2013/06/30 by Matthias D. Lang, Carlton M. Caves · 1 citation
Physics and Astronomy · #quant-ph #gr-qc
paper · pdf · doi:10.1103/physrevlett.111.173601
published as Phys. Rev. Lett. 111, 173601 (2013) · 8 pages, 1 figure, replaced version with minor corrections
arxiv created 2013/10/28 · arxiv updated 2013/10/30
We consider an interferometer powered by laser light (a coherent state) into one input port and ask the following question: what is the best state to inject into the second input port, given a constraint on the mean number of photons this state can carry, in order to optimize the interferometer's phase sensitivity? This question is the practical question for high-sensitivity interferometry. We answer the question by considering the quantum Cramér-Rao bound for such a setup. The answer is squeezed vacuum.