Department of Physics, Southeast University, Nanjing, 211189, China.
State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200062, China.
Sci Rep. 2017 May 19;7(1):2183. doi: 10.1038/s41598-017-02571-w.
We experimentally demonstrate a photonic quantum simulator: by using a two-spin Ising chain (an isolated dimer) as an example, we encode the wavefunction of the ground state with a pair of entangled photons. The effect of magnetic fields, leading to a critical modification of the correlation between two spins, can be simulated by just local operations. With the ratio of simulated magnetic fields and coupling strength increasing, the ground state of the system changes from a product state to an entangled state and back to another product state. The simulated ground states can be distinguished and the transformations between them can be observed by measuring correlations between photons. This simulation of the Ising model with linear quantum optics opens the door to the future studies which connect quantum information and condensed matter physics.
通过使用双自旋 Ising 链（一个孤立的二聚体）作为示例，我们用一对纠缠光子编码基态的波函数。磁场的影响导致两个自旋之间的相关性发生临界变化，这种影响可以通过局部操作来模拟。随着模拟磁场与耦合强度之比的增加，系统的基态从一个乘积态变为一个纠缠态，然后再回到另一个乘积态。通过测量光子之间的相关性，可以区分模拟的基态，并观察它们之间的转换。这种利用线性量子光学模拟 Ising 模型的方法为连接量子信息和凝聚态物理的未来研究开辟了道路。
