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The ultrafast dynamics and interactions of electrons in molecules and solids have long remained hidden from direct observation. For some time now, it has been possible to study these quantum-physical processes—for example, during chemical reactions, the conversion of sunlight into electricity in solar cells and elementary processes in quantum computers—in real time with a temporal resolution of a few femtoseconds (quadrillionths of a second) using two-dimensional electronic spectroscopy (2DES).

However, this technique is highly complex. Consequently, it has only been employed by a handful of research groups worldwide to date. Now a German-Italian team led by Prof. Dr. Christoph Lienau from the University of Oldenburg has discovered a way to significantly simplify the experimental implementation of this procedure. “We hope that 2DES will go from being a methodology for experts to a tool that can be widely used,” explains Lienau.

Two doctoral students from Lienau’s Ultrafast Nano-Optics research group, Daniel Timmer and Daniel Lünemann, played a key role in the discovery of the new method. The team has now published a paper in Optica describing the procedure.

Physicists at the University of Cologne have taken an important step forward in the pursuit of topological quantum computing by demonstrating the first-ever observation of Crossed Andreev Reflection (CAR) in topological insulator (TI) nanowires.

This finding, published under the title “Long-range crossed Andreev reflection in topological insulator nanowires proximitized by a superconductor” in Nature Physics, deepens our understanding of superconducting effects in these materials, which is essential for realizing robust quantum bits (qubits) based on Majorana zero-modes in the TI platform—a major goal of the Cluster of Excellence Matter and Light for Quantum Computing (ML4Q).

Quantum computing promises to revolutionize information processing, but current qubit technologies struggle with maintaining stability and error correction. One of the most promising approaches to overcoming these limitations is the use of topological superconductors, which can host special quantum states called Majorana zero-modes.

Scientists at the Okinawa Institute of Science and Technology (OIST), the National Institute of Information and Communications Technology, and the University of Tokyo have found a mathematical connection between spatial navigation and language processing, creating a model called “Disentangled Successor Information” (DSI).

This model generates patterns that closely resemble the activity of actual brain cells involved in both spatial awareness (place cells and grid cells) and concept recognition (concept cells).

The DSI model shows that the hippocampus and entorhinal cortex— previously known primarily for —likely use comparable computational processes to handle both physical spaces and meaningful ideas or words. Using this shared framework, both types of information can be processed through similar mathematical computations, which could be achieved in the brain by partial activation of specific groups of neurons.

Mind Control: Past and Future https://www.hks.harvard.edu/sites/default/files/2025-01/24_Meier_02.pdf


On Jan. 28, 2024, Noland Arbaugh became the first person to receive a brain chip implant from Neuralink, the neurotechnology company owned by Elon Musk. The implant seemed to work: Arbaugh, who is paralyzed, learned to control a computer mouse with his mind and even to play online chess.

The device is part of a class of therapeutics, (BCIs), that show promise for helping people with disabilities control prosthetic limbs, operate a computer, or translate their thoughts directly into speech. Current use of the technology is limited, but with millions of global cases of spinal cord injuries, strokes, and other conditions, some estimates put the market for BCIs at around $400 billion in the U.S. alone.

A new discussion paper from the Carr Center for Human Rights welcomes the potential benefits but offers a note of caution drawn from the past, detailing unsettling parallels between an era of new therapies and one of America’s darkest chapters: experiments into psychological manipulation and mind control.

Researchers at the University of Twente, in collaboration with the City University of Hong Kong, have designed a cutting-edge programmable photonic chip in a thin-film lithium niobate platform, an important material in photonics. Published in Nature Communications, this work paves the way for next-generation high-performance radar and communication applications.

An important material is changing the way work, making them smaller, faster, and more efficient: thin-film lithium niobate (TFLN). It offers exceptional properties for how light and electrical signals can interact. This enables the seamless integration of key components—such as electro-optic modulators and signal processors—onto a single chip. As a result, can achieve unprecedented compactness, efficiency, and performance.

Researchers at the University of Twente have designed a TFLN-based integrated photonic chip, working in close collaboration with City University of Hong Kong, where the fabrication takes place. At the same time, these chips are also being fabricated locally in the MESA+ Nanolab.

3D integrated circuits promise smaller, faster devices with lower power consumption. Vertically stacked 3D integrated circuits also enable novel in-memory and in-sensor computing paradigms and incorporate functionally diverse materials, which can benefit many edge applications. There are several complementary approaches to 3D integration. For example, 3D heterogeneous integration involves stacking and interconnecting multiple chips, each potentially made from different materials or optimized for different functions, within a single package. On the other hand, 3D monolithic integration refers to fabricating layers of transistors sequentially on a single wafer, creating a more seamless and compact structure. This approach offers even greater density and performance benefits by reducing interlayer distances and improving signal integrity. Both techniques are crucial for advancing the next generation of high-performance, energy-efficient electronic devices and require interdisciplinary collaborations across materials science, electrical engineering, and semiconductor manufacturing.

In this Communications Engineering collection, we aim to drive research in the engineering side of 3D integration by bringing together the following topics of interest:

An artificial nerve that is based on a vertical n-type organic electrochemical transistor with a gradient-intermixed bicontinuous structure can operate at high frequencies and mimic basic conditioned reflex behaviour in animals.

Phase transitions, like water freezing into ice, are a familiar part of our world. But in quantum systems, they can behave even more dramatically, with quantum properties such as Heisenberg uncertainty playing a central role. Furthermore, spurious effects can cause the systems to lose, or dissipate, energy to the environment. When they happen, these “dissipative phase transitions” (DPTs) push quantum systems into new states.

There are different types or “orders” of DPTs. First-order DPTs are like flipping a switch, causing abrupt jumps between states. Second-order DPTs are smoother but still transformative, changing one of the system’s global features, known as symmetry, in subtle yet profound ways.

DPTs are key to understanding how quantum systems behave in non-equilibrium conditions, where arguments based on thermodynamics often fail to provide answers. Beyond pure curiosity, this has practical implications for building more robust quantum computers and sensors. For example, second-order DPTs could enhance quantum information storage, while first-order DPTs reveal important mechanisms of system stability and control.

However, as with much of quantum physics, this “language”—the interaction between spins—is extraordinarily complex. While it can be described mathematically, solving the equations exactly is nearly impossible, even for relatively simple chains of just a few spins. Not exactly ideal conditions for turning theory into reality…

A model becomes reality

Researchers at Empa’s nanotech@surfaces laboratory have now developed a method that allows many spins to “talk” to each other in a controlled manner – and that also enables the researchers to “listen” to them, i.e. to understand their interactions. Together with scientists from the International Iberian Nanotechnology Laboratory and the Technical University of Dresden, they were able to precisely create an archetypal chain of electron spins and measure its properties in detail. Their results have now been published in the renowned journal Nature Nanotechnology.

Scientists have now cracked this secret using computational simulations and lab experiments, paving the way for bioengineered silk with game-changing applications, from medical sutures to ultra-strong body armor.

Spiders Strengthen Their Silk with Stretching

When spiders spin their webs, they use their hind legs to pull silk from their spinnerets. This pulling action does more than just release the silk—it strengthens the fibers, making the web more durable.