Spectral truncation of out-of-time-ordered correlators in dissipative system

Abstract: Out-of-time-ordered correlators (OTOCs) have emerged as powerful tools for diagnosing quantum chaos and information scrambling. While extensively studied in closed quantum systems, their behavior in dissipative environments remains less understood. In this work, we investigate the spectral decomposition of OTOCs in open quantum systems, using the dissipative modified kicked rotator (DMKR) as a paradigmatic model. By analyzing the eigenvalue spectrum of the quantum Liouvillian, we identify a crucial spectral truncation criterion that enables efficient modeling of OTOC dynamics. Our results reveal two distinct temporal regimes: a long-time decay phase governed by the spectral gap and an intermediate-time regime where a small subset of subdominant eigenvalues plays a crucial role. This spectral truncation criterion allows for efficient modeling of OTOC decay and reveals a direct connection between eigenvalue structure and information scrambling. Our results provide a quantitative framework for understanding OTOCs in dissipative quantum systems and suggest new avenues for experimental exploration in open quantum platforms.