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Jun 27, 2024

Fundamental spatial limits of all-optical magnetization switching

Posted by in categories: computing, nanotechnology

Magnetization can be switched with a single laser pulse. However, it is not known whether the underlying microscopic process is scalable to the nanometer length scale, a prerequisite for making this technology competitive for future data storage applications. Researchers at the Max Born Institute in Berlin, Germany, in collaboration with colleagues at the Instituto de Ciencia de Materiales in Madrid, Spain, and the free-electron laser facility FERMI in Trieste, Italy, have determined a fundamental spatial limit for light-driven magnetization reversal.

They report their finsings in Nano Letters (“Exploring the Fundamental Spatial Limits of Magnetic All-Optical Switching”).

Modern magnetic hard drives can store more than one terabit of data per square inch, which means that the smallest unit of information can be encoded on an area smaller than 25 nanometers by 25 nanometers. In laser-based, all-optical switching (AOS), magnetically encoded bits are switched between their “0” and “1” state with a single ultrashort laser pulse. To realize the full potential of AOS, particularly in terms of faster write/erase cycles and improved power efficiency, we thus need to understand whether a magnetic bit can still be all-optically reversed if its size is on the nanoscale.

Jun 27, 2024

Advances in the study of the structure that is formed around gold nanoparticles

Posted by in categories: biotech/medical, nanotechnology

Gold nanoparticles have been the subject of intense research for several decades due to their interesting applications in fields such as catalysis and medicine. “Surface ligands” are organic molecules typically present on the surface of gold nanoparticles. During synthesis, these surface ligands play an important role in controlling the size and shape of the nanoparticles.

For several decades, the CIC biomaGUNE team led by Ikerbasque Research Professor Luis Liz-Marzán has studied in detail the growth mechanisms and properties of these nanoparticles. Despite numerous advances that have recognized the importance of surface ligands, many questions remain about their exact behavior during and after growth. Direct observation of surface ligands and their interface with gold nanoparticles has therefore been a long-standing goal for many scientists in this field.

Transmission Electron Microscopy (TEM) is the technique most widely used to investigate nanoparticles. However, the study of surface ligands by means of TEM presents significant challenges; the reason is that the ligands are sensitive to the electron beam, their contrast is limited and their structure in vacuum differs from their native state in solution.

Jun 27, 2024

New work explores optimal circumstances for reaching a common goal with humanoid robots

Posted by in category: robotics/AI

Researchers at the Istituto Italiano di Tecnologia (IIT-Italian Institute of Technology) have demonstrated that under specific conditions, humans can treat robots as co-authors of the results of their actions. The condition that enables this phenomenon is that a robot behaves in a human-like, social manner. Engaging in gaze contact and participating in a common emotional experience, such as watching a movie, are the key.

The study was published in Science Robotics and paves the way for understanding and designing the optimal circumstances for humans and robots to collaborate in the same environment.

Continue reading “New work explores optimal circumstances for reaching a common goal with humanoid robots” »

Jun 27, 2024

Engineers Discovered the Spectacular Secret to Making 17x Stronger Cement

Posted by in category: innovation

The breakthrough could lead to more durable—and drastically safer—buildings.

Jun 27, 2024

Mechanical computer relies on kirigami cubes, not electronics

Posted by in categories: computing, engineering

North Carolina State University researchers have developed a kirigami-inspired mechanical computer that uses a complex structure of rigid, interconnected polymer cubes to store, retrieve and erase data without relying on electronic components. The system also includes a reversible feature that allows users to control when data editing is permitted and when data should be locked in place.

Mechanical computers are computers that operate using rather than electronic ones. Historically, these mechanical components have been things like levers or gears. However, mechanical computers can also be made using structures that are multistable, meaning they have more than one stable state—think of anything that can be folded into more than one stable position.

“We were interested in doing a couple things here,” says Jie Yin, co-corresponding author of a paper on the work and an associate professor of mechanical and aerospace engineering at NC State. “First, we were interested in developing a stable, for storing data.

Jun 27, 2024

Is consciousness really a problem?

Posted by in categories: education, neuroscience

The Journal of Consciousness Studies has an issue out on the meta-problem of consciousness. (Unfortunately, it’s paywalled, so you’ll need a subscription, or access to a school network that has one.)

As a reminder, there’s the hard problem of consciousness, coined by David Chalmers in 1995, which is the question of why or how we have conscious experience, or as described by others, how conscious experience “arises” from physical systems.

Then there’s the meta-problem, also more recently coined by Chalmers, on why we think there is a hard problem. The meta-problem is an issue long identified by people in the illusionist camp, those who see phenomenal consciousness as an illusion, a mistaken concept.

Jun 27, 2024

The prospects for a scientific understanding of consciousness

Posted by in category: neuroscience

Michael Shermer has an article up at Scientific American asking if science will ever understand consciousness, free will, or God.

I contend that not only consciousness but also free will and God are mysterian problems—not because we are not yet smart enough to solve them but because they can never be solved, not even in principle, relating to how the concepts are conceived in language.

On consciousness in particular, I did a post a few years ago which, on the face of it, seems to take the opposite position. However, in that post, I made clear that I wasn’t talking about the hard problem of consciousness, which is what Shermer addresses in his article. Just to recap, the “hard problem of consciousness” was a phrase originally coined by philosopher David Chalmers, although it expressed a sentiment that has troubled philosophers for centuries.

Jun 27, 2024

Sentience and the Origins of Consciousness: From Cartesian Duality to Markovian Monism

Posted by in categories: evolution, mathematics, neuroscience, physics

This essay addresses Cartesian duality and how its implicit dialectic might be repaired using physics and information theory. Our agenda is to describe a key distinction in the physical sciences that may provide a foundation for the distinction between mind and matter, and between sentient and intentional systems. From this perspective, it becomes tenable to talk about the physics of sentience and ‘forces’ that underwrite our beliefs (in the sense of probability distributions represented by our internal states), which may ground our mental states and consciousness. We will refer to this view as Markovian monism, which entails two claims: fundamentally, there is only one type of thing and only one type of irreducible property (hence monism). All systems possessing a Markov blanket have properties that are relevant for understanding the mind and consciousness: if such systems have mental properties, then they have them partly by virtue of possessing a Markov blanket (hence Markovian). Markovian monism rests upon the information geometry of random dynamic systems. In brief, the information geometry induced in any system—whose internal states can be distinguished from external states—must acquire a dual aspect. This dual aspect concerns the (intrinsic) information geometry of the probabilistic evolution of internal states and a separate (extrinsic) information geometry of probabilistic beliefs about external states that are parameterised by internal states. We call these intrinsic (i.e., mechanical, or state-based) and extrinsic (i.e., Markovian, or belief-based) information geometries, respectively. Although these mathematical notions may sound complicated, they are fairly straightforward to handle, and may offer a means through which to frame the origins of consciousness.

Keywords: consciousness, information geometry, Markovian monism.

Jun 27, 2024

Defending eliminative structuralism and a whole lot more (or less)

Posted by in categories: mathematics, particle physics

Ontic structural realism argues that structure is all there is. In (French, 2014) I argued for an ‘eliminativist’ version of this view, according to which the world should be conceived, metaphysically, as structure, and objects, at both the fundamental and ‘everyday’ levels, should be eliminated. This paper is a response to a number of profound concerns that have been raised, such as how we might distinguish between the kind of structure invoked by this view and mathematical structure in general, how we should choose between eliminativist ontic structural realism and alternative metaphysical accounts such as dispositionalism, and how we should capture, in metaphysical terms, the relationship between structures and particles. In developing my response I shall touch on a number of broad issues, including the applicability of mathematics, the nature of representation and the relationship between metaphysics and science in general.

Keywords: Causation; Dependence; Disposition; Metaphysics; Object; Representation; Structure.

Copyright © 2018. Published by Elsevier Ltd.

Jun 27, 2024

Multilevel development of cognitive abilities in an artificial neural network

Posted by in category: robotics/AI

Several neuronal mechanisms have been proposed to account for the formation of cognitive abilities through postnatal interactions with the physical and sociocultural environment. Here, we introduce a three-level computational model of information processing and acquisition of cognitive abilities. We propose minimal architectural requirements to build these levels, and how the parameters affect their performance and relationships. The first sensorimotor level handles local nonconscious processing, here during a visual classification task. The second level or cognitive level globally integrates the information from multiple local processors via long-ranged connections and synthesizes it in a global, but still nonconscious, manner. The third and cognitively highest level handles the information globally and consciously. It is based on the global neuronal workspace (GNW) theory and is referred to as the conscious level. We use the trace and delay conditioning tasks to, respectively, challenge the second and third levels. Results first highlight the necessity of epigenesis through the selection and stabilization of synapses at both local and global scales to allow the network to solve the first two tasks. At the global scale, dopamine appears necessary to properly provide credit assignment despite the temporal delay between perception and reward. At the third level, the presence of interneurons becomes necessary to maintain a self-sustained representation within the GNW in the absence of sensory input. Finally, while balanced spontaneous intrinsic activity facilitates epigenesis at both local and global scales, the balanced excitatory/inhibitory ratio increases performance. We discuss the plausibility of the model in both neurodevelopmental and artificial intelligence terms.

Keywords: artificial consciousness; cognitive architecture; global neuronal workspace; synaptic epigenesis.

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