Coherent control of polarization-dependent spatio-temporal solitons in chiral quantum-dot nanostructures

We theoretically investigate the coherent control of polarization-dependent spatio-temporal solitons in chiral quantum-dot nanostructures. The system is modeled as a four-level chiral quantum dot medium, incorporating interdot tunneling, magnetic excitation, and coherent interactions driven by optical probe and control fields, with the Hamiltonian treated under the dipole and rotating-wave approximations. Quantum interference, governed by the relative phase of the control field and the tunneling strength, enables dynamic tuning of the complex refractive index for right- and left-circularly polarized beams. Both dispersion and absorption are sensitively modulated by the chiral coupling, allowing the medium to support diverse self-sustained nonlinear excitations, including bright, dark, and periodic spatio-temporal solitons. The soliton dynamics, analyzed as functions of normalized propagation distance and time, show that enhanced tunneling reshapes soliton velocity, temporal width, and spatial confinement while preserving chiral asymmetry. These results highlight the interaction of tunneling-modified electronic states, field-induced coherence, and polarization-selective effects, demonstrating the potential of chiral quantum-dot nanostructures for polarization-controlled photonic devices and soliton-based optical information processing.