Hardware-efficient entangled measurements for variational quantum algorithms

Understand

Variational algorithms have received significant attention in recent years due to their potential to solve practical problems using noisy intermediate-scale quantum (NISQ) devices.

• A fundamental step of these algorithms is the evaluation of the expected value of Hamiltonians, and hence efficient schemes to perform this task are required.
• The standard approach employs local measurements of Pauli operators and requires a large number of circuits.
• An alternative is to make use of entangled measurements, which might introduce additional gates between physically disconnected qubits that harm the performance.