论文标题
Quasiparticle相互作用的发散非线性响应
Divergent nonlinear response from quasiparticle interactions
论文作者
论文摘要
我们证明，多体系统中的非线性响应功能具有尖锐的低能量准颗粒之间相互作用的敏锐特征。从线性响应测量结果推断出这种相互作用具有挑战性。该签名采取了对响应的及时贡献的形式 - 在准粒子以弹道传播的情况下，随着时间的推移是线性的，这是不存在的自由骨气激发。我们给出了这种奇异行为的直观半经典图片，并通过在不可融合模型-SPIN-1 AKLT链中的ISING链和TDMRG模拟的形式扩展的确切结果进行了验证。我们将这些结果扩展到更一般的设置，有限温度和更高的维度。
We demonstrate that nonlinear response functions in many-body systems carry a sharp signature of interactions between gapped low-energy quasiparticles. Such interactions are challenging to deduce from linear response measurements. The signature takes the form of a divergent-in-time contribution to the response -- linear in time in the case when quasiparticles propagate ballistically -- that is absent for free bosonic excitations. We give an intuitive semiclassical picture of this singular behaviour, validated against exact results from a form-factor expansion of the Ising chain and tDMRG simulations in a non-integrable model -- the spin-1 AKLT chain. We comment on extensions of these results to more general settings, finite temperature, and higher dimensions.
