Quantum multiparameter estimation method applied to noise squeezed states interferometry

• Grant number: 22/13635-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: April 03, 2023
• End date: March 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Physics
• Principal Investigator: Valery Shchesnovich
• Grantee: Matheus Eiji Ohno Bezerra
• Supervisor: Rafal Demkowicz-Dobrzanski
• Host Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil
• Institution abroad: University of Warsaw, Poland
• Associated to the scholarship: 21/03251-0 - Distinguishability theory and Gaussian Boson Sampling, BP.DR

Abstract

The Boson Sampling (BS) is a scheme that consists of injecting single photons into a linear interferometer with posterior sampling at the output, which represents a problem of high complexity for classical computers. However its experimental realization faces dificulties, among the fact that it is necessary to have a large number of indistinguishable single photons and the generation of exactly a single photon in each desired input mode is experimentally hard. In this way, the so-called Gaussian Boson Sampling (GBS) was proposed, difering from the conventional BS by using Gaussians (e.g. squeezed states) states instead of single photons. However, the effects of photon distinguishability and loss also affect GBS in such a way that they are noise sources that must be considered in a realistic model. The quantum parameter estimation method is a framework that has recently been explored in different quantum computing and metrology problems. This method consists in estimate a parameter that is encoded in a state and some measurements are realized. In the context of photonic interference, the phase estimation is a recurrent objective, including scenarios with noise (specially the photon losses). In contrast to the original BS, the interference in the GBS depends on both the phases of the states and of the interferometer, which indicates a high sensitivity to the phases. Therefore, the quantum parameter estimation can be a useful formalism for this problem, considering the phase as our parameter of interest and the photon distinguishability and losses as the sources of noise. (AU)