Detecting and tracking bacteria with quantum light

TL;DR

This paper explores how quantum light can enhance the detection and tracking of bacteria, specifically E. coli and Salmonella, by reducing photon usage and improving early-stage growth monitoring and species discrimination.

Contribution

It demonstrates the potential advantages of quantum sensing in biological measurements, highlighting improved early detection and discrimination capabilities over classical methods.

Findings

Quantum light can track bacterial growth with fewer photons.

Quantum resources outperform classical in early bacterial detection.

Quantum sensing improves early discrimination between bacterial species.

Abstract

The field of quantum sensing aims at improving the detection and estimation of classical parameters that are encoded in physical systems by resorting to quantum sources of light and quantum detection strategies. The same approach can be used to improve the current classical measurements that are performed on biological systems. Here we consider the scenario of two bacteria (E. coli and Salmonella) growing in a Luria Bertani broth and monitored by classical spectrophotometers. Their concentration can be related to the optical transmissivity via the Beer-Lambert-Bouguer's law and their growth curves can be described by means of Gompertz functions. Starting from experimental data points, we extrapolate the growth curves of the two bacteria and we study the theoretical performance that would be achieved with a quantum setup. In particular, we discuss how the bacterial growth can, in principle, be tracked by irradiating the samples with orders of magnitude fewer photons, identifying the clear superiority of quantum light in the early stages of growth. We then show the superiority and the limits of quantum resources in two basic tasks: (i) the early detection of bacterial growth and (ii) the early discrimination between two bacteria species.