Quantum Enhanced Sensing Using Gaussian Quantum States

Quantum sensing is a major branch of quantum information technology that uses the principles of quantum mechanics to achieve enhanced precision and accuracy for parameter estimation and hypothesis testing problems. This paper presents a Gaussian quantum states-based quantum sensing paradigm. Gaussian quantum states have the advantage of being relatively easy to generate and manipulate in practice, and they can be used for realizing quantum sensors in the near term. Squeezed quantum states which are an example of Gaussian quantum states can improve the estimation accuracy by reducing the quantum shot noise in one of the quadratures. We present two prototypical examples of Gaussian states-based quantum sensing applications, including quadrature estimation and channel transmittance estimation of a lossy bosonic Gaussian channel. We show that improved estimation can be achieved for both problems by using squeezed states compared to classical coherent states.