🤖 AI Summary
该研究解决了时间依赖哈密顿量模拟中的高门开销问题,通过一种新的实现方法,在保持最优查询复杂度的同时减少了所需的一、二量子比特门数量。
📝 Abstract
The query-optimal algorithm of [CGWZ26] for general time-dependent Hamiltonian simulation uses $$
q = O\left( αT +
\frac{\log(1/\varepsilon)}{\log\left(e + \log(1/\varepsilon)/(αT) \right)}
\right) $$ queries to $\mathrm{HAM\mbox{-}T}$ within $\varepsilon$ error for a Lipschitz-continuous time-dependent Hamiltonian $H(t)$ on $[0,T]$ satisfying $\left\lVert H(t)\right\rVert\leqα$. However, its direct circuit implementation incurs a substantially larger gate overhead. In this note, we give an implementation of the same algorithm that retains its optimal query complexity and uses $$
O\left[ q \left( a + \log\left(1 + \frac{T(α+ βT)}{\varepsilon}
\right) \right) \right] $$ one- and two-qubit gates, where $a$ is the number of block-encoding ancilla qubits and $β$ is the Lipschitz constant of $H$. The main ingredient is an exact dyadic factorization of the ordered update product in the underlying one-query transducer.