• Quantum enhanced estimation of diffusion

      Branford, Dominic; Gagatsos, Christos N.; Grover, Jai; Hickey, Alexander J.; Datta, Animesh; Univ Arizona, Coll Opt Sci (PHYSICAL REVIEW A, 2019-08-30)
      Momentum diffusion is a possible mechanism for driving macroscopic quantum systems towards classical behaviour. Experimental tests of this hypothesis rely on a precise estimation of the strength of this diffusion. We show that quantum-mechanical squeezing can offer significant improvements, which can be attained by general homodyne measurements including position measurement. With 10 dB of squeezing, experiments would require a tenth of proposed free-fall times. Quantum measurements---beyond study of position---could also allow for a more precise estimation. Our results suggest the potential for quantum enhanced estimation of heating and diffusive dynamics more generally.