While it is not possible to detect the anti-phase coherences generated by the DFHE directly, it is still possible to get a qualitative assessment of the entangling gate by recording the 𝜏 dependence of the in-phase coherences. By incrementing the inter-pulse delay 𝜏, the intensity of the echo generated by the DFHE sequence should oscillate with frequency 𝜔 )* . This experiment is analogous to the 2P-ESEEM experiment (Figure ), and so in addition to the desired inter-electron oscillation the recorded echo intensity will decay due to decoherence and may also be modulated by electron-nuclear couplings. These 'background' effects can be removed by division of a dual-frequency 2P-ESEEM experiment by a comparable single frequency trace, and the result matches well with the inter-electron coupling oscillations recorded by DEER (Figure ). While the recorded oscillations are not direct evidence of the presence of anti-phase coherences, and thus pseudo-entanglement, they do imply that the entangling pulse sequence is working as expected. It follows that with an inter-pulse delay of 125 ns, corresponding to a quarter period of the dipolar evolution, the system will be maximally entangled.