Scientists have invented a quantum flute that can make light particles move together

Physicists at the University of Chicago have invented a “quantum flute” that, like a bagpiper, can make light particles move together in a way never seen before.

Described in two studies published in Review of physical sheets and Physics of naturea breakthrough can point the way to realization quantum memories or new forms of error correction in quantum computers, and the observation of quantum phenomena that cannot be seen in nature.

Assoc. Professor David Shuster’s laboratory works quantum bits— the quantum equivalent of a computer bit — that uses the strange properties of particles at the atomic and subatomic level to do things that are otherwise impossible. In this experiment, they worked with light particles known as photons in the microwave spectrum.

The system they came up with consists of a long cavity made in a single block of metal designed to trap photons at microwave frequencies. The cavity is made by drilling offset holes, like holes in a flute.

“The same as in a musical instrument“, Shuster said, “You can send one or more wavelengths of photons through anything, and each wavelength creates a ‘note’ that can be used to encode quantum information.” Researchers can then control the interactions of the “notes” using a master quantum bit, a superconducting electrical circuit.

But the most surprising discovery was how the photons behaved together.

In nature, photons hardly interact—they just pass through each other. With careful preparation, scientists can sometimes make two photons react to each other’s presence.

“We’re doing something even more amazing here,” Schuster said. “At first the photons don’t interact at all, but when total energy it reaches a tipping point in the system and suddenly they’re all talking to each other.”

In a laboratory experiment, so many photons “talk” to each other – it’s very strange, like seeing a cat walking on its hind legs.

“Normally, most particle interactions are one-on-one — two particles bounce off or attract each other,” Schuster said. “When you add a third, they usually still interact sequentially with one or the other. But in this system, they all interact at the same time.”

Their experiments only tested up to five “notes” at a time, but the scientists could eventually imagine running hundreds or thousands of notes through a single qubit to control them. Schuster said the operation is as complex as a quantum computer, and engineers want to simplify it everywhere, Schuster said: “If you wanted to build a quantum computer with 1,000 bits and you could control them all with one bit, it would be incredibly valuable.”

Researchers are also excited about the behavior itself. No one has seen anything like these interactions in nature, so the researchers also hope the discovery could be useful for modeling complex physical phenomena that can’t even be seen here on Earth, including perhaps even some of the physical factors behind black holes. .

Besides, experimenting is just plain fun.

“Typically, quantum interactions occur on time scales too small or fast to see. In our system we can measure one photons in any of our notes and watch the interaction effect as it happens. “It’s really beautiful to see ‘quantum interaction’ with your own eyes,” said University of Chicago doctoral student Srivatsan Chakram, one of the paper’s authors, now an assistant professor at Rutgers University.