Localization induced by quantized fields

Periodic driving can lead to novel phenomena and enrich the dynamics of quantum systems, including the so called dynamical localization. However, little was known whether the dynamical localization can still exist when the driving is replaced by a quantized field. We study this problem by analyzing the localization properties of a spin chain coupled globally to a single mode quantized field. We calculate numerically the eigenstates of the spin-field composite system and find that two types of eigenstates with different localization properties coexist in the system. When the eigenfrequency of the field is larger than the band width of the single particle spectrum of the spin chain, the eigenstates of system can be approximated by product states, and the spin part is either localized or extended depending on the state of the field part. The localization of spin excitation can be controlled by exciting the field to appropriate quantum states.

Automated summary

This study investigates the localization properties of a spin chain coupled to a quantized field and identifies two types of eigenstates with different localization properties in the system. The localization of spin excitation can be controlled by exciting the field to appropriate quantum states.