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Quantum Sensing - A New Window to the Underground

A laser-cooled cloud of rubidium atoms in one of the University of Birmingham quantum sensors

Speakers: Catherine Siddle and Professor Michael Holynski, University of Birmingham

Have you ever wondered what is beneath your feet? The underground world contains secrets about our history, and also provides a home for many of our critical utilities and resources. While these are essential to our daily lives, we often do not know exactly where they are – making them difficult to repair or replace, leading to holes being dug in the wrong place. This causes congestion and delay on our roads.

While several technologies exist for looking into the ground, their ability to do so typically depends strongly on ground conditions, and can be limited to the near surface. Gravity sensing provides an interesting solution, as the gravitational force exists between any two masses, regardless of how far apart they are. Yet, even that is typically limited by the presence of vibration – which, due to Einstein’s equivalence principle, is indistinguishable from a noise in the gravity signal. This makes measurements slow and often impractical.

This is one of the problems that quantum sensing may provide the solution to. Utilising the quantum superposition principle, we use clouds of super-cooled atoms to make an exceptionally precise measurement of gravity using a laser as a ruler. Through using a single laser ruler to read out two clouds, we overcome vibration – promising fast and practical measurements, and offering a new window into the underground.

In this Christmas lecture, you will hear about the speakers' work in quantum sensing, including their first detection of an underground feature, wider applications of quantum sensors such as in healthcare and timing, and a perspective towards future fundamental physics. You will also have the opportunity to see the live generation of cold atom clouds – around a million times colder than liquid nitrogen, and one of the coldest things you can see with your eye – and, for the intrepid, to try cooling and trapping some atoms yourselves.

Registration is required for this talk.

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It is requested that if you feel unwell or have symptoms of COVID, you do not attend. Mask wearing is encouraged but not mandatory. Doors to the Large Lecture Theatre will be open from 7pm and refreshments will be available. The talk begins at 7.30pm.