Past of a Quantum particle: An atom interferometric based study

The past of a Quantum particle and the investigations of the particle's unitary evolution in between two strong measurements have generated a heated debate recently in quantum foundational context mainly studied earlier through photonics techniques. We, however, here propose an atom interferometric exploration based on the time tested tools of Atomic Bragg Diffraction to study the past of an atom, more akin to a real, concrete particle as compared with its counterpart i.e. photon. Two-State Vector Formalism (TSVF) along with the methodology of weak measurement have been invoked for the analysis of the past of an atom traversing a Mach-Zehnder Bragg atom interferometer and the results obtained are quite interesting. It is also being demonstrated explicitly that the suggested schematics are inherently deterministic and the proposal can be experimentally executed with high enough fidelity under the prevailing atom-field interaction based laboratory tools.