Physical-Layer Quantum Error Suppression for Superconducting Qubits in Gate Model Quantum Computation Applications

Quantum computing's advanced capability of handling complex computations has been heralded as a game-changer in fields such as cryptography, machine learning, and physics. However, the susceptibility of qubits, the basic unit of quantum information, to environmental noise and errors poses a crucial challenge. This noise can compromise the reliability and robustness of quantum computations, necessitating effective solutions. The problem with current approaches lies in the tendency to increase circuit complexity or slow down gate operations in an attempt to suppress and rectify errors. Achieving a delicate balance where the quantum system remains stable and well-protected against noise, while not compromising on computational speed and complexity, remains a big hurdle in the mass adoption and practicality of quantum computing technologies.

Technology Description

The technology in question is a device that combines physical qubits into logical ones through the use of a passive, quantum error-suppressing code. It also intertwines these qubits into a computational or annealing fabric by using an active, quantum error-correcting code. The device manages to counter environmental noise, such as thermal fluctuations, by employing enough physical qubits in each logical one. Interaction between individual logical qubits is facilitated via multiple physical qubits interactions; for this, intermediary circuitry that can couple four or more spins is used. What sets this technology apart is its ability to tackle the pesky problem of ambient noise that often interferes with quantum computations. Unlike other approaches, the active and passive codes used do not increase the circuit's complexity or reduce gate operations speed. Integrating an ancilla qubit to the intermediary circuitry facilitates the formation of a logical qubit with passive error suppression, allowing arbitrary computations to be performed using a fabric of such circuitry.