Quantum computers are powerful machines that could one day solve problems far beyond the abilities of today’s fastest supercomputers.
But for them to work on a large scale, their different parts—or processors—must be able to talk to each other quickly and reliably.
That’s where a new invention from MIT comes in.
Just like how parts of a regular computer, like the CPU and memory chip, need to work together, quantum computers will also need to share information across many processors.
Right now, most ways to connect quantum processors only allow information to pass one step at a time from one point to another.
This kind of connection, called “point-to-point,” can lead to errors as the message is passed along.
To fix this, MIT researchers have created a new kind of device that lets all quantum processors in a network talk to each other directly. This setup, called “all-to-all” communication, is much more scalable and efficient.
Their new device connects two quantum processors using a special wire, known as a superconducting waveguide, which carries tiny particles of light called photons. These photons carry quantum information and can be sent back and forth on demand, in either direction.
Each processor has four small units called qubits, which are the building blocks of quantum computers.
Some qubits are responsible for sending and receiving photons along the waveguide, while others hold the data. The researchers use microwave energy to excite the qubits, causing them to release a photon.
They can then carefully control the direction of the photon and send it to another processor, even one far away.
This setup allowed the team to achieve remote entanglement, a strange quantum connection where two processors become linked, even though they’re not physically touching. Once entangled, they can work together as if they were next to each other. This is a big step toward building larger quantum networks.
To make the connection strong enough, the photon must be absorbed properly when it reaches the second processor.
This was a challenge because as the photon travels through the waveguide, it can be distorted by bumps or connections in the wire. So, the researchers used reinforcement learning—a type of artificial intelligence—to “pre-shape” the photon before it was sent. This helped increase the success rate of the photon being absorbed on the other end.
Thanks to this technique, they achieved an absorption efficiency of more than 60%, which is enough to prove the processors were truly entangled.
In the future, this system could allow many quantum processors to connect along the same wire, forming a flexible, high-speed quantum network. The team hopes to improve the design further by shortening the travel path or arranging the parts in 3D to reduce errors.
This breakthrough not only helps build better quantum computers but could also play a role in building a global quantum internet someday.
