Simulating a quantum magnet with trapped ions
Simulating a quantum magnet with trapped ions
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DOI：
10.1038/nphys1032
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发表时间：
2008-10-01
期刊：
影响因子：
19.6
通讯作者：
Schaetz, T.
中科院分区：
文献类型：
--
作者：
Friedenauer, A.;Schmitz, H.;Schaetz, T.
为了更深入地了解复杂量子系统的动力学，我们需要在计算机模拟方面进行一次量子飞跃。我们无法将叠加态或纠缠产生的量子行为有效地转化为传统计算机的经典语言。这一问题的解决方案，于1982年提出。1)，是在一个不同的量子系统中模拟感兴趣的量子行为，在这个系统中，相互作用可以被控制，结果被检测得足够好。在这里，我们研究了用囚禁离子模拟量子自旋哈密顿量的构件(2)。我们实验模拟了最小非平凡自旋系统从顺磁到铁磁有序的绝热演化，其中两个自旋的量子磁化强度为98%。我们证明了这种相变不是由热涨落驱动的，而是源于量子力学的(类似于量子相变中的量子涨落[3])。我们观察到铁磁有序的两种简并自旋组态(竖杆向上箭头+竖杆向下箭头)的最终叠加态，对应于88%保真度的确定性纠缠。这种方法应该允许扩展到更多的耦合自旋(2)，从而能够实现在传统计算机上难以处理的模拟。
To gain deeper insight into the dynamics of complex quantum systems we need a quantum leap in computer simulations. We cannot translate quantum behaviour arising from superposition states or entanglement efficiently into the classical language of conventional computers. The solution to this problem, proposed in 1982 (ref. 1), is simulating the quantum behaviour of interest in a different quantum system where the interactions can be controlled and the outcome detected sufficiently well. Here we study the building blocks for simulating quantum spin Hamiltonians with trapped ions(2). We experimentally simulate the adiabatic evolution of the smallest non-trivial spin system from paramagnetic into ferromagnetic order with a quantum magnetization for two spins of 98%. We prove that the transition is not driven by thermal fluctuations but is of quantum-mechanical origin ( analogous to quantum fluctuations in quantum phase transitions(3)). We observe a final superposition state of the two degenerate spin configurations for the ferromagnetic order (vertical bar up arrow up arrow + vertical bar down arrow down arrow), corresponding to deterministic entanglement achieved with 88% fidelity. This method should allow for scaling to a higher number of coupled spins(2), enabling implementation of simulations that are intractable on conventional computers.