Wuhan Engineering Science & Technology Institute

Abstract In this study, we report on a detailed polarimetric single-pulse analysis of the radio emission from the pulsar B0823+26 (J0825+2637) during its quiescent state. Using the unprecedentedly high-sensitive observations carried out with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) at 1250 MHz, potentially interesting emission features are revealed, distinct from bright-state characteristics. The interpulse emission is completely absent, with only the main pulse and postcursor components detected. Notably, no bridging emission is observed between these two distinct emission components. Both the main pulse and postcursor exhibit continuous emission without any pulse nulling phenomenon throughout the observation period. During the nearly 3 hr continuous observation period, a total of 571 bright pulses with relative pulse energy larger than 10 are detected within the main pulse window. Their energy distribution follows a power-law distribution with an index of −2.39 ± 0.03. The interburst time distribution is consistent with a stationary Poisson process, yielding a burst rate of 158 ± 8 events per hour. Furthermore, the fluctuation spectral analysis of single pulse behavior reveals the existence of a periodic amplitude modulation of longitude-stationary subpulses with a periodicity of 20 ± 7 rotational periods across the main pulse window. Possible emission mechanisms are discussed.

Abstract The rapid progress of artificial intelligence has exposed the inherent limitations of the conventional chip technology, particularly the high energy-consumption, driving the emergence of neuromorphic chips and ionics. Using K + ion-filled graphene channels, we investigate the mechanism underlying the graphene-based ion transistors by ab initio molecular dynamics simulations. Here we show that graphene electrons enable long-range correlation of confined ions, which provides a basis for the sensitive responses of transistors to the channel ion density (as modulated by a gate voltage). The ON/OFF switching effect specifically results from the competition between π-π stacking and cation-π interaction in the channels with different ion-filling densities. The nonlinear increasing of transport efficiency (i.e., signal amplification effect) is due to the ion density-depended collective oscillation of channel-confined ions. Additionally, resonance between channel-outside and channel-confined ions triggers rapid ion dehydration, enabling the transistor’s ultrahigh ion diffusivity. These atomic-level insights as a design principle for the ultralow energy-consumption neuro-morphic chips.