Description
Limited qubit connectivity challenges practical deployment of quantum algorithms on quantum processors. When a gate between not-neighboring qubits is implemented, the qubit state must be moved to a nearby connected qubit for local execution, achieved typically through a series of SWAP operations and leading to increased circuit depth, gate count, and reduced total error performance.
This work explores teleported gates to improve qubit routing efficiency. Our practical routing method balances between SWAP paths and teleported gates to reduce circuit depths and error accumulation.
We implement the teleported-assisted routing method by modifying the Qiskit-native routing routines and benchmark it with various algorithms, e.g. Deutsch–Jozsa, quantum Fourier transform and the quantum approximation optimization algorithms on heavy-hexagon qubit topology. Our results show a 10%–25% depth reduction in the routing of selected algorithms compared to regular SWAP-only routing. Furthermore, for certain cases, we found that directly teleporting controlled unitaries is highly beneficial over teleporting CNOT gates.
