IQIM Postdoctoral and Graduate Student Seminar

Joint IQIM/AWS Seminar

Abstract: Quantum metrology leverages quantum effects to improve the precision in estimating an unknown parameter or set of parameters. In studying such problems, we seek to derive tight information theoretic lower bounds on the best possible performance of a measurement task and to provide specific protocols that achieve these bounds. The standard single parameter estimation task, where a single unknown parameter is coupled linearly to a sensor network of d quantum sensors, is well understood in this context and it is known that maximal entanglement is necessary for achieving optimal performance (the so-called Heisenberg limit). In this talk, I will discuss the more complicated problem of optimally measuring a single function of multiple unknown parameters where each sensor in the network is coupled to a unique parameter. Such problems are highly general and encompass a number of interesting and relevant metrological tasks such as field interpolation and noise characterization. I will present information theoretic bounds on the precision with which such functions can be measured and describe how to construct protocols using the smallest possible amount of entanglement to achieve such bounds. I will also consider the case where the unknown parameters are not independent, which further impacts how entanglement can best be leveraged for metrological gain.

Attendees joining in person must demonstrate that they comply with Caltech's vaccination requirements (present Caltech ID or AWS ID or vaccination and booster confirmation).