4 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…
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…