For the characterization of dynamics in quantum many-body systems the question how information spreads and becomes distributed over the constituent degrees of freedom is of fundamental interest. The delocalization of information under many-body dynamics has been dubbed "scrambling" and out-of-time-order correlators were proposed to probe this behavior. In this work we investigate the time-evolution of tripartite information as a natural operator-independent measure of scrambling, which quantifies to which extent the initially localized information can only be recovered by global measurements. Studying the dynamics of quantum lattice models with tunable integrability breaking we demonstrate that in contrast to quadratic models a generic non-integrable system scrambles information irrespective of the chosen partitioning of the Hilbert space, which justifies the characterization as "scrambler." In the quadratic model the delocalization of information strongly depends on the notion of locality introduced by the choice of a Hilbert space partitioning.Introduction. The concept of scrambling was originally devised to study the information paradox of black holes [1,2]. A scrambler is a quantum system with many degrees of freedom in which information about local fluctuations in the initial state is under dynamics strongly mixed up such that it can after long times only be recovered by global measurements. It was found that black holes can be regarded as the most efficient scramblers [3]. The idea of scrambling is of interest also in quantum many-body systems beyond the AdS/CFT paradigm, where the spreading of correlations and information is a subject of ongoing research [4][5][6][7][8][9][10] as well as the question of thermalization after a system was prepared far from equilibrium [11,12] and how information about the initial conditions is lost [13][14][15][16][17][18]. Since the timescales of thermalization and scrambling can strongly differ, a central question is whether there is nevertheless a connection between both [19].

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