New device allows direct communication among quantum processors

Researchers have created a new device that allows multiple quantum processors to communicate with each other directly. This development is important for building powerful quantum networks that can solve complex problems more efficiently than traditional computers. The device functions as an “interconnect,” which helps quantum processors exchange information without going through lengthy back-and-forth processes. Current systems often lead to errors because information travels through several points. The new interconnect connects quantum processors so they can communicate freely with each other. Using this interconnect, the team demonstrated a process called remote entanglement. This involves creating a unique link between processors that are not physically connected. Such entanglement is crucial for developing advanced quantum networks. The researchers used a superconducting wire that transports photons, which are particles of light that carry quantum information. They tested their system with two quantum processors and successfully sent and received photons in specific directions on demand. Each processor in the study includes qubits, which are the basic units of quantum information. These qubits send and receive the photons through the wire, allowing information to be processed. By controlling the timing of pulses sent to the qubits, the researchers could ensure that photons traveled in both directions effectively. One challenge was ensuring the photons' quality during transport, as obstacles could distort them. To address this, the team employed a machine learning technique to predict and adjust the photon shape for optimal transfer. This method increased their photon absorption efficiency, which is necessary for reliable entanglement. The researchers reported an ability to achieve more than 60% absorption efficiency, a significant milestone that shows how well their system works. This achievement means they can establish remote entanglement between any two processors in their network. Looking ahead, the team believes their technology could be even more effective if integrated using three-dimensional designs. They also aim to increase speed and reduce potential errors in the communication process. This research could pave the way for larger quantum networks in the future, expanding the capabilities of quantum computing. The work received funding from various organizations, including the U.S. Army Research Office and the AWS Center for Quantum Computing.