Mainz 2026 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

Q: Fachverband Quantenoptik und Photonik

Q 56: Quantum Optics and Control I

Q 56.7: Talk

Thursday, March 5, 2026, 16:15–16:30, P 3

Phase-sensitivity enhancement in Mach-Zehnder interferometer via local Gaussian operations — Taj Kumar, Krishna Mohan Mishra, Aviral Kumar Pandey, Vikas Kumar Prajapati, and •Devendra Kumar Mishra — Department of Physics, Institute of Science, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India

We investigate the role of local Gaussian operations, specifically local displacement operation (LDO) and local squeezing operation (LSO), in enhancing the phase sensitivity of the Mach-Zehnder interferometer (MZI). We considered two scenarios: when these operations are applied in a single arm only and when they are applied in both arms of the MZI. Using coherent and squeezed vacuum states as inputs and homodyne detection, we analyze the phase sensitivity and the quantum Cramér-Rao bound (QCRB) under both ideal and lossy conditions. Our study reveals that both single- and dual-arm LDO schemes offer equivalent improvements in phase sensitivity. However, the single-arm LSO scheme offers improved phase sensitivity that is superior to its dual-arm counterpart as well. In short, the single-arm configuration is found to be more resource-efficient, providing improved phase sensitivity and enhanced robustness against photon losses. These results emphasize the advantages of the Gaussian operations, such as LDO and LSO, as an experimentally feasible approach with a low implementation cost for achieving enhanced phase sensitivity and robustness against photon losses.

Keywords: Mach-Zehnder interferometer; phase sensitivity; Quantum Cramér-Rao bound (QCRB); Gaussian operations