Path–phase duality with intraparticle translational–internal entanglement
Michal Kolář, Tomáš Opatrný, Nir Bar‐Gill, Noam Erez, Gershon Kurizki · New Journal of Physics · 2007
The aim of this paper is to revisit the implications of complementarity when we inject into a Mach Zehnder interferometer particles with internal structure, prepared in special translational–internal entangled (TIE) intraparticle states. This correlation causes the path distinguishability to be interferometric phase-dependent in contrast to the standard case, where distinguishability depends on some external parameters (not interferometric phase). We show that such a TIE state permits us to detect small phase shifts along with almost perfect path distinguishability, beyond the constraints imposed by complementarity on simultaneous which-way and which-phase measurements for cases when distinguishability is uncoupled to interferometric phase.