Wave–particle interactions in a resonant system of photons and ion-solvated water

Abstract

We investigate a laser model for a resonant system of photons and ion cluster-solvated rotating water molecules in which ions in the cluster are identical and have very low, non-relativistic velocities and direction of motion parallel to a static electric field induced in a single direction. This model combines Dicke superradiation with wave-particle interaction. As the result, we find that the equations of motion of the system are expressed in terms of a conventional free electron laser system. This result leads to a mechanism for dynamical coherence, induced by collective instability in the wave-particle interaction.The mechanisms behind coherence in physical systems are mainly classified into two types. In the first type, coherence is due to long-range order; in the second type, it is due to the collective instability in a many-body system with a long-range interaction. In laser physics, Dicke superradiation belongs to the first type and the free electron laser (FEL) belongs to the second type [1][2][3][4][5]. In this Letter, we present a new laser model that incorporates both types of dynamical coherence mechanism from the aspect of wave-particle interactions [6][7][8][9][10]. The ingredients of this system are photons, solvated ions and water molecules.In Ref.[11] the many-body system of electric dipoles of water molecules that interact with the electromagnetic field radiated from rotating water molecules was studied using a quantum field theoretical approach based on an analogy to an FEL [3,4,[7][8][9][10]12]. In simplified settings, it was shown that, around an impurity that carries a sizeable electric dipole and induces a static electric field oriented in the z-direction, a permanent electric polarization of water molecules in the z-direction emerges in the limit cycle of the system, due to the coherent and collective interaction of the water molecules with the selected modes of the radiation field.Using this result, in this Letter we consider an FEL-like model for a cluster of solvated identical ions with very low, non-relativistic velocities and a uniform direction of motion. The electric dipoles of the water molecules which solvate each moving ion behave as XY spins which interact directly only with the transverse electromagnetic field radiated from the rotating water molecules. On the particle side of the wave-particle (i.e., radiation field-particle) interactions, there are two kinds of elements: water molecules and ions around which the water molecules are trapped by a Lennard-Jones potential.In the FEL model [3][4][5]7], each relativistic unbound electron has the phase degree of freedom of its XY spinlike direction on the x-y plane orthogonal to its direction of motion (called the z-direction). Due to the presence of * konishi.eiji.27c@st.kyoto-u.ac.jp an undulator, that is, a transverse magnetic field created by a periodic arrangement of magnets with alternating poles, the unbound electrons are accelerated, producing synchrotron radiation.In our case, the variable corresponding to the phase coord...

Mechanism for Coherence in the Resonant System of Ion-solvated Water Molecules and Radiation

“…(41) according to Ref. [14]. First, note that the angle of rotation of ( e 1 , e 2 ) on the plane orthogonal to e 3 can be chosen arbitrarily by adjusting the phase associated with the energy eigenstates |g and |e of each water molecule (see Eq.…”

“…In this paper, we present a comprehensive exposition of a new spontaneous laser model that was proposed previously in shorter reports by the author [13,14] and incorporates both types of mechanism for coherence of radiation from the aspect of wave-particle interactions [15].…”