Exploiting Qubit Reuse through Mid-circuit Measurement and Reset
Quantum measurement is important to quantum computing as it extracts the
outcome of the circuit at the end of the computation. Previously, all
measurements have to be done at the end of the circuit. Otherwise, it will
incur significant errors. But it is not the case now. Recently IBM started
supporting dynamic circuits through hardware (instead of software by
simulator). With mid-circuit hardware measurement, we can improve circuit
efficacy and fidelity from three aspects: (a) reduced qubit usage, (b) reduced
swap insertion, and (c) improved fidelity. We demonstrate this using real-world
applications Bernstein Verizani on real hardware and show that circuit resource
usage can be improved by 60\%, and circuit fidelity can be improved by 15\%. We
design a compiler-assisted tool that can find and exploit the tradeoff between
qubit reuse, fidelity, gate count, and circuit duration. We also developed a
method for identifying whether qubit reuse will be beneficial for a given
application. We evaluated our method on a representative set of essential
applications. We can reduce resource usage by up to 80\% and circuit fidelity
by up to 20\%.
Fei Hua Yuwei Jin Yanhao Chen Suhas Vittal Kevin Krsulich Lev S. Bishop John Lapeyre Ali Javadi-Abhari Eddy Z. Zhang