313 research outputs found
Quantum materials for energy-efficient neuromorphic computing
Neuromorphic computing approaches become increasingly important as we address
future needs for efficiently processing massive amounts of data. The unique
attributes of quantum materials can help address these needs by enabling new
energy-efficient device concepts that implement neuromorphic ideas at the
hardware level. In particular, strong correlations give rise to highly
non-linear responses, such as conductive phase transitions that can be
harnessed for short and long-term plasticity. Similarly, magnetization dynamics
are strongly non-linear and can be utilized for data classification. This paper
discusses select examples of these approaches, and provides a perspective for
the current opportunities and challenges for assembling quantum-material-based
devices for neuromorphic functionalities into larger emergent complex network
systems
Unbiased Random Number Generation using Injection-Locked Spin-Torque Nano-Oscillators
Unbiased sources of true randomness are critical for the successful
deployment of stochastic unconventional computing schemes and encryption
applications in hardware. Leveraging nanoscale thermal magnetization
fluctuations provides an efficient and almost cost-free means of generating
truly random bitstreams, distinguishing them from predictable pseudo-random
sequences. However, existing approaches that aim to achieve randomness often
suffer from bias, leading to significant deviations from equal fractions of 0
and 1 in the bitstreams and compromising their inherent unpredictability. This
study presents a hardware approach that capitalizes on the intrinsic balance of
phase noise in an oscillator injection locked at twice its natural frequency,
leveraging the stability of this naturally balanced physical system. We
demonstrate the successful generation of unbiased and truly random bitstreams
through extensive experimentation. Our numerical simulations exhibit excellent
agreement with the experimental results, confirming the robustness and
viability of our approach.Comment: 13 pages, 8 figure
Designing large arrays of interacting spin-torque nano-oscillators for microwave information processing
Arrays of spin-torque nano-oscillators are promising for broadband microwave
signal detection and processing, as well as for neuromorphic computing. In many
of these applications, the oscillators should be engineered to have
equally-spaced frequencies and equal sensitivity to microwave inputs. Here we
design spin-torque nano-oscillator arrays with these rules and estimate their
optimum size for a given sensitivity, as well as the frequency range that they
cover. For this purpose, we explore analytically and numerically conditions to
obtain vortex spin-torque nano-oscillators with equally-spaced gyrotropic
oscillation frequencies and having all similar synchronization bandwidths to
input microwave signals. We show that arrays of hundreds of oscillators
covering ranges of several hundred MHz can be built taking into account
nanofabrication constraints
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