A pair of distant cosmic black hole mergers, measured just one month apart in late 2024, is improving how scientists understand the nature and evolution of the most violent deep-space collisions in our universe. Data collected from the mergers also validates, with unprecedented accuracy, fundamental laws of physics that were predicted more than 100 years ago by Albert Einstein and furthers the search for new and still unknown elementary particles with the potential to extract energy from black holes. 

In a new paper published Oct. 28 in The Astrophysical Journal Letters, the international LIGO-Virgo-KAGRA Collaboration reports on the detection of two gravitational wave events in October and November of last year with unusual black hole spins. 

The exploration-exploitation dilemma is a long-standing topic in deep reinforcement learning. In recent research, a noise-driven enhancement for exploration algorithm has proposed for UAV autonomous navigation. This algorithm introduces a differentiated exploration noise control strategy based on the global navigation training hit rate and the specific situations encountered by the UAV in each episode. Furthermore, it designs a noise dual experience replay buffer to amplify the distinct effects of noisy and deterministic experiences. This approach reduces the computational cost associated with excessive exploration and mitigates the problem of the navigation policy converging to a local optimum.

Orbital angular momentum (OAM) of light offers transformative potential for optical technologies, yet current efforts largely focus on spatial-only control within a single pulse, leaving dynamic space-time manipulation limited. Toward this goal, researchers in China proposed a novel concept of a spatiotemporal vortex comb with time-varying photon features, including transverse OAM density and chirality, realized through a spatiotemporal multiplexing technique. This technique may facilitate applications in ultrafast light-matter interactions, quantum information, spatiotemporal topology and metrology.