Wigner-Function Fingerprints of Collective Excitations in Mirror-Terminated Waveguide QED

arXiv:2611.04553v1 Announce Type: new Abstract: We investigate the emission profiles of singly excited collective states and propose a matched-mode witnessing protocol in a mirror-terminated waveguide quantum electrodynamics system. The amplitudes and relative phases of the initial collective excitation are encoded in the temporal mode of the emitted single-photon wavepacket, providing a route to state verification through the common waveguide output. We identify the emission mode associated with a chosen target state and employ an auxiliary virtual-cavity representation to evaluate the quantum state of this selected output mode.