Quantum computers also need multiple processors parts to share quantum information. Today’s designs for connecting quantum processors use a “point-to-point” method. This means information moves through many steps, and errors pile up along the way.
MIT researchers found a better way. They built a device that lets all quantum processors talk directly to each other. This is called “all-to-all” communication. They tested it with two processors. These processors sent photons back and forth using microwaves. Photons carry quantum information. A wire, known as a waveguide, moves photons between processors. This wire can stretch as far as needed and connect many processors. This setup sends information smoothly across a big network.
The researchers used microwave pulses to control the photons. When a qubit gets energy, it releases a photon. By tweaking the pulses, the team directed photons along the waveguide. Another processor far away could catch the photon by reversing the pulses.
A scalable architecture
Earlier, the researchers made a module that sent photons in either direction along a waveguide. Now, they linked two modules to share photons. Each module has four qubits. These qubits grab and release photons, passing them to nearby data qubits. The team used pulses to control the photon’s path with quantum interference. Halfway through the pulses, they stopped. This trick left the photon half-sent and half-kept. When the second module caught this “half-photon,” the two modules became entangled.
The researchers have described the methods and results of this study in a paper published in Nature Physics.
To make this work well, the reserchers faced challenges. Connections in the waveguide can mess up the photon. The researchers used a smart algorithm to fix this and got over 60 percent success. This proved the processors were entangled. In the future, this could connect many processors in a flexible network. The researchers hope to improve it by tweaking the photon’s path and speeding things up. This could help build bigger quantum systems.