Tootfinder

Learning-to-learn enables rapid learning with phase-change memory-based in-memory computing
Thomas Ortner, Horst Petschenig, Athanasios Vasilopoulos, Roland Renner, \v{S}pela Brglez, Thomas Limbacher, Enrique Pi\~nero, Alejandro Linares Barranco, Angeliki Pantazi, Robert Legenstein
https://arxiv.org/abs/2405.05141

Learning-to-learn enables rapid learning with phase-change memory-based in-memory computing
There is a growing demand for low-power, autonomously learning artificial intelligence (AI) systems that can be applied at the edge and rapidly adapt to the specific situation at deployment site. However, current AI models struggle in such scenarios, often requiring extensive fine-tuning, computational resources, and data. In contrast, humans can effortlessly adjust to new tasks by transferring knowledge from related ones. The concept of learning-to-learn (L2L) mimics this process and enables A…

Electric and magnetic waveguides in graphene: quantum and classical
David Barranco, \c{S}eng\"ul Kuru, Javier Negro
https://arxiv.org/abs/2404.16114 h…

Electric and magnetic waveguides in graphene: quantum and classical
Electric and magnetic waveguides are considered in planar Dirac materials like graphene as well as their classical version for relativistic particles of zero mass and electric charge. In order to solve the Dirac-Weyl equation analytically, we have assumed the displacement symmetry of the system along a direction. In these conditions we have examined the rest of symmetries relevant each type, magnetic or electric system, which will determine their similarities and differences. We have worked out…

Triboelectric Pixels as building blocks for microscale and large area integration of drop energy harvesters
Ali Ghaffarinejad, Xabier Garcia-Casas, Fernando Nunez-Galvez, Jorge Budagosky, Vanda Godinho, Carmen Lopez-Santos, Juan Ramon Sanchez-Valencia, Angel Barranco, Ana Borras
https://arxiv.org/abs/2405.02464

Triboelectric Pixels as building blocks for microscale and large area integration of drop energy harvesters
The ultimate step towards the exploitation of water as a clean and renewable energy source addresses the energies stored in the low frequencies of liquid flows, which demands flexible solutions to adapt to multiple scenarios, from raindrops to waves, including water moving in pipelines and microdevices. Thus, harvesting low-frequency flows is a young concept compared to solar and wind powers, where triboelectric nanogenerators have been revealed as the most promising relevant actors. However, d…

Resonant wavelengths of whispering gallery modes with a variable refractive index
L. Vel\'azquez-Ibarra, J. Barranco
https://arxiv.org/abs/2403.00589 h…

Resonant wavelengths of whispering gallery modes with a variable refractive index
In this work we compute the resonant wavelength of whispering gallery modes for bulk-fused silica microspheres including chromatic dispersion. This is done following two methods: by solving the exact characteristic equation and, on the other hand, by solving the nonlinear equations that result for a variable refractive index in the asymptotic approximations. Similar results with both methods are obtained with differences below $1\%$ . Nevertheless, important differences are found with respect t…

Geometric structures on the quaternionic unit ball and slice regular M\"obius transformations
Raul Quiroga-Barranco
https://arxiv.org/abs/2402.13175 h…

Geometric structures on the quaternionic unit ball and slice regular Möbius transformations
Building from ideas of hypercomplex analysis on the quaternionic unit ball, we introduce Hermitian, Riemannian and Kähler-like structures on the latter. These are built from the so-called regular Möbius transformations. Such geometric structures are shown to be natural generalizations of those from the complex setup. Our structures can be considered as more natural, from the analytic viewpoint, than the usual quaternionic hyperbolic geometry. Furthermore, our constructions provide solutions t…

Semantic segmentation for recognition of epileptiform patterns recorded via Microelectrode Arrays in vitro
Gabriel Galeote-Checa, Gabriella Panuccio, Angel Canal-Alonso, Teresa Serrano-Gotarredona, Bernabe Linares Barranco
https://arxiv.org/abs/2402.08099

Semantic segmentation for recognition of epileptiform patterns recorded via Microelectrode Arrays in vitro
Epilepsy is a prevalent neurological disorder that affects approximately 1% of the global population. Around 30-40% of patients do not respond to pharmacological treatment, leading to a significant negative impact on their quality of life. Closed-loop deep brain stimulation (DBS) is a promising treatment for individuals who do not respond to medical therapy. To achieve effective seizure control, algorithms play an important role in identifying relevant electrographic biomarkers from local field…

Toeplitz operators and group-moment coordinates for quasi-elliptic and quasi-hyperbolic symbols
Raul Quiroga-Barranco, Armando Sanchez-Nungaray
https://arxiv.org/abs/2404.14582

Toeplitz operators and group-moment coordinates for quasi-elliptic and quasi-hyperbolic symbols
For $\mathbb{B}^n$ the $n$-dimensional unit ball and $D_n$ its Siegel unbounded realization, we consider Toeplitz operators acting on weighted Bergman spaces with symbols invariant under the actions of the maximal Abelian subgroups of biholomorphisms $\mathbb{T}^n$ (quasi-elliptic) and $\mathbb{T}^n \times \mathbb{R}_+$ (quasi-hyperbolic). Using geometric symplectic tools (Hamiltonian actions and moment maps) we obtain simple diagonalizing spectral integral formulas for such kinds of operators.…

Fragmentation of the Giant Pairing Vibration in 14C induced by many-body processes
Francisco Barranco, Gregory Potel, Enrico Vigezzi
https://arxiv.org/abs/2402.14166

Fragmentation of the Giant Pairing Vibration in 14C induced by many-body processes
We present a theoretical framework for treating the full excitation spectrum of Jπ = 0+ pair addition modes, including the well-known low-lying and bound Pairing Vibration on par with the predicted Giant Pairing Vibration lying in the continuum. Our formalism includes the coupling to low-energy collective quadrupole modes of the core, in such a way that both single-particle self-energy effects and the pairing interaction induced by phonon exchange are accounted for. The theory is applied to th…

Geometric structures on the quaternionic unit ball and slice regular M\"obius transformations
Raul Quiroga-Barranco
https://arxiv.org/abs/2402.13175 h…

Geometric structures on the quaternionic unit ball and slice regular Möbius transformations
Building from ideas of hypercomplex analysis on the quaternionic unit ball, we introduce Hermitian, Riemannian and Kähler-like structures on the latter. These are built from the so-called regular Möbius transformations. Such geometric structures are shown to be natural generalizations of those from the complex setup. Our structures can be considered as more natural, from the analytic viewpoint, than the usual quaternionic hyperbolic geometry. Furthermore, our constructions provide solutions t…

Hardware-aware training of models with synaptic delays for digital event-driven neuromorphic processors
Alberto Patino-Saucedo, Roy Meijer, Amirreza Yousefzadeh, Manil-Dev Gomony, Federico Corradi, Paul Detteter, Laura Garrido-Regife, Bernabe Linares-Barranco, Manolis Sifalakis
https://arxiv.org/abs/2404.10597

Hardware-aware training of models with synaptic delays for digital event-driven neuromorphic processors
Configurable synaptic delays are a basic feature in many neuromorphic neural network hardware accelerators. However, they have been rarely used in model implementations, despite their promising impact on performance and efficiency in tasks that exhibit complex (temporal) dynamics, as it has been unclear how to optimize them. In this work, we propose a framework to train and deploy, in digital neuromorphic hardware, highly performing spiking neural network models (SNNs) where apart from the syna…

Highly stable photoluminescence in vacuum-processed halide perovskite core-shell 1D nanostructures
Javier Castillo-Seoane, Lidia Contreras-Bernal, T. Cristina Rojas, Juan P. Espinos, Andres-Felipe Castro-Mendez, Juan-P. Correa-Baena, Angel Barranco, Juan R. Sanchez-Valencia, Ana Borras
https://arxiv.org/abs/2402.19269

Highly stable photoluminescence in vacuum-processed halide perovskite core-shell 1D nanostructures
Hybrid organometal halide perovskites (HP) present exceptional optoelectronic properties, but their poor long-term stability is a major bottleneck for their commercialization. Herein, we present a solvent-free approach to growing single-crystal organic nanowires (ONW), nanoporous metal oxide scaffolds, and HP to form a core@multishell architecture. The synthetic procedure is carried out under mild vacuum conditions employing thermal evaporation for the metal-free phthalocyanine (H2Pc) nanowires…