Researchers "teleport" a quantum gate

Researchers at Yale University have demonstrated one of the key steps in building the architecture of modular quantum computers: the "teleportation" of a quantum gate between two qubits, to the demand.

The results appear online on September 5 in the journal Nature.

The key principle of this new work is quantum teleportation, a unique feature of quantum mechanics that has already been used to transmit unknown quantum states between two parts without physically sending the state itself. Using a theoretical protocol developed in the 1990s, Yale researchers experimentally demonstrated a quantum operation, or "gate," without resorting to direct interaction. Such gates are needed for quantum computing that relies on distinct quantum systems networks – an architecture that many researchers believe can offset the inherent errors of quantum computing processors.

Through the Yale Quantum Institute, a Yale research team led by lead researcher Robert Schoelkopf and former graduate student Kevin Chou is studying a modular approach to quantum computing. The modularity, which is found in everything from the organization of a biological cell to the engine network of the latest SpaceX rocket, has proven to be a powerful strategy for building large complex systems, according to the researchers. A quantum modular architecture consists of a collection of modules operating as small quantum processors connected to a larger network.

The modules in this architecture are naturally isolated from each other, reducing unwanted interactions through a larger system. However, according to the researchers, this isolation also makes it difficult to perform operations between modules. The teleported doors are a way to implement inter-module operations.

"Our work is the first time this protocol has been demonstrated where classical communication occurs in real time, which allows us to implement a" deterministic "operation that performs the desired operation every time," he said. said Chou.

Fully useful quantum computers can reach higher computational speeds than current supercomputers. Yale researchers are at the forefront of efforts to develop the world's first fully useful quantum computers, and have done groundbreaking work in quantum computing with superconducting circuits.

Quantum computations are performed via tricky data bits called qubits, which are prone to errors. In experimental quantum systems, "logical" qubits are monitored by "auxiliary" qubits to detect and correct errors immediately. "Our experience is also the first demonstration of a two-qubit operation between logical qubits," said Schoelkopf. "This is an important step in the processing of quantum information using correctable qubits."

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More information:
Kevin S. Chou et al. Deterministic teleportation of a quantum gate between two logical qubits, Nature (2018). DOI: 10.1038 / s41586-018-0470-y