Dynamics of position-disordered Ising spins with a soft-core potential

• Verfasst von: Tan, Canzhu [VerfasserIn]
• Verfasst von: Lin, Xiaodong [VerfasserIn]
• Verfasst von: Zhou, Yabing [VerfasserIn]
• Verfasst von: Jiang, Yuhai [VerfasserIn]
• Verfasst von: Weidemüller, Matthias [VerfasserIn]
• Verfasst von: Zhu, Bing [VerfasserIn]
• Titel: Dynamics of position-disordered Ising spins with a soft-core potential
• Verf.angabe: Canzhu Tan, Xiaodong Lin, Yabing Zhou, Yuhai Jiang, Matthias Weidemüller, and Bing Zhu
• E-Jahr: 2022
• Jahr: 23 March 2022
• Umfang: 6 S.
• Fussnoten: Gesehen am 13.07.2022
• Titel Quelle: Enthalten in: Physical review
• Ort Quelle: Woodbury, NY : Inst., 2016
• Jahr Quelle: 2022
• Band/Heft Quelle: 105(2022), 10, Artikel-ID 104204, Seite 1-6
• ISSN Quelle: 2469-9969
• DOI: doi:10.1103/PhysRevB.105.104204
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1810076498

Abstract

We theoretically study the magnetization relaxation of Ising spins distributed randomly in a d-dimension homogeneous and Gaussian profile under a soft-core two-body interaction potential ∝1/[1+(r/Rc)α] (α≥d), where r is the interspin distance and Rc is the soft-core radius. The dynamics starts with all spins polarized in the transverse direction. In the homogeneous case, an analytic expression is derived at the thermodynamic limit, which starts as ∝exp(−kt2) with a constant k and follows a stretched-exponential law at long time with an exponent β=d/α. In between an oscillating behavior is observed with a damping amplitude. For Gaussian samples, the degree of disorder in the system can be controlled by the ratio lρ/Rc, with lρ the mean interspin distance and the magnetization dynamics is investigated numerically. In the limit of lρ/Rc≪1, a coherent many-body dynamics is recovered for the total magnetization despite the position disorder of spins. In the opposite limit of lρ/Rc≫1, a similar dynamics as that in the homogeneous case emerges at a later time after a initial fast decay of the magnetization. We obtain a stretched exponent of β≈0.18 for the asymptotic evolution with d=3,α=6, which is different from that in the homogeneous case (β=0.5).