LMQ-Talk: Squeezed states as optimum probes for quantum metrology

Organizer:
Joachim von Zanthier

Title:
Squeezed states as optimum probes for quantum metrology

Speaker:
Prof. Girish Agarwal, Texas A & M University (TAMU), College Station, TX, USA

Abstract:
It is well known that all measurements are affected by the intrinsic quantum noise of probes used for measurements. It is important to account for this, particularly when all other sources of technical noise are removed. The inevitable noise of probes can be photon number noise or the noise in the quadratures of the probe. The latter is relevant for homodyne measurements. Thus quantum noise of the probe affects the precision in the measurement of various physical parameters like external electric and magnetic fields and is also detrimental for resolution of images. I will discuss quantum probes and special measurement schemes [ SU(1,1)-SU(m) interferometry] that yield optimal “quantum advantage” over standard probes. I would especially focus on the applications of squeezed states of light and matter, which turn out to be the best probes for measurements of electric fields, rotations, magnetic fields, small molecular densities, and for sensing on quantum networks. I would also bring out the great utility of two mode squeezed states in the quantum metrology of open systems.