arXiv subjects
Publications and source records attributed to S. E. Spence.
The modular valued operator $\widehat{V}_m$ of the von Neumann interaction operator for a projector is defined. The properties of $\widehat{V}_m$ are discussed and contrasted with those of the standard modular value of a projector. The associated notion of a faux qubit is introduced and its possible utility in quantum computation is noted. An experimental implementation of $\widehat{V}_m$ is also highlighted.
The quantum theoretical concepts of modular momentum and dynamical non-locality, which were introduced four decades ago, have recently been used to explain single particle quantum interference phenomena. Although the non-local exchange of modular momentum associated with such phenomena cannot be directly observed, it has been suggested that effects induced by this exchange can be measured experimentally using weak measurements of pre- and post-selected ensembles of particles. This paper reports on such an optical experiment that yielded measured weak values that were consistent with the theoretical prediction of an effect induced by a non-local exchange of modular momentum.
A generalized analytical tripartite loss model is posited for Mach-Zehnder interferometer (MZI) phase sensitivity which is valid for both arbitrary photon input states and arbitrary system environmental states. This model is shown to subsume the phase sensitivity models for the lossless MZI and the ground state MZI. It can be employed to develop specialized models useful for estimating phase sensitivities, as well as for performing associated design trade-off analyses, for MZIs which operate in environmental regimes that are not contained within the ground state MZI's envelope of validity. As a simple illustration of its utility, the model is used to develop phase sensitivity expessions for an MZI with "excited" internal arms and an MZI with "excited" output channels. These expressions yield a conditional relationship between the expected number of photons entering an MZI and its efficiency parameters which-when satisfied-predicts an enhanced phase sensitivity for the MZI with "excited" output channels relative to that for the MZI with "excited" internal arms.