title: Hydrogen-bond memory and water-skin supersolidity resolving the Mpemba paradox.
abstract: The Mpemba paradox, that is, hotter water freezes faster than colder water, has baffled thinkers like Francis Bacon, René Descartes, and Aristotle since B.C. 350. However, a commonly accepted understanding or theoretical reproduction of this effect remains challenging. Numerical reproduction of observations, shown herewith, confirms that water skin supersolidity [Zhang et al., Phys. Chem. Chem. Phys., DOI: ] enhances the local thermal diffusivity favoring heat flowing outwardly in the liquid path. Analysis of experimental database reveals that the hydrogen bond (O:H-O) possesses memory to emit energy at a rate depending on its initial storage. Unlike other usual materials that lengthen and soften all bonds when they absorb thermal energy, water performs abnormally under heating to lengthen the O:H nonbond and shorten the H-O covalent bond through inter-oxygen Coulomb coupling [Sun et al., J. Phys. Chem. Lett., 2013, 4, 3238]. Cooling does the opposite to release energy, like releasing a coupled pair of bungees, at a rate of history dependence. Being sensitive to the source volume, skin radiation, and the drain temperature, the Mpemba effect proceeds only in the strictly non-adiabatic 'source-path-drain' cycling system for the heat "emission-conduction-dissipation" dynamics with a relaxation time that drops exponentially with the rise of the initial temperature of the liquid source.
authors.affiliation: NOVITAS, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798. ecqsun@ntu.edu.sg.
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.forename: Yongli
authors.initials: Y
authors.lastname: Huang
authors.forename: Zengsheng
authors.initials: Z
authors.lastname: Ma
authors.forename: Yichun
authors.initials: Y
authors.lastname: Zhou
authors.forename: Ji
authors.initials: J
authors.lastname: Zhou
authors.forename: Weitao
authors.initials: W
authors.lastname: Zheng
authors.forename: Qing
authors.initials: Q
authors.lastname: Jiang
authors.forename: Chang Q
authors.initials: CQ
authors.lastname: Sun