Improved Look-ahead Approaches for Nearest Neighbor Synthesis of 1D Quantum Circuits

Anirban Bhattacharjee; Chandan Bandyopadhyay; Robert Wille; Rolf Drechsler; Hafizur Rahama

In: IEEE Computer Society Annual Symposium on VLSI (ISVLSI). IEEE Computer Society Annual Symposium on VLSI (ISVLSI-2019), July 15-17, Miami, Florida, USA, 2019.


In the present era of computation, quantum computing may offer a new direction as it allows to solve certain problems significantly faster than classical solutions. But it also has been found that there are several constrains in performing a successful realization of quantum circuits. One such constraint is the nearest neighbor (NN) criterion which statesthat qubits which interact with each other have to be adjacent.Motivated by this objective, in this work we proposea linear qubit placement technique that effectively rearranges the qubits and transforms quantum circuits to improved NN-based designs by inserting SWAPs. Furthermore, for placing these SWAPs in appropriate positions, we implemented a look-ahead strategy that considers the effect ofthe rest of the gates and computes a corresponding impact value which guides the insertion of the SWAP gates. To this extent, we considerthree different strategies to evaluatethe corresponding “look-ahead effects”and their influence onexisting gates.At the end of this work, we have evaluatedthe developed methodology over a wide range of benchmarks and compared the results with existing related works. In thiscomparison, we have seen that the proposed technique outperforms the relatedworksand provides substantial reductions in SWAP overhead.

Deutsches Forschungszentrum für Künstliche Intelligenz
German Research Center for Artificial Intelligence