Quanto: Optimizing Quantum Circuits with Automatic Generation of Circuit
  Identities
Existing quantum compilers focus on mapping a logical quantum circuit to a
quantum device and its native quantum gates. Only simple circuit identities are
used to optimize the quantum circuit during the compilation process. This
approach misses more complex circuit identities, which could be used to
optimize the quantum circuit further. We propose Quanto, the first quantum
optimizer that automatically generates circuit identities. Quanto takes as
input a gate set and generates provably correct circuit identities for the gate
set. Quanto's automatic generation of circuit identities includes single-qubit
and two-qubit gates, which leads to a new database of circuit identities, some
of which are novel to the best of our knowledge. In addition to the generation
of new circuit identities, Quanto's optimizer applies such circuit identities
to quantum circuits and finds optimized quantum circuits that have not been
discovered by other quantum compilers, including IBM Qiskit and Cambridge
Quantum Computing Tket. Quanto's database of circuit identities could be
applied to improve existing quantum compilers and Quanto can be used to
generate identity databases for new gate sets.
Jessica Pointing Oded Padon Zhihao Jia Henry Ma Auguste Hirth Jens Palsberg Alex Aiken