A Comprehensive Characterization of the Vacuum Beam Guide and Its Applications

The proposed vacuum beam guide (VBG) represents a transformative advance in quantum channel technology, guaranteeing an ultra-low level of attenuation and a broad transmission linewidth, which offers an unprecedented quantum capacity, exceeding Tera-qubits per second on a continental scale. However, the stability of the VBG in terms of interferometry remains unexamined. To address this gap, we have developed a comprehensive noise budget for sources of phase noise in the VBG, highlighting its capabilities for precision interferometry. This model facilitates a comprehensive characterization of the VBG as a photonic quantum channel, thereby allowing a detailed investigation of its potential. Our theoretical analysis finds no technical or fundamental blockers for a VBG and predicts its expected performance in a wide range of quantum applications.