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Quantum network ensures accurate measurements of multiple objects

Monday 13 Jan 20


Ulrik Lund Andersen
DTU Physics
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Researchers have shown that it is possible to increase the level of precision when conducting similar measurements on multiple objects simultaneously via quantum networks.

When discussions turn to quantum mechanics, you often hear people saying things such as ‘In quantum mechanics, things can be in two places at the same time’. Most people probably feel more confused than enlightened when hearing this.

But however odd it sounds, there is some truth in it. And the experiments confirm it time and again. In a new study which has been published in the highly reputed scientific journal Nature Physics, researchers from the basic research centre bigQ at DTU Physics and at the Villum Centre for the Mathematics of Quantum Theory (QMATH) at the University of Copenhagen have shown that by using quantum-correlated light, it is possible to achieve clear improvements when measuring many separate objects at the same time—a technique known as ‘distributed sensing’.

More accurate results

What the researchers have done is to measure the phase shift—or the delay in the spread of light—in four different glass sheets placed in four different locations. They have shown that the quantum physical approach to the task yields more accurate results in determining the average measurement result than if the measurements are made one at a time.

The experiment is the first of its kind to illustrate the potential of quantum networks, where spatially distributed nodes are entangled into a single unit with perfect internal synchronization. This may be useful for, among other things, synchronizing atomic clocks and measuring molecular movements in cells.

“Four nodes distributed on an optical table in a laboratory may not sound like much, but the technology can easily be transferred to a fibre-optic network, and then the nodes can suddenly be very far apart,” says Professor Ulrik Lund Andersen, DTU Physics.

Concrete plans are already in place to establish such a quantum network across Europe, and thus create a completely new communication infrastructure based on quantum technology.
As the results show, Danish research is right up there at the front.

Read the article in Nature Physics

Distributed quantum sensing in a continuous variable entangled network