Quantum fluctuations do not destroy an optical soliton

А. В. Белинский

А. В. Белинский

А. В. Белинский

Atsushi Ikawa, Shoji Yamamoto, Hideo Fukutome

Quantum fluctuations in the one dimensional half filled Hubbard model are investigated with the resonating Hartree-Fock method with the orbital optimization. The optimized Slater determinants include an inhomo-geneous spin density wave and configurations accommodating some neutral soliton pairs. The short and long range spin orders are destroyed by quantum translational and breathing motions of soliton pairs and gapless Gaussian type fluctuations, respectively. Our calculation suggests that the lowest singlet and triplet excitation branches are the translational modes of breathing neutral soliton pairs dressed with the Gaussian type fluctuations.

Dan Liang

In this paper,the time-dependent variational principle(TDVP) is applied to study the one-dimensional Fermi-Pasta-Ulam(FPU) model,and the dynamic equation of particles in the chain is obtained by TDVP.In the semi-quantal study,the considered quantum effect is quantum fluctuation.The Jackiw-Kerman wave function is used for the single particle.The research results show that quantum fluctuation can disperse,blur and even destroy the nonlinear excitation of FPU model,envelope soliton.The effect of quantum fluctuation has the quasi-exponentional relationship with the effective Plank constant.Furthermore,it is found that coupling the effective Plank constant the anharmonic coupling strength has the joint effect on quantum dissipation.The uniquely joint effect may be induced by the unique Hamiltonian of the FPU chain.

Demin Yao

Quantum fluctuations of optical solitons in fibers are discussed on the basis of the exact quantum states in the frame of the quantum nonlinear Schr\"odinger equation. Position and momentum fluctuations as well as quadrature phase fluctuations are calculated, and explicit results are expressed in terms of the intrinsic quantum parameters. Soliton wave-packet spreading and phase-diffusion phenomena are clearly demonstrated, and the corresponding squeezing effects are analyzed. In particular, soliton amplitude squeezing is investigated in an experimental setup of a Mach-Zehnder interferometer containing an optical fiber. Coherent states for quantum solitons are discussed with attention given to their dynamical preservability. Compared with previous linearized approaches, the present study may provide a more fundamental treatment to quantum fluctuations of solitons.