Error-divisible two-qubit gates

  1. David Rodriguez Perez,
  2. Paul Varosy,
  3. Ziqian Li,
  4. Tanay Roy,
  5. Eliot Kapit,
  6. and David Schuster
We introduce a simple, widely applicable formalism for designing „error-divisible“ two qubit gates: a quantum gate set where fractional rotations have proportionally reduced
error compared to the full entangling gate. In current noisy intermediate-scale quantum (NISQ) algorithms, performance is largely constrained by error proliferation at high circuit depths, of which two-qubit gate error is generally the dominant contribution. Further, in many hardware implementations, arbitrary two qubit rotations must be composed from multiple two-qubit stock gates, further increasing error. This work introduces a set of criteria, and example waveforms and protocols to satisfy them, using superconducting qubits with tunable couplers for constructing continuous gate sets with significantly reduced error for small-angle rotations. If implemented at scale, NISQ algorithm performance would be significantly improved by our error-divisible gate protocols.