  Optimal choice of spin polarization enables electron injection into the
helical edge state at a precise position, despite the uncertainty principle,
permitting access to specific nonlocal Green's functions. We show, within 1D
effective description, that this fact facilitates a direct identification of
odd-frequency pairing through parity measurement (under frequency reversal) of
the nonlocal differential conductance in a setup comprising the Josephson
junction on the helical edge state of a 2D topological insulator with two
spin-polarized probes tunnel-coupled to the junction region. A 2D numerical
simulation has also been conducted to confirm theoretical predictions as well
as to demonstrate the experimental feasibility of the proposal.
