Gaussian phase sensitivity of boson-sampling-inspired strategies

In this paper we study the phase sensitivity of generic linear interferometric schemes using Gaussian resources and measurements. Our formalism is based on Fisher information. This allows us to separate contributions measurement scheme, experimental imperfections, auxiliary systems. We demonstrate strength a broad class multimode states that includes well-known results from single- two-mode metrology scenarios. Using this, prove input coherent or squeezing improve upon nonclassical proposed in preceding boson-sampling-inspired phase-estimation schemes. also develop polychromatic protocol, demonstrating an enhanced with respect squeezed-vacuum states, for which ideal homodyne detection formally shown be optimal.