In this work we identify and investigate a novel bifurcation in conserved systems. This secondary bifurcation stops active phase separation in its nonlinear regime. It is then either replaced by an extended, system-filling, spatially periodic pattern or, in a complementary parameter region, by a novel hybrid state with spatially alternating homogeneous and periodic states. The transition from phase separation to extended spatially periodic patterns is hysteretic. We show that the resulting patterns are multistable, as they show stability beyond the bifurcation for different wavenumbers belonging to a wavenumber band. The transition from active phase separation to the hybrid states is continuous. Both transition scenarios are systems-spanning phenomena in particle conserving systems. They are predicted with a generic dissipative model introduced in this work. Candidates for specific systems, in which these generic secondary transitions are likely to occur, are, for example, generalized models for motility-induced phase separation in active Brownian particles, models for cell division or chemotactic systems with conserved particle dynamics.

在这项工作中，我们确定并研究了保守系统中的新分叉。这种二次分叉停止了其非线性区域的主动相分离。然后，它要么被扩展的、系统填充的、空间周期性的模式所取代，要么在互补参数区域中被具有空间交替均匀和周期性状态的新型混合状态所取代。从相分离到扩展空间周期模式的过渡是滞后的。我们表明所产生的模式是多稳态的，因为它们在属于波数带的不同波数的分岔之外表现出稳定性。从活性相分离到混合状态的转变是连续的。这两种过渡场景都是粒子守恒系统中的跨系统现象。它们是用在这项工作中引入的通用耗散模型来预测的。例如，在活性布朗粒子中运动诱导相分离的广义模型、细胞分裂模型或具有守恒粒子动力学的趋化系统模型，其中可能发生这些通用二次转变的特定系统的候选模型。