Quantum limited estimation of multiple parameters

5 04/2016

Tuesday, 05 Apr. 2016, 15:00 - 15:45

Workgroup Fuentes Group

Presenter: Animesh Datta; University of Warwick, UK
Host: I. Fuentes
Where: Ernst-Mach-Hörsaal, Boltzmanngasse 5, 2. Stk., 1090 Wien

We present a framework for the quantum-enhanced estimation of multiple parameters. We will address scenarios corresponding to both commuting and non-commuting unitary generators, as well as decoherence parameters such as loss and dephasing. We derive the quantum Fisher information matrix to put a lower bound on the total variance of all the parameters involved. We present the conditions for the attainment of the multi-parameter bound, which is not guaranteed unlike the quantum-limited estimation of single parameters. Our study also reveals that too much quantum entanglement may be detrimental to attaining the Heisenberg scaling in the estimation of unitarily generated parameters.