Fig. 2: Two components \(\left\vert \widetilde{\psi }\right\rangle\) and \(\left\vert \psi \right\rangle\), of two-particle wavefunctions, shown in the schematics of Fig. 1B.
From: Measuring statistics-induced entanglement entropy with a Hong–Ou–Mandel interferometer
A Pre-collision configurations. Two particles (red and blue pulses) are injected from \({{{{{{{{\mathcal{S}}}}}}}}}_{A}\) and \({{{{{{{{\mathcal{S}}}}}}}}}_{B}\), respectively. Hereafter, post-scattering quasi-particles comprise contributions from both incident particles (blue and red). B, C Constituents of the state \(\left\vert \tilde{\psi }\right\rangle\)\(\,=\,\left\vert {\psi }_{2,0}\right\rangle\,+\,\left\vert {\psi }_{0,2}\right\rangle\). D, E Constituents of the Bell pair state \(\left\vert \psi \right\rangle\)\(\,=\,\alpha \left\vert {\uparrow }_{A}\right\rangle \left\vert {\uparrow }_{B}\right\rangle\,+\,\beta \left\vert {\downarrow }_{A}\right\rangle \left\vert {\downarrow }_{B}\right\rangle\), Eq. (6). In comparison to \(\left\vert \tilde{\psi }\right\rangle\) configurations, particle states of \(\left\vert \psi \right\rangle\) configurations are entangled, both within (indicated by dashed ellipses) and between (indicated by the red–blue mixed pulses) subsystems.
