Classifying or predicting complex time-dependent signals is a challenging computational task. Reservoir computing (RC) is an efficient neuromorphic computing approach that is ideally suited to such tasks, and is typically implemented in software using a recurrent neural network (RNN) with fixed synaptic weights (the reservoir) connected to a single, trainable readout layer. However, more efficient implementations of RC are possible if the software RNN reservoir is substituted with a physical system with the correct properties, such as non-linear response to input signals and inherent memory [1].<br/>In this work, we exploit the chaotic and non-linear dynamics of a single magnetic domain wall (DW) trapped between two anti-notches in a Ni nanostrip as a hardware-based reservoir. We have modelled the structure (inset of Fig. 1) using both a simple 1D model and micromagnetic simulations with an oscillating field. As shown in Fig. 1, complex oscillatory dynamics over a range of field amplitudes are observed. A chaotic and multi-period regime occurs between 0.4 kA/m and 1.2 kA/m and a non-linear regime at higher fields. Thus, the DW oscillator can be used to transform an input magnetic field to the DW position output suitable for RC.<br/>A time-multiplexed input signal is injected into the DW oscillator by modulating the applied field magnitude, and we show how this approach allows the device to perform classification tasks as a reservoir.First, we demonstrate how the scaling to convert input data into applied fields affects the classification accuracy of the sine or square wave task, showing that the best recognition rate is obtained at the edge of a chaotic regime of oscillation (Fig.2). We also demonstrate that the DW oscillator can perform complex tasks, such as spoken digit recognition, and that coupling multiple DWs together enhances the computational capabilities of the reservoir. Our work opens new avenues for research into neuromorphic computing using nanomagnetic hardware.

![](https://assets.underline.io/uploads/markdown_image/1/image/b1c2f88ba8e32e54699a48e2fafd9388.jpg)

Bifurcation plot showing the DW position once per cycle for a given applied field using the 1D model. Inset: Schematic of the system.

![](https://assets.underline.io/uploads/markdown_image/1/image/7c99dd1e515fbc149d6687d21ac4a5b5.jpg)

Classification accuracy of the Sine-Square task over a range of field centre (H0) and field width (ΔH) values.


Neuromorphic computation with a single magnetic domain wall

In the Northern Ionian Sea, the Calabrian Accretionary Wedge (CAW) is facing directly the subducting Apula plate, mainly made of Mesozoic to Tertiary Carbonate Platform (Del Ben et al., 2010; Volpi et al., 2017). This contribution illuminates the structures and stratigraphic relationships between the frontal part of the orogenic belt, the foredeep and adjacent Apulian foreland. A detailed seismic facies analysis of four multichannel seismic profiles has been carried out to define the tectonic-sedimentary evolution of the study area but without exploration wells not available for these deep offshore area. Seismic interpretation allows to identify four main structural domains: the highly tectonized CAW; the narrow foredeep basin filled by a Pliocene-Holocene subhorizontal succession laying above buried normal faults; the massive carbonate succession of the Apulian Platform showing reef and carbonate platform margin facies; the layered succession of the Apulian Platform characterized by ‘'intra-platform'’ facies in the easternmost portion of the area. Three main regional unconformities with characteristic relationships with structural trends were recognized: i) the Messinian unconformity, related to a regional and significant erosion associated to paleokarst processes on the exposed Mesozoic Apulian Platform, is cut by an array of normal faults in the Apulian foreland and by thrust in the accretionary wedge; ii) the angular and erosive middle Pliocene Unconformity truncates the Lower Pliocene reflectors and is affected by normal faults in the foreland and by compressive tectonics in the CAW; iii) a Jurassic/Cretaceous unconformity in the Apulian foreland is marked by Cretaceous reflectors onlapping the Jurassic carbonate platform. The CAW is characterized by compressive tectonics with several fore-thrusts forming a leading imbricate fan system nearby the orogenic front. The Mesozoic Apulian platform is affected by active extensional tectonics driven by flexural bending since Lower Pliocene (Volpi et al., 2017; Maesano et al., 2020), that probably reactivated old normal faults related to the Permian-Triassic rifting stage. The structural map shows that transpressive and positive inversion tectonics is a common deformational style in the central sector of the foreland, suggesting that the Apulia plate is already part of the Calabrian/Hellenic belt. According to these observations, the compressive tectonics affecting the Apula plate is interpreted as related to shortening processes of both the CAW and Hellenic wedge whose interference plays an important role in defining the tectonic-stratigraphic evolution of the Apula Plate in the Northern Ionian Sea.

The response of the Apula plate to the advancing Calabrian and Hellenic wedges (Northern Ionian Sea): implications for subduction processes and tectono-stratigraphic evolution

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Neuromorphic computation with a single magnetic domain wall

The response of the Apula plate to the advancing Calabrian and Hellenic wedges (Northern Ionian Sea): implications for subduction processes and tectono-stratigraphic evolution

Predicting avalanches in granular materials from 'vibrational' modes

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