6533b851fe1ef96bd12a9743

RESEARCH PRODUCT

One-dimensional quantum-spin—phonon solitons

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description

The quantum dynamics of a compressible harmonic chain of $N$ two-level atoms strongly interacting with the phonons of the lattice is investigated. Two types of mixed excitations are discussed which propagate through the lattice exhibiting solitonic properties. The first type of solitonlike excitation describes the motion of the wall separating two magnetoelastic domains. This transports less energy than the second type of solitonlike excitation which describes the motion of a single spin reversal in the chain. An explicit expression is obtained for the speed of these excitations as a function of an appropriate shape parameter $h$. These results are obtained by approximate self-consistent integration of a system of nonlinear differential equations related to the Heisenberg equations of motion for atomic operators.