Special Winter Seminar Series - Quantum Computing and Information
Qubit sensors in correlated quantum noise environments:
From noisy quantum metrology to quantum noise spectroscopy
Lorenza Viola – Dartmouth College
Qubit systems offer unique opportunities for sensing and estimation. On the one hand, the use of entangled qubit states can yield measurement precision that exceeds the optimal bounds achievable classically. On the other hand, the exquisite sensitivity of qubits to their surrounding environment makes them natural spectrometers of their own noise. In this talk, I will present recent results on both parameter estimation and spectral estimation by qubit sensors in realistic correlated noise environments. I will first consider the paradigmatic setting of frequency estimation by Ramsey interferometry and show how spatiotemporally correlated quantum noise can introduce additional sources of uncertainty due to uncontrolled entanglement of the qubit sensors mediated by the bath. I will then highlight some of our efforts toward developing control methods for quantum noise spectroscopy. In particular, I will describe how protocols inspired by spin-locking relaxometry may be used to achieve spectral characterization of correlated noise in a two-qubit system, and outline a recent experiment using a superconducting qubit device.
All interested persons are invited to attend remotely—email physics@nd.edu for information.
Originally published at physics.nd.edu.