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Solitons, the distinct balance between nonlinearity and dispersion, provide a route toward ultrafast electromagnetic pulse shaping, high-harmonic generation, real-time image processing, and RF photonic communications. Here we uniquely explore and observe the spatio-temporal breather dynamics of optical soliton crystals in frequency microcombs, examining spatial breathers, chaos transitions, and dynamical deterministic switching – in nonlinear measurements and theory. To understand the breather solitons, we describe their dynamical routes and two example transitional maps of the ensemble spatial breathers, with and without chaos initiation. We elucidate the physical mechanisms of the breather dynamics in the soliton crystal microcombs, in the interaction plane limit cycles and in the domain-wall understanding with parity symmetry breaking from third-order dispersion. We present maps of the accessible nonlinear regions, the breather frequency dependences on third-order dispersion and avoided-mode crossing strengths, and the transition between the collective breather spatio-temporal states. Our range of measurements matches well with our first-principles theory and nonlinear modeling. To image these soliton ensembles and their breathers, we further constructed panoramic temporal imaging for simultaneous fast- and slow-axis two-dimensional mapping of the breathers. In the phase-differential sampling, we present two-dimensional evolution maps of soliton crystal breathers, including with defects, in both stable breathers and breathers with drift. Our fundamental studies contribute to the understanding of nonlinear dynamics in soliton crystal complexes, their spatio-temporal dependences, and their stability-existence zones.

 

Multi-Agent Reinforcement Learning (MARL) is a key technology in artificial intelligence applications such as robotics, surveillance, energy systems, etc. Multi-Agent Deep Deterministic Policy Gradient (MADDPG) is a state-of-the-art MARL algorithm that has been widely adopted and considered a popular baseline for novel MARL algorithms. However, existing implementations of MADDPG on CPU and CPU-GPU platforms do not exploit fine-grained parallelism between cooperative agents and handle inter-agent communication sequentially, leading to sub-optimal throughput performance in MADDPG training. In this work, we develop the first high-throughput MADDPG accelerator on a CPU-FPGA heterogeneous platform. Specifically, we develop dedicated hardware modules that enable parallel training of each agent's internal Deep Neural Networks (DNNs) and support low-latency inter-agent communication using an on-chip agent interconnection network. Our experimental results show that the speed performance of agent neural network training improves by a factor of 3.6×−24.3× and 1.5×−29.5× compared with state-of-the-art CPU and CPU-GPU implementations. Our design achieves up to a 1.99× and 1.93× improvement in overall system throughput compared with CPU and CPU-GPU implementations, respectively. 

Polyploidy (genome duplication) is a pivotal force in evolution. However, the interactions between parental genomes in a polyploid nucleus, frequently involving subgenome dominance, are poorly understood. Here we showcase analyses of a bamboo system (Poaceae: Bambusoideae) comprising a series of lineages from diploid (herbaceous) to tetraploid and hexaploid (woody), with 11 chromosome-level de novo genome assemblies and 476 transcriptome samples. We find that woody bamboo subgenomes exhibit stunning karyotype stability, with parallel subgenome dominance in the two tetraploid clades and a gradual shift of dominance in the hexaploid clade. Allopolyploidization and subgenome dominance have shaped the evolution of tree-like lignified culms, rapid growth and synchronous flowering characteristic of woody bamboos as large grasses. Our work provides insights into genome dominance in a remarkable polyploid system, including its dependence on genomic context and its ability to switch which subgenomes are dominant over evolutionary time.