arXiv subjects

Qingbo Wang

Publications and source records attributed to Qingbo Wang.

13 recordsLinked to original sources

arXiv2026

HiAER-Spike Software-Hardware Reconfigurable Platform for Event-Driven Neuromorphic Computing at Scale

In this work, we present HiAER-Spike, a modular, reconfigurable, event-driven neuromorphic computing platform designed to execute large spiking neural networks with up to 160 million neurons and 40 billion synapses - roughly twice the neurons of a mouse brain at faster than real time. This system, assembled at the UC San Diego Supercomputer Center, comprises a co-designed hard- and software stack that is optimized for run-time massively parallel processing and hierarchical address-event routing (HiAER) of spikes while promoting memory-efficient network storage and execution. The architecture efficiently handles both sparse connectivity and sparse activity for robust and low-latency event-driven inference for both edge and cloud computing. A Python programming interface to HiAER-Spike, agnostic to hardware-level detail, shields the user from complexity in the configuration and execution of general spiking neural networks with minimal constraints in topology. The system is made easily available over a web portal for use by the wider community. In the following, we provide an overview of the hard- and software stack, explain the underlying design principles, demonstrate some of the system's capabilities and solicit feedback from the broader neuromorphic community. Examples are shown demonstrating HiAER-Spike's capabilities for event-driven vision on benchmark CIFAR-10, DVS event-based gesture, MNIST, and Pong tasks.

cs.AR↗

arXiv2025

HiAER-Spike: Hardware-Software Co-Design for Large-Scale Reconfigurable Event-Driven Neuromorphic Computing

In this work, we present HiAER-Spike, a modular, reconfigurable, event-driven neuromorphic computing platform designed to execute large spiking neural networks with up to 160 million neurons and 40 billion synapses - roughly twice the neurons of a mouse brain at faster-than real-time. This system, which is currently under construction at the UC San Diego Supercomputing Center, comprises a co-designed hard- and software stack that is optimized for run-time massively parallel processing and hierarchical address-event routing (HiAER) of spikes while promoting memory-efficient network storage and execution. Our architecture efficiently handles both sparse connectivity and sparse activity for robust and low-latency event-driven inference for both edge and cloud computing. A Python programming interface to HiAER-Spike, agnostic to hardware-level detail, shields the user from complexity in the configuration and execution of general spiking neural networks with virtually no constraints in topology. The system is made easily available over a web portal for use by the wider community. In the following we provide an overview of the hard- and software stack, explain the underlying design principles, demonstrate some of the system's capabilities and solicit feedback from the broader neuromorphic community.

cs.NE↗

arXiv2023

Enhancing Secrecy Capacity in PLS Communication with NORAN based on Pilot Information Codebooks

In recent research, non-orthogonal artificial noise (NORAN) has been proposed as an alternative to orthogonal artificial noise (AN). However, NORAN introduces additional noise into the channel, which reduces the capacity of the legitimate channel (LC). At the same time, selecting a NORAN design with ideal security performance from a large number of design options is also a challenging problem. To address these two issues, a novel NORAN based on a pilot information codebook is proposed in this letter. The codebook associates different suboptimal NORANs with pilot information as the key under different channel state information (CSI). The receiver interrogates the codebook using the pilot information to obtain the NORAN that the transmitter will transmit in the next moment, in order to eliminate the NORAN when receiving information. Therefore, NORAN based on pilot information codebooks can improve the secrecy capacity (SC) of the communication system by directly using suboptimal NORAN design schemes without increasing the noise in the LC. Numerical simulations and analyses show that the introduction of NORAN with a novel design using pilot information codebooks significantly enhances the security and improves the SC of the communication system.

eess.SP↗

arXiv2022

Phase Difference based Doppler Disambiguation Method for TDM-MIMOFMCW Radars

State-of-the-art automotive radar sensors use a Mutliple-Input Mutiple-Output (MIMO) approach to obtain a better angular resolution. Time-Division Multiplexing (TDM) scheme is commonly applied to realize the orthogonality in time at the transmitter. Apart from its simplicity in implementation, TDM scheme has the drawback of a reduced maximum unambiguous Doppler proportional to the number of transmitters. In this paper, a phase difference based Doppler disambiguation method is proposed to regain the maximum unambiguous Doppler which is equivalent to only one transmitter. This method works well when the number of transmitters is large. The proposed method is demonstrated with simulation and measurement data.

eess.SP↗

arXiv2021

Dynamics of rotating spin-orbit-coupled Bose-Einstein condensates in a quasicrystalline optical lattice

We investigate the dynamics of rotating pseudo-spin-1/2 Bose-Einstein condensates (BECs) with Rashba spin-orbit coupling (SOC) in a quasicrystalline optical lattice (QOL). For given parameters, the system evolves from an initial heliciform-stripe phase into a final visible vortex necklace with a giant vortex and a hidden vortex necklace. Simultaneously, the corresponding spin texture undergoes a transition from a meron-antimeron pair to a half-antiskyrmion necklace. During the dynamic evolution process, the angular momentum increases gradually, and then approaches to a convergent value. Furthermore, typical quantum phases of rotating two-component BECs with SOC in different external potentials are summarized.

cond-mat.quant-gas↗

arXiv2021

Dynamics of kicked spin-orbit-coupled Bose-Einstein condensates

We investigate the dynamics of kicked pseudo-spin-1/2 Bose-Einstein condensates (BECs) with spin-orbit coupling (SOC) in a tightly confined toroidal trap. The system exhibits different dynamical behaviors depending on the competition among SOC, kick strength, kick period and interatomic interaction. For weak kick strength, with the increase of SOC the density profiles of two components evolve from overlapped symmetric distributions into staggered antisymmetric distributions, and the evolution of energy experiences a transition from quasiperiodic motion to modulated quantum beating. For large kick strength, when the SOC strength increases, the overlapped symmetric density distributions become staggered irregular patterns, and the energy evolution undergoes a transition from quasiperiodic motion to dynamical localization. Furthermore, in the case of weak SOC, the increase of kick period leads to a transition of the system from quantum beating to Rabi oscillation, while for the case of strong SOC the system demonstrates complex quasiperiodic motion.

cond-mat.quant-gas↗

arXiv2020

Topological defects in rotating spin-orbit-coupled dipolar spin-1 Bose-Einstein condensates

We consider the topological defects and spin structures of spin-1 Bose-Einstein condensates (BECs) with spin-orbit coupling (SOC) and dipole-dipole interaction (DDI) in a rotating harmonic plus quartic trap. The combined effects of SOC, DDI and rotation on the ground-state phases of the system are analyzed. Our results show that for fixed rotation frequency structural phase transitions can be achieved by adjusting the magnitudes of the SOC and DDI. A ground-state phase diagram is given as a function of the SOC and DDI strengths. It is shown that the system exhibits rich quantum phases including vortex string phase with isolated density peaks (DPs), triangular (square) vortex lattice phase with DPs, checkerboard phase, and stripe phase with hidden vortices and antivortices. For given SOC and DDI strengths, the system can display pentagonal vortex lattice with DPs, vortex necklace with DPs, and exotic topological structure composed of multi-layer visible vortex necklaces, a hidden giant vortex and hidden vortex necklaces, depending on the rotation frequency. In addition, the system sustains fascinating novel spin textures and skyrmion excitations, such as an antiskyrmion pair, antiskyrmion-half-antiskyrmion (antiskyrmion-antimeron) cluster, skyrmion-antiskyrmion lattice, skyrmion-antiskyrmion cluster, skyrmion-antiskyrmion-meron-antimeron lattice, double-layer half-antiskyrmion necklaces, and composite giant-antiskyrmion-antimeron necklaces.

cond-mat.quant-gas↗

arXiv2019

Topological defects of spin-orbit coupled Bose-Einstein condensates in a rotating anharmonic trap

We investigate the topological defects and spin structures of binary Bose-Einstein condensates (BECs) with Dresselhaus spin-orbit coupling (D-SOC) in a rotating anharmonic trap. Our results show that for initially mixed BECs without SOC the increasing rotation frequency can lead to the structural phase transition of the system. In the presence of isotropic D-SOC, the system sustains vortex pair,Anderson--Toulouse coreless vortices, circular vortex sheets, and combined vortex structures. In particular, when the rotation frequency is fixed above the radial trapping frequency the strong D-SOC results in a peculiar topological structure which is comprised of multi-layer visible vortex necklaces, hidden vortex necklaces and a hidden giant vortex. In addition, the system exhibits rich spin textures including basic skyrmion, meron cluster, skyrmion string and various skyrmion lattices. The skyrmions will be destroyed in the limit of large D-SOC or rotation frequency. Furthermore, the effects of anisotropic D-SOC and Rashba-Dresselhaus SOC on the topological structures of the system are discussed.

cond-mat.quant-gas↗

arXiv2019

Ground-state properties of spin-orbit-coupled dipolar Bose-Einstein condensates with in-plane gradient magnetic field

We investigate the ground-state properties of spin-orbit-coupled pseudo-spin-1/2 dipolar Bose-Einstein condensates (BECs) in a two-dimensional harmonic trap and an in-plane quadrupole field. The effects of spin-orbit coupling (SOC), dipole-dipole interaction (DDI) and the in-plane quadrupole field on the ground-state structures and spin textures of the system are systematically analyzed and discussed. For fixed SOC and DDI strengths, the system shows a quadrupole stripe phase with a half-quantum vortex, or a quadrupole Thomas-Fermi phase with a half-quantum antivortex for small quadrupole field strength, depending on the ratio between inter- and intraspecies interaction. As the quadrupole field strength enhances, the system realizes a ring mixed phase with a hidden vortex-antivortex cluster rather than an ordinary giant vortex in each component. Of particular interest, when the strengths of DDI and quadrupole field are fixed, strong SOC leads to the formation of criss-crossed vortex string structure. For given SOC and quadrupole field, the system for strong DDI displays a sandwich-like structure, or a special delaminated structure with a prolate antivortex in the spin-up component. In addition, typical spin textures for the ground states of the system are analyzed. It is shown that the system sustains exotic topological structures, such as a hyperbolic spin domain wall, skyrmion-half-antiskyrmion-antiskyrmion lattice, half-skyrmion-skyrmion-half-antiskyrmion lattice, and a drum-shaped antimeron.

cond-mat.quant-gas↗

arXiv2019

Topological excitations in rotating Bose-Einstein condensates with Rashba-Dresselhaus spin-orbit coupling in a two-dimensional optical lattice

We study the ground-state configurations and spin textures of rotating two-component Bose-Einstein condensates (BECs) with Rashba-Dresselhaus spin-orbit coupling (RD-SOC), which are confined in a two-dimensional (2D) optical lattice plus a 2D harmonic trap. In the absence of rotation, a relatively small isotropic 2D RD-SOC leads to the generation of ghost vortices for initially miscible BECs, while it gives rise to the creation of rectangular vortex-antivortex lattices for initially immiscible BECs. As the strength of the 2D RD-SOC enhances, the visible vortices or the 2D vortex-antivortex chains are created for the former case, whereas the rectangular vortex-antivortex lattices are transformed into vortex-antivortex rings for the later case. For the initially immiscible BECs with fixed 2D RD-SOC strength, the increase of rotation frequency can result in the structural phase transition from square vortex lattice to irregular triangular vortex lattice and the system transition from initial phase separation to phase mixing. In addition, we analyze the combined effects of 1D RD-SOC and rotation on the vortex configurations of the ground states for the case of initial phase separation. The increase of 1D SOC strength, rotation frequency or both of them may result in the formation of vortex chain and phase mixing. Furthermore, the typical spin textures for both the cases of 2D RD-SOC and 1D RD-SOC are discussed. It is shown that the system favors novel spin textures and skyrmion configurations including an exotic skyrmion-half-skyrmion lattice (skyrmion-meron lattice), a complicated meron lattice, a skyrmion chain, and a Bloch domain wall.

cond-mat.quant-gas↗

arXiv2019

Ground states of dipolar spin-orbit-coupled Bose-Einstein condensates in a toroidal trap

We investigate the ground-state structures of dipolar spin-orbit-coupled Bose-Einstein condensates in a toroidal trap. Combined effects of dipole-dipole interaction (DDI) and spin-orbit coupling (SOC) on the ground states of the system are discussed. A ground-state phase diagram is obtained as a function of the SOC and DDI strengths. As two new degrees of freedom, the DDI and SOC can be used to obtain the desired ground-state phases and to control the phase transition between various ground states. In particular, the system displays exotic topological structures and spin textures, such as half-quantum vortex, vortex string, vortex necklace, complex vortex lattice including giant vortex and hidden antivortex chains, different skyrmions, meron (half-skyrmion)-antimeron (half-antiskyrmion) necklace, and composite meron-antimeron lattice.

cond-mat.quant-gas↗

arXiv2009

Effect of Zn doping on magnetic order and superconductivity in LaFeAsO

We report Zn-doping effect in the parent and F-doped LaFeAsO oxy-arsenides. Slight Zn doping in LaFe$_{1-x}$Zn$_{x}$AsO drastically suppresses the resistivity anomaly around 150 K associated with the antiferromagnetic (AFM) spin density wave (SDW) in the parent compound. The measurements of magnetic susceptibility and thermopower confirm further the effect of Zn doping on AFM order. Meanwhile Zn doping does not affect or even enhances the $T_c$ of LaFe$_{1-x}$Zn$_{x}$AsO$_{0.9}$F$_{0.1}$, in contrast to the effect of Zn doping in high-$T_c$ cuprates. We found that the solubility of Zn content ($x$) is limited to less than 0.1 in both systems and further Zn doping (i.e., $x$ $\geq$ 0.1) causes phase separation. Our study clearly indicates that the non-magnetic impurity of Zn$^{2+}$ ions doped in the Fe$_2$As$_2$ layers affects selectively the AFM order, and superconductivity remains robust against the Zn doping in the F-doped superconductors.

cond-mat.supr-con↗

arXiv2008

Retinal oscillations carry visual information to cortex

Thalamic relay cells fire action potentials that transmit information from retina to cortex. The amount of information that spike trains encode is usually estimated from the precision of spike timing with respect to the stimulus. Sensory input, however, is only one factor that influences neural activity. For example, intrinsic dynamics, such as oscillations of networks of neurons, also modulate firing pattern. Here, we asked if retinal oscillations might help to convey information to neurons downstream. Specifically, we made whole-cell recordings from relay cells to reveal retinal inputs (EPSPs) and thalamic outputs (spikes) and analyzed these events with information theory. Our results show that thalamic spike trains operate as two multiplexed channels. One channel, which occupies a low frequency band (<30 Hz), is encoded by average firing rate with respect to the stimulus and carries information about local changes in the image over time. The other operates in the gamma frequency band (40-80 Hz) and is encoded by spike time relative to the retinal oscillations. Because these oscillations involve extensive areas of the retina, it is likely that the second channel transmits information about global features of the visual scene. At times, the second channel conveyed even more information than the first.

q-bio.NC↗