24 citations · 156 across the 27 of their papers we have counts for
27 papers
Pink Noise in Economic Time Series from Synchronization and Amplitude Demodulation
Masahiro Morikawa, Yokoh Morikawa, Akika Nakamichi
Pink noise, characterized by a power spectral density with , appears in economic indices as well as in many natural systems. We summarize a unified mes…
A Synchronized Spin Model for Black-Hole Accretion Systems
Masahiro Morikawa, Akika Nakamichi
Black-hole accretion systems exhibit a characteristic coexistence of activities: broad-band X-ray variability, hot coronae, wide-angle winds, and both steady and discrete jets. Thi…
Pink noise in Electric Current from Amplitude Modulations
Masahiro Morikawa, Akika Nakamichi
We recently proposed that the general origin of 1/f fluctuation, or pink noise, is the amplitude modulation (or beat) of many waves with accumulating frequencies. In this paper, we…
Dynamic Synchronization and Resonance as a Universal Origin of 1/f Fluctuations -- Amplitude Modulation Across Music and Nature
Akika Nakamichi, Izumi Uesaka, Masahiro Morikawa
We propose a universal physical mechanism for the emergence of 1/f fluctuations, observed across a wide range of systems. In particular, we verify this on acoustic cases. The mecha…
Solar Flare 1/f Fluctuations from Amplitude Modulated Five Minute Oscillation
Masahiro Morikawa, Akika Nakamichi
We first study the solar flare time sequence based on the GOES16 data. We find that the power spectrum density of the low-energy (E\leq E_{mean}) flare shows 1/f fluctuations, but…
Seismic 1/f Fluctuations from Amplitude Modulated Earth's Free Oscillation
Akika Nakamichi, Manaya Matsui, Masahiro Morikawa
We first report that the seismic time-sequence data from around the world, excluding major earthquakes, consistently yield the power spectral density inversely proportional to the…