How Quantum sensing is changing the way we see the world
How quantum sensing is changing the way we see the world
By Tim Bowler Business reporter, BBC News 8 March 2019
Imagine a world where you can find out exactly what lies
under your feet, get advanced warning of volcanic eruptions, look around
corners or into rooms, and detect initial signs of multiple sclerosis.
Welcome to quantum sensing, a technology that could
transform our world.
At their heart, these sensors rely on the often baffling
behaviour of subatomic particles, where the classical assumptions of Newtonian
physics cease to exist.
"Quantum physics is said to be 'spooky', with
particles being in two places at once, but it might be less spooky if you think
of them as waves - and waves can be in several places at once," says Prof
Kai Bongs of Birmingham University.
Prof Bongs' Birmingham team is part of a consortium of
academics and businesses developing quantum gravity sensors or gravimeters that
will be twice as sensitive and 10 times as fast as current equipment.
Quantum tech could
"transform the world in ways we can barely imagine," says Kai Bongs
This project, labelled Gravity Pioneer, could greatly
simplify how engineers and surveyors plan and execute major construction
projects.
Currently, the only way to find out what is underneath
the ground is often to carry out exploratory digging, which is both
time-consuming and expensive.
"Some have said that what lies below one metre under
the streets of London is less well-known than Antarctica," says Prof
Bongs.
This is a major headache for construction companies who
have to carry out surveys that can take days.
"There are thousands of mine shafts in the UK, often
two metres or less across, and if the top of the shaft is five metres or more
below ground then they can't currently be detected," explains George
Tuckwell of engineering services firm RSK, which is leading the Gravity Pioneer
project.
"But the new sensor will be able to see most of
them."
It uses rubidium atoms cooled by lasers to just above
absolute zero (-273C) that are propelled upward in a vacuum and then measured
as they fall back under gravity.
It is so sensitive it can detect the tiny fluctuations in
gravity that result from such relatively small underground structures.
This should help speed up survey times, says engineering
firm Teledyne e2V, which is turning Birmingham's prototype into a commercial
model.
Cheaper sensors
Quantum sensing will also help in monitoring volcanoes.
Glasgow University researchers are working with Italian
volcanologists to place a network of 40 tiny gravimeters on Sicily's Mount
Etna, one of the most active volcanoes in the world. As magma chambers fill up
below ground their gravity readings will change, thus giving advanced warning
of volcanic activity.
Scientists already use an array of instruments - such as
seismometers, ground deformation recorders, gas monitors, infrared cameras and
satellite imagers - to monitor volcanoes.
But a network of cheap and permanent gravimeters is a
potential game changer, giving far more accurate readings of magma movements.
"Essentially, we will for the first time be able to
provide gravity imaging for long time periods," says Prof Giles Hammond at
Glasgow's Institute of Gravitational Research.
Using the current generation of bulky non-quantum
gravimeters means scientists have to go on to the mountain and move them around
- which has risks on an active volcano like Etna.
The team is using micro- and nano-fabrication techniques
to make tiny quantum gravimeters on silicon wafers that are 10 times cheaper
than conventional models.
"Our sensor is a mass on a soft spring, and where
that spring sits with a given mass is dependent on gravity. As gravity changes,
where that spring sits also changes," explains Prof Hammond.
The university is also working on a special 3D type of
lidar that will enable you to look round corners, or "see" into a
room.
Conventional lidar measures the distance to an object by
illuminating it with pulsed laser light and then measuring the reflected
pulses. But quantum technology enables scientists to measure the arrival time
of single photons with very high accuracy, in trillionths of a second.
"In a canyon you'll hear your voice echo back,"
says Prof Daniele Faccio, head of Glasgow University's Extreme Light group.
"You can do the same with light or a laser beam. The
light will bounce off walls - so long as you have the geometry right. Then you
can build a 3D image using this data."
The aim is to develop next-generation lidar for
self-driving cars to give them enhanced awareness - through fog, smoke and over
longer distances.
Glasgow's prototype sensor can already detect moving
people 100m away, even when they're a few metres round a corner.
Health benefits
Our detection of degenerative diseases is also set to
change thanks to quantum sensing.
While technology like MRI [magnetic resonance imaging] is
already in use, quantum sensors are simpler, cheaper and have better
resolution, says Sussex University's Prof Peter Kruger.
"Quantum tech is a lot simpler and cheaper and has
better resolution," says Peter Kruger
"In diseases like multiple sclerosis, the processing
speed of the spinal cord to the brain changes. But existing tools cannot pick
this up," he says.
"New quantum sensors would be able to detect these
changes in the way that MRI sensors can't."
Stealthy detection
Not surprisingly, militaries across the world are also
backing research in to quantum sensing.
Gravimeters in particular offer the potential for
detecting your opponent's submarines, for instance. Gravity may be a weak
force, but you can't shield against it.
So while stealth technology may hide your radar
signature, it won't hide you from a quantum gravity sensor.
Last October, scientists at the US Army's RDECOM Research
Laboratory in Maryland took a significant step forward in quantum sensing.
They used lasers to boost Rydberg atoms (which are much
larger than normal atoms) to unusually high energy levels.
"This greatly increases the atom's sensitivity to
electric fields. We've made a giant compass needle that is much more sensitive
than conventional ones," says Dr Paul Kunz, part of the research team.
Armies will want to detect what electrical devices may be
transmitting or receiving data - in other words, "where the good guys and
the bad guys are," adds Dr Kevin Cox.
Unlike conventional receivers designed to detect signals
over a particular frequency in the electromagnetic spectrum, Rydberg atoms are
sensitive to a wide range of frequencies.
And as they don't absorb energy from the field that they
measure, you can use them to detect signals without your opponents realising.
In short, "quantum technology has the potential to
transform the world in ways we can barely imagine," concludes Birmingham
University's Prof Bongs.
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