Modular Quantum Sensor Detects Brain Activity

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BRIGHTON, England, June 14, 2021 — University of Sussex researchers have built and demonstrated a modular quantum sensor capable of recording brain signals. According to the researchers, their device is the first use a modular quantum sensor in the brain to detect a signal. The device uses ultrasensitive quantum sensors to pick up almost imperceptible magnetic fields within the brain to detect and map neural activity.

“Our quantum sensor has to be exceptionally sensitive to pick up the magnetic fields in the brain, which are very weak indeed,” said Ph.D. student Thomas Coussens, who built the sensor. “To put it into context, the magnetic field of a brain is a trillion times lower than that of a fridge magnet.”

The quantum magnetic sensor uses an optically pumped magnetometer inside a magnetic shield, itself used to reduce environmental magnetic fields so as to isolate those within the brain. The sensor itself works by putting a vapor into a quantum state, through which it then shines a laser. A photodetector component determines how much light has passed through. How the atomic vapor interacts with the laser light depends on the magnetic field. This is generated by the tiny electric currents in the neuron, even outside the brain, that the sensor ultimately picks up.

“Because our device is so far unique in that it is modular — and we’ve shown the modularity works by connecting two sensors together — we now plan to scale up this project by building more sensors to turn this into an entire brain imaging system,” Coussens said.

In tests, the team applied sensors to a volunteer’s scalp, close to the visual cortex. The volunteer was asked to open and close their eyes at 10- to 20-s intervals, which generated a signal that the device was able to pick up.

“As our sensor works on a modular basis, we will now be able to scale it up to create much more detailed images of the brain or parts of the brain. You can’t do that with the current commercial product available,” said Peter Krüger, an experimental physicist and director of the Sussex Programme for Quantum Research.

The sensor, he believes, is a large step toward further interdisciplinary studies with a variety of researchers, ranging from consciousness scientists and engineers to neuroscientists.

The research is available in preprint on ariXiv ( It is currently awaiting peer review.

Published: June 2021
The term quantum refers to the fundamental unit or discrete amount of a physical quantity involved in interactions at the atomic and subatomic scales. It originates from quantum theory, a branch of physics that emerged in the early 20th century to explain phenomena observed on very small scales, where classical physics fails to provide accurate explanations. In the context of quantum theory, several key concepts are associated with the term quantum: Quantum mechanics: This is the branch of...
A magnetometer is a scientific instrument used to measure the strength and/or direction of a magnetic field. It can detect and quantify the intensity of magnetic fields in its vicinity. Magnetometers are employed in various applications, including geophysics, navigation, archaeology, and space exploration. There are different types of magnetometers, each with its own operating principles. Common types include fluxgate magnetometers, proton precession magnetometers, and magneto-resistive...
A photodetector, also known as a photosensor or photodiode, is a device that detects and converts light into an electrical signal. Photodetectors are widely used in various applications, ranging from simple light sensing to more complex tasks such as imaging and communication. Key features and principles of photodetectors include: Light sensing: The primary function of a photodetector is to sense or detect light. When photons (particles of light) strike the active area of the photodetector,...
Research & TechnologySensors & DetectorsOpticsLasersImagingquantumbrainbrain imagingmagnetometermagnetometrybrain activitymodularmodular quantum brain sensorUniversity of SussexEuropephotodetectorphotodetectors

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