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arXiv · 2607.12802

A Variational Surrogate Approach to Finite-Horizon Quantum Control via Hardware-Efficient Ansatz

Nahid Binandeh Dehaghani·Rafal Wisniewski·A. Pedro Aguiar
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Abstract

We present a variational quantum framework for finite-horizon quantum control based on hardware-efficient ans\"atze. The objective is to steer a quantum system from a given initial state to a desired target state over a fixed time horizon by minimizing a terminal cost defined in terms of state fidelity. Instead of explicitly synthesizing time-dependent control fields or enforcing Hamiltonian reachability constraints, the proposed method reformulates the control objective as a variational optimization problem in which a hardware-efficient parameterized quantum circuit provides a surrogate parameterization of the terminal evolution. The circuit consists of alternating layers of single-qubit rotations and entangling gates, whose parameters are optimized using classical routines to minimize the terminal infidelity. This formulation avoids reliance on problem-specific or physics-inspired ans\"atze, providing a flexible and implementation-friendly approach compatible with near-term quantum devices. Numerical experiments on multi-qubit state-transfer benchmarks demonstrate high-fidelity state transfer while highlighting the trade-off between ansatz expressivity, optimization complexity, and scalability with respect to system size and circuit depth.

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Nahid Binandeh Dehaghani, Rafal Wisniewski, A. Pedro Aguiar. 2026-07-14. A Variational Surrogate Approach to Finite-Horizon Quantum Control via Hardware-Efficient Ansatz. https://arxiv.org/abs/2607.12802

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