Optimal quantum circuit cuts with application to clustered Hamiltonian simulation

Understand

We study methods to replace entangling operations with random local operations in a quantum computation, at the cost of increasing the number of required executions.

• First, we consider "space-like cuts" where an entangling unitary is replaced with random local unitaries.
• We propose an entanglement measure for quantum dynamics, the product extent, which bounds the cost in a procedure for this replacement based on two copies of the Hadamard test.
• In the terminology of prior work, this procedure yields a quasiprobability decomposition with minimal 1-norm in a number of cases, which addresses an open question of Piveteau and Sutter.