Research

Dr Cristian Bonato, Heriot Watt University, will be visiting the School of Engineering. As part of his visit he will deliver a seminar entitled, "Adaptive Quantum Sensing with Single Spins". Abstract and biography are given below.

Date & Time: 14:00, Monday, 27th March
Venue: Room 514, Rankine Building

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Abstract

A sensor based on a single spin can be used to map magnetic fields at the ultimate limit in spatial resolution, down to the limit of few nanometers. In the past decade, ground-breaking experiments have demonstrated this concept using individual electronic spins associated to the nitrogen-vacancy (NV) centre in diamond. The NV centre effectively behaves as a single atom trapped in the diamond lattice and its electronic spin can be controlled and measured, up to room temperature, by a combination of optical and radio-frequency pulses.
In this talk, I will provide a general introduction to spin-based quantum technology with nitrogen-vacancy centres in diamond and will address the question of how the sensitivity of a quantum sensor can be enhanced by adaptive techniques. Given a quantum system, what is the best measurement protocol to extract the most information about unknown parameters? Given a sequence of measurements on a single spin, outcomes obtained by earlier measurements within the sequence could be used to optimize the settings for later measurements (adaptive estimation). What kind of advantage can this provide? Is adaptive estimation advantageous also in the presence of noise, decoherence and imperfect measurements? I will present an optimized adaptive protocol for quantum sensing that performs better than the best known non-adaptive protocol, leading to a record sensitivity (Nature Nano 11, 247 - 2016).

Biography

Cristian is Assistant Professor at Heriot Watt University. He studied physics at the University of Padova (“Laurea” degree, 2004 – PhD, 2008). In Padova, he worked with Prof. Paolo Villoresi on experiments leading to the first demonstration of single photon exchange between an orbiting satellite and a ground-based optical station. During his PhD, he spent two years at Boston University, in the lab of Prof. Alexander Sergienko, studying the spatial properties of photonic entangled states. After his PhD, his research interests shifted towards quantum optics in solid-state systems, in particular on the interaction between single spins and photons. He moved to the Netherlands for two post-doctoral positions, one in Leiden with Prof. Dirk Boumeester on cavity quantum electrodynamics with self-assembled quantum dots and one in Delft with Prof. Ronald Hanson on single spins associated with defects in diamond.

First published: 15 March 2017