Experimental verification of liquid-liquid critical point hypothesis from the view point of ‘fluctuations’

Abstract

We have studied liquid-liquid phase transition systems from the view point of ‘fluctuations’. New experimental concept we have recently developed is used to detect ‘fluctuations’. The advantage of the method is the simplicity: just compare the two sound velocities, high-frequency one obtained by inelastic x-ray scattering technique and low-frequency one measured by ultrasonic method. We think it will make a substantial contribution to verify the liquid-liquid critical point hypothesis. In this article, we summarize the history of experimental verification of liquid-liquid critical point hypothesis at first. Then, we show some results of our ‘fluctuations’ measurements and explain the theoretical background of the method. Finally, perspective of the method will be given. We believe it will also play a crucial role to understand glass transition phenomena.