Center-of-mass motion as a sensitive convergence test for variational multimode quantum dynamics
Center-of-mass motion as a sensitive convergence test for variational multimode quantum dynamics
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DOI：
10.1103/physreva.94.043603
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发表时间：
2015-10
影响因子：
2.9
通讯作者：
Jayson G. Cosme;C. Weiss;J. Brand
中科院分区：
文献类型：
--
作者：
Jayson G. Cosme;C. Weiss;J. Brand
计算量子动力学中的多模展开保证了在增加模的数量时收敛到精确的结果。收敛是很难确定在实践中，由于不利的缩放所需的资源为多粒子问题，因此，一个简化的标准的基础上的阈值最少占用的模式函数经常使用。在这里，我们展示了如何可分离的量子运动的质量中心可以用来灵敏地检测不收敛的数值多粒子动力学的谐波势。基于一个实验相关的例子吸引相互作用玻色子在一维，我们表明，简化的收敛准则不能保证定性正确的结果。此外，还给出了A。I. Streltsov等人[Phys. Rev. Lett. 100，130401（2008）]显示与精确结果不一致。简要讨论了理解吸引玻色子系统中动力学碎裂的意义。
Multimode expansions in computational quantum dynamics promise convergence toward exact results upon increasing the number of modes. Convergence is difficult to ascertain in practice due to the unfavorable scaling of required resources for many-particle problems and therefore a simplified criterion based on a threshold value for the least occupied mode function is often used. Here we show how the separable quantum motion of the center of mass can be used to sensitively detect unconverged numerical multiparticle dynamics in harmonic potentials. Based on an experimentally relevant example of attractively interacting bosons in one dimension, we demonstrate that the simplified convergence criterion fails to assure qualitatively correct results. Furthermore, the numerical evidence for the creation of two-hump fragmented bright soliton-like states presented by A. I. Streltsov et al. [Phys. Rev. Lett. 100, 130401 (2008)] is shown to be inconsistent with exact results. Implications for understanding dynamical fragmentation in attractive boson systems are briefly discussed.