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arXiv 2008.11347quant-ph
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无变分或参数门的混合量子-经典本征求解器

Hybrid Quantum-Classical Eigensolver Without Variation or Parametric Gates

Pejman Jouzdani, Stefan Bringuier

AI总结:

本文提出一种混合量子-经典本征求解器,通过将哈密顿量投影到有限有效希尔伯特空间并用短深度量子线路测量有效哈密顿量,再在经典计算机上对角化,成功获得BeH₂、LiH和H₂分子的基态、激发态及态密度,结果与精确解吻合。

摘要:

利用缺乏量子纠错的近期量子设备来解决量子化学和物理问题,需要混合量子-经典算法和技术。本文提出了一种获取电子量子系统本征能谱的流程。该流程通过将量子系统的哈密顿量投影到由一组计算基所限定的有限有效希尔伯特空间来实现。从该投影中可以得到一个有效哈密顿量。此外,本文还给出了一种制备短深度量子线路的流程,用于测量有效哈密顿量相应的对角项和非对角项,其中利用了量子纠缠和辅助量子比特。随后,在经典计算机上使用数值算法对有效哈密顿量进行对角化,以获得本征值。该方法的应用场景在BeH$_2$和LiH分子的基态和激发态以及态密度上得到了展示,结果与精确解高度吻合。此外,还使用IBM量子设备对H$_2$分子进行了硬件演示。

英文摘要:

The use of near-term quantum devices that lack quantum error correction, for addressing quantum chemistry and physics problems, requires hybrid quantum-classical algorithms and techniques. Here we present a process for obtaining the eigenenergy spectrum of electronic quantum systems. This is achieved by projecting the Hamiltonian of a quantum system onto a limited effective Hilbert space specified by a set of computational bases. From this projection an effective Hamiltonian is obtained. Furthermore, a process for preparing short depth quantum circuits to measure the corresponding diagonal and off-diagonal terms of the effective Hamiltonian is given, whereby quantum entanglement and ancilla qubits are used. The effective Hamiltonian is then diagonalized on a classical computer using numerical algorithms to obtain the eigenvalues. The use case of this approach is demonstrated for ground sate and excited states of BeH$_2$ and LiH molecules, and the density of states, which agrees well with exact solutions. Additionally, hardware demonstration is presented using IBM quantum devices for H$_2$ molecule.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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