September 30, 2022

Iterative Quantum Amplitude Estimation

Iterative Quantum Amplitude Estimation Iterative quantum amplitude estimation

A team of researchers at IBM Quantum and ETH, Switzerland, has introduced a variant of Quantum Amplitude Estimation (QAE), called Iterative QAE (IQAE), which does not rely on Quantum Phase Estimation (QPE) but is only based on Grover’s Algorithm, which reduces the required number of qubits and gates.

QAE is a work horse behind many quantum algorithms for pricing and risk analysis of financial instruments.

They provided a rigorous analysis of IQAE and proved that it achieves a quadratic speedup up to a double-logarithmic factor compared to classical Monte Carlo simulation with provably small constant overhead.

Furthermore, they showed with an empirical study that their algorithm outperforms other known QAE variants without QPE, some even by orders of magnitude, i.e., their algorithm requires significantly fewer samples to achieve the same estimation accuracy and confidence level.

The paper has been published in npj Quantum Information.