Move over science fiction. Can quantum physics help solve very practical problems of the present?


Photo: Nicholas Vevers/ANU.

If you look at a map of the world’s most arid nations, India is colored an ominous shade of red. The same color as notoriously drier nations in North Africa and the Middle East.

However, unlike other water-stressed countries, India is a global agricultural powerhouse and the water crisis is threatening the lives and livelihoods of millions.

Finding a solution is of paramount importance. And researchers are looking for new technologies to help. But could advances in quantum physics actually be part of the answer?

“It might sound like science fiction, but things like atoms being in two places at once can have very practical applications,” says Dr. Simon Haine from the Australian National University Research School of Physics.

One such application is the more accurate measurement of gravity.

“On Earth, gravity varies very slightly from place to place, and the exact measurement depends in part on what’s underneath you.”

dr Simon Hain. Photo: Nicholas Vevers/ANU.

But what does that have to do with water?

dr Haine says measuring fluctuations in the gravitational field on Earth’s surface is a method currently used to find groundwater and mineral deposits.

But these methods are not as accurate as they could be. “Existing devices that measure gravity, called gravimeters, work in a similar way to bathroom scales with springs,” he says.

“These devices are good, but calibration can go wrong. That means you can get two different readings at the same place, which has nothing to do with how the gravitational field actually changed.”

Instead of using springs to measure gravity, Dr. Haine and his colleague Professor John Close Atome. In their lab at ANU, they use an atomic gravimeter that is so precise it can measure changes in gravity caused by someone entering space.

As the world’s largest groundwater producer, India relies on this technology to monitor and control groundwater movements in real time.

To do this, they have to measure gravity on a scale that is so precise that the position of individual atoms becomes relevant.

But due to the whimsical nature of quantum mechanics, it’s difficult to measure gravity with this level of accuracy using single atoms. This is because an atom can be in two places at once and its position is not determined until it is measured. This results in a fuzzy or noisy signal.

Photo: Nicholas Vevers/ANU.

Quantum entanglement can help overcome this limitation.

“When atoms become entangled, they conspire to rearrange themselves in a way that is much less random than the arrangement of individual atoms,” says Dr. groves.

“By introducing quantum entanglement, we can increase the sensitivity of our atomic gravimeter by a factor of up to 1000.”

dr Haine and Professor John Close have received an Australia-India Strategic Research Fund grant from the Australian Government to develop a quantum gravimeter. To do this, they will work with researchers from the Indian Institute of Science Education and Research, Pune; the Indian Institute of Science Education and Research, Bhopal; and the University of Queensland.

As part of this collaboration, colleagues in India plan to deploy the device in the field to closely monitor groundwater movements. Enables better management of groundwater resources, which is a major contributor to India’s deepening water crisis.

Groundwater monitoring is not the only practical application of today’s quantum technology. As the shift to zero-carbon technologies accelerates, more accurate methods of locating the rare earth minerals needed for these technologies are becoming more relevant.

according to dr Haine, quantum gravimetry is just one example of how advances in quantum physics are fueling a new growth industry.

“There are applications where people would absolutely pay a lot of money to measure gravity very accurately,” he says.

“This technology is not as far in the future as you might think.”


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