Gaussian quantum metrology and space-time probes

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In this thesis we focus on Gaussian quantum metrology in the phase-space formalism and its applications in quantum sensing and the estimation of space-time parameters.

• We derive new formulae for the optimal estimation of multiple parameters encoded into Gaussian states.
• We discuss the discontinuous behavior of the figure of merit - the quantum Fisher information.
• Using derived expressions we devise a practical method of finding optimal probe states for the estimation of Gaussian channels and we illustrate this method on several examples.