ontological, evolutional, and agent society view points. Third, the agent-based modeling approach is introduced with results of his recent reports. Forth, the differences of physical and artificial sciences are discussed. The article concludes that the emergence of new scientific disciplines comes from the interaction of boundary of existing fields, thus, the relationship between physical sciens and AI will play important roles in the future.
Current cosmological observations are so precise that now we have a lot of information on the inflationary Universe. However, we are still far from complete understanding of the actual mechanism of how the inflation is realized and primordial fluctuations are generated. In this article, first we briefly review the basics of the inflationary cosmology and summarize its current status from the viewpoint of observational results such as those from Planck satellite. Then we discuss to what extent we can understand the inflationary Universe from future observations of power spectrum and non-Gaussianity of primordial fluctuations as well as gravitational waves. Their implications on inflationary models are also discussed.
Searching the target plays an important role in life. DNA binding proteins can trigger the protein level and edit DNA in the living cell. These proteins need to search for the target sequence of DNA from a very long DNA sequence for initiating their functions. This is the so called target search problem of DNA binding proteins. In this study, we used single molecule fluorescence microscopy to understand how DNA binding protein p53 solves the target search problem.
Fast radio bursts (FRBs) are enigmatic radio transients with large dispersion measure. There are 30 of FRBs discovered so far and only one of them, FRB 121102, repeats. Recently, the host galaxy and persistent radio counterpart have identified for this repeating FRB. First, we overview the observational results and the general implications. Then, we focus on the young neutron star model for FRBs. In particular, we discuss the possible connection between FRBs and energetic supernovae.
A quantum spin liquid (QSL) is an exotic state of matter in condensed-matter systems, where the electron spins are strongly correlated, but conventional magnetic orders are suppressed down to zero temperature because of strong quantum fluctuations. One of the most prominent features of a QSL is the presence of fractionalized spin excitations, called spinons. Despite extensive studies, the nature of the spinons is still highly controversial. Here we show quantum-critical scaling of magnetic susceptibility, and spin-lattice decoupling phenomena in the QSL state of an organic triangular-lattice magnet, κ-(BEDT-TTF)2 Cu2(CN)3 . The decoupling phenomena can explain seeming discrepancy between gapped and gapless features of spin excitations in the QSL state. The critical exponent obtained by the scaling greatly constrains the theoretical models for the QSL, and at present, there is no theory to explain the values, to the best of our knowledge.