Quantum technology encompasses computing, communication, imaging and sensors. The last of the four, quantum sensors, are providing qualitatively new data about our world, which can be turned into valuable information about our environment. This will underpin advances in everything from autonomous transport, navigation and brain imaging to the Internet of Things.

The University of Birmingham leads an £80 million consortium, the UK Quantum Technology Hub for Sensors and Metrology, which exploits quantum effects to build next-generation sensors for gravity, magnetic fields, rotation, time, THz radiation and quantum light. 

Part of a £270 million government investment plan, the hub is moving from laboratory and prototypes thanks to industry collaboration, with a second phase of funding just announced.  Scientific progress so far reveals diverse use cases, from mapping the underworld to improving infrastructure safety, to innovative magnetic imaging for dementia.

Mapping the underworld

We know more about Antarctica than what lies a mere few metres below our ground surface in some urban areas including utility infrastructure (such as pipes, cables, sewers), transport infrastructure (tunnels) and deeper down, mine-shafts, old foundations, and emerging sinkholes. These pose geotechnical risks for infrastructure and brownfield developments. Millions of pounds are spent on site investigations for projects like HS2 rail, and huge delays and additional costs are incurred in excavation and during additional roadworks that result from now knowing what lies beneath our feet. The utility industry undertakes 1.5 million streetworks annually to repair, maintain and upgrade its vast network of buried infrastructure.

The delays and overspend that bedevil public works are often caused by what’s under the surface. One Netherlands-based study linked 37% of construction delays to ground condition problems . Buried assets like electricity cables and gas pipes are a health and safety threat too if they are accidentally damaged. The global construction sector, linked to 13% of global GDP, is a productivity sluggard, with a 1% annual productivity increase over the last 20 years. Too little innovation has come to the sector. 

Conventional imaging relies on radio frequency electromagnetic sensors such as Ground Penetrating Radar (GPR), but soil attenuates the signal and can stop it reaching more than a few centimetres into the ground, but buried assets like pipes, electric and telecoms cables can be up to just over a metre deep. Quantum technology gravity sensors, in contrast, can detect much further - and theoretically, all the way to centre of the earth as they are measuring a passive field and are not sending an active signal through the ground.  By dropping charged atom clouds which, because of the principle of superposition, can be in two different states at once, it is possible to measure density variations by comparing differences in the ways that atom clouds fall and thus deduce underground conditions. 

The implications go beyond infrastructure - quantum gravity sensors could also guide environmental work like carbon sequestration, spot threats like magma flows, and uncover new minerals and water resources. They could also, by tracing gravitational dynamics of the earth, support navigation in autonomous ships, and underwater vessels with limited access to satellite navigation and radio.

The full resolution brain

Quantum sensors can also be turned inwards, to the brain itself. Our current imaging tools are the equivalent of a black and white camera.  The brain’s functional complexity – it is a rapidly communicating, evolving network, rather than an engine made of discrete parts – combined with its encasement in bone, make it extraordinarily hard to image non-invasively.  Intracranial fluid, because it is electricity-conductive, washes out the signal of electroencephalograms (EEG), a common imaging technology. This is a particular problem when diagnosing and understanding disorders like dementia, which involve deep-brain structures.  

Quantum sensors are supporting the development of magnetoencephalography – the measurement of magnetic fields generated by the flow of current through neuronal assemblies in the brain - revealing how the brain forms and dissolves networks of neurons, on a millisecond timescale, as part of the processes supporting cognition. With quantum sensors,  this can even be done while the subject is moving, unlike current tools. Eventually, such innovations could support the diagnosis and monitoring of other conditions like attention-deficit-hyperactivity disorder and even enable mind-directed game-playing. International funding for brain imaging , from the Obama-era BRAIN initiative to China’s brain-data investments , and growing investment in brain-comptuter interfaces from entrepreneurs including the likes of Elon Musk, all show the growing attention of governments and scientists to the least understood realm of human biology. Revealing its workings, and upgrading its capacities, will be central narratives in 21st century science as brain-related degeneration becomes a bigger public health burden, and as robotics and AI acquire greater cognitive powers. 

Quantum clocks: navigation and timekeeping resilience 

Communication within the information economy relies on three pillars – computer networks, broadcasting and telecommunications. All depend on accurate, synchronised time over a geographically distributed network, and often dependent on global navigation satellite systems (GNSS). Precision timing and positioning underpins everything from smartphones to high-speed financing trading. Atomic clocks are how satellites keep time, which is done by measuring the microwave frequency needed to make electrons jump from lower to higher orbits as they absorb and lose energy. Atomic clocks have actually been one of the first quantum technologies entering the real economy. Quantum technology now offers the potential to move to optical clocks, which replace the microwave with a laser, leading to a massively better precision.

Quantum clocks could provide crucial resilience mechanism in a world overly reliant on GNSS networks, which faces multiple threats, from malicious attacks like jamming, spoofing or state aggression, to rare but real perils like solar flares and space weather. Data suggests the economic impact of a UK GNSS disruption could be as much as £5.2 billion over a five day period, including on emergency services, road logistics and the maritime industry .

Securing the UK’s quantum advantage 

Quantum sensors could support both political and commercial priorities in the UK. Lynchpin infrastructures like HS2, brownfield building to solve the housing crisis, and the upkeep of our crucial utilities and transport infrastructure, would be made safer, cheaper and faster if we know more about what lies beneath. Next-generation brain imaging will help us respond to public health threats like dementia; 850,000 people already live with it, at a cost of £23 billion per year, forecast to triple by 2040, higher than cancer, heart disease and stroke . And quantum-enhanced atomic clocks could support our precision time-dependent industries, like financial services, and bring resilience to a satellite data network that is not invulnerable to profoundly disruptive threats. 

Following the recently accounted UK government funding renewal, a second chapter in quantum research will now quicken technology transfer, support larger field trials, and enable the bringing together of users and system developers. This will help ensure quantum sensors play a key role in the transformation of our knowledge economy, putting quantum innovation at the heart of UK science and securing our global leadership in one of the most exciting frontiers of the 21st century.