Quantum Phase Properties of Photon Added and Subtracted Displaced Fock States

• Published in: Annalen der Physik 2019-11, Vol.531 (11), p.n/a
• Main Authors: Malpani, Priya, Thapliyal, Kishore, Alam, Nasir, Pathak, Anirban, Narayanan, Venkatakrishnan, Banerjee, Subhashish
• Format: Article
• Language: English
• Subjects: Displacement; Fock state; Mathematical analysis; nonclassicality; Parameters; Phase distribution; Photons; Properties (attributes); quantum phase; quantum phase sensing; quantum state engineering; Subtraction; Variation
• ISSN: 0003-3804; 1521-3889
• DOI: 10.1002/andp.201900141

Quantum phase properties of photon added and subtracted displaced Fock states (and their limiting cases) are investigated from a number of perspectives, and it is shown that the quantum phase properties are dependent on the quantum state engineering operations performed. Specifically, the analytic expressions for quantum phase distributions and angular Q distribution as well as measures of quantum phase fluctuation and phase dispersion are obtained. The uniform phase distribution of the initial Fock states is observed to be transformed by the unitary operation (i.e., displacement operator) into non‐Gaussian shape, except for the initial vacuum state. It is observed that the phase distribution is symmetric with respect to the phase of the displacement parameter and becomes progressively narrower as its amplitude increases. The non‐unitary (photon addition/subtraction) operations make it even narrower in contrast to the Fock parameter, which leads to broadness. The photon subtraction is observed to be a more powerful quantum state engineering tool in comparison to the photon addition. Further, one of the quantum phase fluctuation parameters is found to reveal the existence of antibunching in both the engineered quantum states under consideration. Finally, the relevance of the engineered quantum states in the quantum phase estimation is also discussed. The role of all the quantum state engineering tools, used in generation of photon added or subtracted displaced Fock state, is established in this application‐oriented study focused on quantum phase from various perspectives. Useful insight regarding nonclassicality in the states under consideration is also provided.