The three-dimensional organization of chromatin is influenced by chromatin-binding proteins through both specific and non-specific interactions. However, the roles of chromatin sequence and the interactions between binding proteins in shaping chromatin structure remain elusive. By employing a simple polymer-based model of chromatin that explicitly considers sequence-dependent protein binding and protein–protein interactions, we elucidate a mechanism for chromatin organization. We find that tuning protein–protein interactions and protein concentration is sufficient to either promote or inhibit chromatin compartmentalization. Moreover, chromatin sequence and protein–protein attraction strongly affect the structural and dynamic exponents that describe the spatiotemporal organization of chromatin. Strikingly, our model’s predictions for the exponents governing chromatin structure and dynamics successfully capture experimental observations, in sharp contrast to previous chromatin models. Overall, our findings have the potential to reinterpret data obtained from various chromosome conformation capture technologies, laying the groundwork for advancing our understanding of chromatin organization.
Astrophysical jets associated with supermassive black holes (BHs) are believed to derive their power from the rotational energy of the BH itself, akin to how the Crab Nebula is powered by its pulsar. The Blandford-Znajek (BZ) mechanism, an electromagnetic Penrose process, provides a framework for understanding the physics of jet energetics. Specifically, it predicts the jet efficiency—the ratio of outflowing jet power to inflowing accretion power—to scale quadratically with the magnetic flux at and angular velocity of the black hole horizon. For rapidly spinning Kerr BHs, numerical simulations reveal jet efficiencies exceeding unity, a clear indicator of energy extraction from the black hole. At moderate spins, confirmation of energy extraction relies on the alignment of measured jet efficiencies with the BZ prediction. Over the past decade, this prediction has been validated across Kerr BHs with varying spin values. We present new findings from a large suite of magnetohydrodynamics accretion simulations conducted in spinning non-Kerr spacetimes, demonstrating that the BZ mechanism operates universally, extending its applicability to arbitrary BHs.