The University of Tokyo · Physics and Astronomy
Professor Zhiqiang Liao's research lab specializes in nonlinear dynamics, spintronics, and stochastic computing, with a focus on leveraging physical phenomena such as magnetic relaxation, stochastic resonance, and noise-induced synchronization for advanced computing and sensing applications. The lab explores brain-inspired computing paradigms like reservoir computing and Ising machines, particularly through spintronic devices such as superparamagnetic tunnel junctions and spin glass materials, to achieve high-speed, low-power, and noise-robust information processing. A key research direction involves enhancing short-term memory and signal detection in nanoscale systems using non-Gaussian and colored noise, enabling robust logic operations and biomagnetic sensing.
Figures are computed from collected data and may differ slightly.
Reservoir computing is a brain heuristic computing paradigm that can complete training at a high speed. The learning performance of a reservoir computing system relies on its nonlinearity and short-term memory ability. As physical implementation, spintronic reservoir computing has attracted considerable attention because of its low power consumption and small size. However, few studies have focused on developing the short-term memory ability of the material itself in spintronics reservoir comput
A method of magnetocardiography (MCG) measurement using an overdamped bistable model based stochastic resonance (SR) technique for advancing biomagnetic sensors is proposed. To determine the system parameters for SR, an evolutionary algorithm combined with the coherent detection (CD) method is applied. We acquire and process an animal MCG at room temperature, detected by a commercially available optically pumped magnetometer. A comparison with a lowpass filter and the traditional CD method verif
Superparamagnetic tunnel junctions (SMTJs) are spintronic nanodevices that can oscillate spontaneously under the influence of thermal noise. Studies have proposed that SMTJs can be modeled as magnetic neurons by subjecting them to electrical Gaussian white noise and can be subsequently synchronized under subthreshold driving. Considering the non-Gaussian background noise in industrial applications, this study investigated the influence of levy noise on SMTJ subthreshold synchronization. The resu
Logical stochastic resonance (LSR) is a paradigm to realize reconfigurable robust Boolean operations using specific nonlinearity in the presence of background noise. The stable-state number of the traditional LSR is less than four, which restricts its upper limit in the heavy noise floor. To further improve the noise robustness and output quality of LSR, we proposed quadstable nonlinearity based LSR system for the first time in this work. Using the parameters determined by the ant lion optimizer
Abstract Gain‐dissipative Ising machines (GIMs) are a type of quantum analog equipment that can rapidly determine the optimal solution for combinatorial optimization problems. When the noise intensity is significantly lower than the fixed point of the system, the performance of a GIM is not influenced by the fluctuation of the noise intensity. However, the noise in this study is limited to Gaussian white noise. The influence of prevalent colored noise on GIMs has not been researched. In this stu
Abstract Gain-dissipative Ising machines (GIMs) are dedicated devices that can rapidly solve combinatorial optimization problems. The noise intensity in traditional GIMs should be significantly smaller than its saturated fixed-point amplitude, indicating a lower noise margin. To overcome the existing limit, this work proposes an overdamped bistability-based GIM (OBGIM). Numerical test on uncoupled spin network show that the OBGIM has a different bifurcation dynamics from that of the traditional
Detecting QRS waves with high sensitivity and precision in noisy electrocardiogram (ECG) recordings is crucial for cardiovascular disease monitoring. A main challenge is the in-band noise contamination that overlaps with the ECG signal spectrum, which is difficult to completely eliminate using traditional filtering methods. Inspired by solid-state physics, we propose a 1-D lattice potential (OLP)-based algorithm to enhance robustness against in-band noise. The algorithm first bandpass filtered t
Logical stochastic resonance (LSR) system is a physical system capable of performing robust reconfigurable logical operations in the presence of background noise using specific nonlinearities. Traditional LSR systems are typically based on polynomial nonlinearities, which make them suitable for implementation by electronic components. However, there has been little research on LSR systems based on hyperbolic nonlinearities which have the potential to be realized directly using the physical prope
Abstract Gain‐dissipative Ising machines (GIMs) are annealers inspired by physical systems such as Ising spin glasses to solve combinatorial optimization problems. Compared to traditional quantum annealers, GIM is relatively easier to scale and can save on additional power consumption caused by low‐temperature cooling. However, traditional GIMs have a limited noise margin. Specifically, their normal operation requires ensuring that the noise intensity is lower than their saturation fixed point a
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