Quantum State Preparation by Improved MPS Method

TL;DR

This paper introduces an improved MPS-based quantum state preparation method that significantly reduces circuit depth and gate count, enabling more efficient and higher fidelity encoding of classical information on noisy quantum devices.

Contribution

The authors develop an enhanced MPS protocol with exponential circuit depth reduction and approximately 33% fewer two-qubit gates, improving state preparation efficiency.

Findings

Reduces circuit depth significantly

Achieves higher fidelity in state preparation

Effective for states with bounded MPS rank

Abstract

Efficient encoding of classical information plays a fundamental role in numerous practical quantum algorithms. However, the preparation of an arbitrary amplitude-encoded state has been proven to be time-consuming, and its deployment on current noisy devices can be challenging. In this work, we propose an improved Matrix Product State(MPS) method preparation protocol with an exponential reduction on the circuit depth, as well as topological adaptability. By refined utilization of the disentangling principle, we also reduce approximately 33% two-qubit gate count. To validate our method, we study various families of functions and distributions with provably bounded MPS rank. Numerical experiments show that our method significantly reduces circuit depth while achieving higher fidelity for states arising in financial and other applications.