Aurelia Butler

Researchers from the University of Basel and the NCCR SPIN have achieved the first controllable interaction between two hole spin qubits in a conventional silicon transistor. The breakthrough opens up the possibility of integrating millions of these qubits on a single chip using mature manufacturing processes.
The race to build a practical quantum computer is well underway. Researchers around the world are working on a huge variety of qubit technologies. So far, there is no consensus on what type of qubit is most suitable for maximizing the potential of quantum information science.
Qubits are the foundation of a quantum computer: they handle the processing, transfer and storage of data. To work correctly, they have to both reliably store and rapidly process information. The basis for rapid information processing is stable and fast interactions between a large number of qubits whose states can be reliably controlled from the outside.
For a quantum computer to be practical, millions of qubits must be accommodated on a single chip. The most advanced quantum computers today have only a few hundred qubits, meaning they can only perform calculations that are already possible (and often more efficient) on conventional computers..
Electrons and holes
To solve the problem of arranging and linking thousands of qubits, researchers at the University of Basel and the NCCR SPIN rely on a type of qubit that uses the spin (intrinsic angular momentum) of an electron or a hole. A hole is essentially a missing electron in a semiconductor. Both holes and electrons possess spin, which can adopt one of two states: up or down, analogous to 0 and 1 in classical bits. Compared to an electron spin, a hole spin has the advantage that it can be entirely electrically controlled without needing additional components like micromagnets on the chip.
As early as 2022, Basel physicists were able to show that the hole spins in an existing electronic device can be trapped and used as qubits. These “FinFETs” (fin field-effect transistors) are built into modern smartphones and are produced in widespread industrial processes. Now, a team led by Dr. Andreas Kuhlmann has succeeded for the first time in achieving a controllable interaction between two qubits within this setup.

Fast and precise controlled spin-flip
A quantum computer needs “quantum gates” to perform calculations. These represent operations that manipulate the qubits and couple them to each other. As the researchers report in the journal Nature Physics, they were able to couple two qubits and bring about a controlled flip of one of their spins, depending on the state of the other’s spin — known as a controlled spin-flip. “Hole spins allow us to create two-qubit gates that are both fast and high-fidelity. This principle now also makes it possible to couple a larger number of qubit pairs,” says Kuhlmann.
The coupling of two spin qubits is based on their exchange interaction, which occurs between two indistinguishable particles that interact with each other electrostatically. Surprisingly, the exchange energy of holes is not only electrically controllable, but strongly anisotropic. This is a consequence of spin-orbit coupling, which means that the spin state of a hole is influenced by its motion through space.
To describe this observation in a model, experimental and theoretical physicists at the University of Basel and the NCCR SPIN combined forces. “The anisotropy makes two-qubit gates possible without the usual trade-off between speed and fidelity,” Dr. Kuhlmann says in summary.
“Qubits based on hole spins not only leverage the tried-and-tested fabrication of silicon chips, they are also highly scalable and have proven to be fast and robust in experiments.” The study underscores that this approach has a strong chance in the race to develop a large-scale quantum computer. More

New research finds that, while an increasing number of minors are using virtual reality (VR) apps, not many parents recognize the extent of the security and privacy risks that are specific to VR technologies. The study also found that few parents are taking active steps to address those security and privacy issues, such as using parental controls built into the apps.
“In recent years we have seen an increase in the number of minors using VR apps that have social interaction elements, which increases security and privacy risks — such as unintended self-disclosures of sensitive personal information and surveillance of a user’s biometric data,” says Abhinaya S B, co-author of a paper on the work and a Ph.D. student at NC State.
“We wanted to see how much parents know about security and privacy risks associated with these VR apps, and what they are currently doing to address those risks,” Abhinaya says. “These findings will help us identify areas where parents, technology designers, and policymakers could do more to enhance children’s security and privacy.”
For the study, researchers conducted in-depth interviews with 20 parents who have children under the age of 18 at home who use VR apps. The interviews were designed to capture what sort of risks parents perceived regarding VR apps, what strategies the parents used to protect their children’s security and privacy in regard to VR apps, and which VR stakeholders the parents felt were responsible for protecting children who use the apps.
“We found that parents were primarily worried about physiological development issues,” Abhinaya says. “For example, some parents were worried about VR damaging children’s eyesight or children injuring themselves while using the apps.”
“There were also concerns that children would interact with people online who would be a bad influence on them,” says Anupam Das, co-author of the paper and an assistant professor of computer science at NC State. “In terms of privacy, there were concerns that children might reveal too much information about themselves to strangers online.”
“We found that parents did not seem too worried about data surveillance or data collection by the VR companies and app developers; they were more worried about risks of self-disclosure in social VR apps,” Abhinaya says.

“VR technologies capture a tremendous amount of data on user movement, which can be used to infer information ranging from a user’s height to medical conditions,” Das says.
“VR technologies also capture a user’s voice, and there are some concerns that voice recordings could be misused,” Das says. “For example, it’s possible that voice recordings might be manipulated with generative AI tools to create fake recordings. Only one parent was concerned about potential misuse of voice recordings.”
“To be clear, most parents were aware of the possibility of data surveillance, but the vast majority were not concerned about it,” Abhinaya says.
When it came to risk management strategies, the study found parents were having conversations with their children about being safe and not sharing personal information online. Many parents were also sharing VR accounts with their children, so that they could monitor their children’s VR app use.
However, very few parents were making use of parental controls that were built into the VR technologies.
“Most parents were aware that the controls existed, they just weren’t activating them,” Abhinaya says. “In some cases, parents felt their children were more tech-savvy than themselves, and wanted to give their kids autonomy regarding VR usage. This was particularly the case for teens. But in some cases, parents didn’t make use of the controls due to technical challenges.”
“In other words, some parents didn’t know how to properly activate the controls,” Das says. “There was also a desire for parental controls to incorporate additional features, such as a summary of what a child did while using a given app, who they interacted with, and so on.”

The study found that parents felt they had the primary responsibility for protecting their children against risks associated with VR use. However, the parents also felt that VR companies should incorporate usable parental controls to help parents reduce risks. In addition, parents felt policymakers should stay abreast of emerging technologies to create or modify laws and regulations that protect children online. Lastly, parents felt that schools have a role to play in teaching children how to navigate these new technologies safely.
“It is essential for parents to experience and understand VR before they let their children use it, to get a sense of the security and privacy risks VR may pose,” Das says. “However, while parents serve as the first line of defense for protecting children against these risks in VR, it is imperative for other stakeholders such as educators, developers, and policymakers to take proactive steps to ensure the comprehensive protection of children in VR environments.”
This work was supported in part by an award from Meta Research. More

A team of scientists from A*STAR’s Genome Institute of Singapore (GIS) and Bioinformatics Institute (BII) has developed a new AI software tool called “BANKSY” that automatically recognises the cell types present in a tissue, such as muscle cells, nerve cells and fat cells. Going a step beyond conventional AI tools which can group cells together into clusters if they contain similar molecules, BANKSY also considers how similar the cells’ surroundings in the tissue are. With BANKSY, researchers would be able to improve their understanding of tissue processes in diverse diseases quicker and more accurately, which can support the development of more effective diagnostics and treatments for cancer, neurological disorders and other diseases. This breakthrough research was published in the article “BANKSY unifies cell typing and tissue domain segmentation for scalable spatial omics data analysis” in Nature Genetics on 27 February 2024.
BANKSY is adept at identifying subtly distinct cell groups in spatial molecular profiles generated from tissue samples. Moreover, BANKSY addresses the distinct but related problem of demarcating functionally distinct anatomical regions in tissue sections. For instance, it can distinguish layered structures in the human forebrain.
Spatial molecular profiling (Spatial Omics) technologies are powerful microscopes that allow scientists to study tissues in great detail, by revealing the exact locations of individual biological molecules in cells, as well as the arrangement of cells in tissues. This helps them understand how cells come together in tissues to perform their normal physiological functions, and also how they behave (or misbehave) in diseases such as cancer, autism or infectious diseases such as COVID-19. This understanding is essential for more accurate diagnosis and tailored treatment of patients, as well as the discovery of new drugs.
BANKSY can help biologists interpret and extract insights from the latest Spatial Omics technologies that have emerged over the past few years. Versatile, accurate, fast and scalable, BANKSY stands out from existing methods at analysing both RNA and protein-based Spatial Omics data. Capable of handling large datasets of over two million cells, BANKSY is 10 to 1,000 times faster than competing methods that were tested, and two to 60 times more scalable. This means that the method can also be applied to other key data-processing steps, such as detecting and removing poor quality areas of the sample, and for merging samples taken from different patients for combined analysis.
BANKSY has been independently benchmarked and found to be the best-performing algorithm for spatial omics data by two independent studies, one of which concluded that BANKSY can be a powerful solution for the identification of domains. The other study tested six algorithms and selected BANKSY as the most accurate for their data analysis.
Dr Shyam Prabhakar, Senior Group Leader, Laboratory of Systems Biology and Data Analytics and Associate Director, Spatial and Single Cell Systems at A*STAR’s GIS, said, “We anticipate that BANKSY will be a game-changing tool that helps to unlock the potential of emerging Spatial Omics technologies. This will hopefully improve our understanding of tissue processes in diverse diseases, allowing us to develop more effective treatments for cancers, neurological disorders and many other pathologies.”
Professor Liu Jian Jun, Acting Executive Director at A*STAR’s GIS, said, “The work on BANKSY advances our strategy of combining high-throughput technologies with scalable, robust AI software for problem-solving and identifying the clues to what can make a difference in the lives of patients.”
Dr Iain Tan, Senior Consultant, Division of Medical Oncology at National Cancer Centre Singapore and Senior Clinician Scientist at A*STAR’s GIS Laboratory of Applied Cancer Genomics, said, “We are using BANKSY to identify the cells that help tumours grow and spread to other parts of the body — drugs targeting such cells could be a promising direction for cancer treatment.” More

In sports training, practice is the key, but being able to emulate the techniques of professional athletes can take a player’s performance to the next level. AI-based personalized sports coaching assistants can make this a reality by utilizing published datasets. With cameras and sensors strategically placed on the athlete’s body, these systems can track everything, including joint movement patterns, muscle activation levels, and gaze movements.
Using this data, personalized feedback is provided on player technique, along with improvement recommendations. Athletes can access this feedback anytime, and anywhere, making these systems versatile for athletes at all levels.
Now, in a study published in the journal Scientific Data on April 5, 2024, researchers led by Associate Professor SeungJun Kim from the Gwangju Institute of Science and Technology (GIST), South Korea, in collaboration with researchers from Massachusetts Institute of Technology (MIT), CSAIL, USA, have developed a MultiSenseBadminton dataset for AI-driven badminton training.
“Badminton could benefit from these various sensors, but there is a scarcity of comprehensive badminton action datasets for analysis and training feedback,” says Ph.D. candidate Minwoo Seong, the first author of the study.
Supported by the 2024 GIST-MIT project, this study took inspiration from MIT’s ActionSense project, which used wearable sensors to track everyday kitchen tasks such as peeling, slicing vegetables, and opening jars. Seong collaborated with MIT’s team, including MIT CSAIL postdoc researcher Joseph DelPreto and MIT CSAIL Director and MIT EECS Professor Daniela Rus and Wojciech Matusik. Together, they developed the MultiSenseBadminton dataset, capturing movements and physiological responses of badminton players. This dataset, shaped with insights from professional badminton coaches, aims to enhance the quality of forehand clear and backhand drive strokes. For this, the researchers collected 23 hours of swing motion data from 25 players with varying levels of training experience.
During the study, players were tasked with repeatedly executing forehand clear and backhand drive shots while sensors recorded their movements and responses. These included inertial measurement units (IMU) sensors to track joint movements, electromyography (EMG) sensors to monitor muscle signals, insole sensors for foot pressure, and a camera to record both body movements and shuttlecock positions. With a total of 7,763 data points collected, each swing was meticulously labeled based on stroke type, player’s skill level, shuttlecock landing position, impact location relative to the player, and sound upon impact. The dataset was then validated using a machine learning model, ensuring its suitability for training AI models to evaluate stroke quality and offer feedback.
“The MultiSenseBadminton dataset can be used to build AI-based education and training systems for racket sports players. By analyzing the disparities in motion and sensor data among different levels of players and creating AI-generated action trajectories, the dataset can be applied to personalized motion guides for each level of players,” says Seong.
The gathered data can enhance training through haptic vibration or electrical muscle stimulation, promoting better motion and refining swing techniques. Additionally, player tracking data, like that in the MultiSenseBadminton dataset, could fuel virtual reality games or training simulations, making sports training more accessible and affordable, potentially transforming how people exercise.
In the long run, the researchers speculate that this dataset could make sports training more accessible and affordable for a broader audience, promote overall well-being, and foster a healthier population. More

Researchers from the University of Portsmouth have unveiled a quantum sensing scheme that achieves the pinnacle of quantum sensitivity in measuring the transverse displacement between two interfering photons.
This new technique has the potential to enhance superresolution imaging techniques that already employ single-photon sources as probes for the localization and tracking of biological samples, such as single-molecule localization microscopy with quantum dots.
Traditionally, achieving ultra-high precision in nanoscopic techniques has been constrained by the limitations of standard imaging methods, such as the diffraction limit of cameras and highly magnifying objectives. However, this new quantum sensing scheme circumvents these obstacles, paving the way for unprecedented levels of precision.
At the heart of this innovation lies an interferometric technique that not only achieves unparalleled spatial precision, but also maintains its effectiveness regardless of the overlap between displaced photonic wave packets. The precision of this technique is only marginally reduced when dealing with photons differing in nonspatial degrees of freedom, marking a significant advancement in quantum-enhanced spatial sensitivity.
Study co-author Professor Vincenzo Tamma, Director of the Quantum Science and Technology Hub, said: “These results shed new light on the metrological power of two-photon spatial interference and can pave the way to new high-precision sensing techniques.
“Other potential applications for the research could be found in the development of quantum sensing techniques for high-precision refractometry and astrophysical bodies localisation, as well as high-precision multi-parameter sensing schemes, including 3D quantum localisation methods. More

A new study co-authored by Sophie Janicke-Bowles, associate professor in Chapman University’s School of Communication, sheds light on the role that new and traditional media play in promoting and affecting character development, emotions, prosocial behavior and well-being (aka happiness) in youth.
Her research and teaching focus on positive psychology, media and new communication technologies, and media and spirituality. The study, published April 13 in Society for Research in Child Development (SRCD), investigates how adolescents perceive and engage with digital communication, including connectedness, positive social comparison, authentic self-presentation, civil participation and self-control.
“This was such an amazing research study to be part of as we all are craving more nuanced answers on how digital technologies affect our children,” said Janicke-Bowles.
Janicke-Bowles’ research contributes to the understanding of digital flourishing (positive social media experiences) among adolescents, highlighting the importance of supportive parental mediation and digital skills in promoting positive digital engagement. Moving forward, interventions aimed at enhancing digital flourishing should consider the role of parental guidance and support in shaping adolescents’ online experiences. Adolescents who flourish in their digital communication over time are more likely to have parents who know their way around technology and who actively support their children to positively communicate online. For adolescents who digitally flourish less, their self-control over digital communication decreases. To increase digital flourishing, interventions can aim in assisting adolescents in their control over their digital communication and encourage parents to take an active role in their young adults’ digital communication.These findings underscore the significance of parental influence and support in fostering positive digital communication experiences among adolescents.
In addition to her recent research, Janicke-Bowles has a distinguished history of exploring the intersection of media and psychology. As a member of a research team from Florida State and Penn State universities, she received a $1.9 million grant from the John Templeton Foundation to investigate the impact of media content on self-transcendent emotions. Her academic journey, spanning from clinical and media psychology in Germany to mass communication in the United States, underscores her commitment to understanding the profound effects of media on human experiences. More

Research led by scientists at the Department of Energy’s Oak Ridge National Laboratory has demonstrated that small changes in the isotopic content of thin semiconductor materials can influence their optical and electronic properties, possibly opening the way to new and advanced designs with the semiconductors.
Partly because of semiconductors, electronic devices and systems become more advanced and sophisticated every day. That’s why for decades researchers have studied ways to improve semiconductor compounds to influence how they carry electrical current. One approach is to use isotopes to change the physical, chemical and technological properties of materials.
Isotopes are members of a family of an element that all have the same number of protons but different numbers of neutrons and thus different masses. Isotope engineering has traditionally focused on enhancing so-called bulk materials that have uniform properties in three dimensions, or 3D. But new research led by ORNL has advanced the frontier of isotope engineering where current is confined in two dimensions, or 2D, inside flat crystals and where a layer is only a few atoms thick. The 2D materials are promising because their ultrathin nature could allow for precise control over their electronic properties.
“We observed a surprising isotope effect in the optoelectronic properties of a single layer of molybdenum disulfide when we substituted a heavier isotope of molybdenum in the crystal, an effect that opens opportunities to engineer 2D optoelectronic devices for microelectronics, solar cells, photodetectors and even next-generation computing technologies,” said ORNL scientist Kai Xiao.
Yiling Yu, a member of Xiao’s research team, grew isotopically pure 2D crystals of atomically thin molybdenum disulfide using molybdenum atoms of different masses. Yu noticed small shifts in the color of light emitted by the crystals under photoexcitation, or stimulation by light.
“Unexpectedly, the light from the molybdenum disulfide with the heavier molybdenum atoms was shifted farther to the red end of the spectrum, which is opposite to the shift one would expect for bulk materials,” Xiao said. The red shift indicates a change in the electronic structure or optical properties of the material.
Xiao and the team, working with theorists Volodymyr Turkowski and Talat Rahman at the University of Central Florida, knew that the phonons, or crystal vibrations, must be scattering the excitons, or optical excitations, in unexpected ways in the confined dimensions of these ultrathin crystals. They discovered how this scattering shifts the optical bandgap to the red end of the light spectrum for heavier isotopes. “Optical bandgap” refers to the minimum amount of energy needed to make a material absorb or emit light. By adjusting the bandgap, researchers can make semiconductors absorb or emit different colors of light, and such tunability is essential for designing new devices.

ORNL’s Alex Puretzky described how different crystals grown on a substrate can show small shifts in emitted color caused by regional strain in the substrate. To prove the anomalous isotope effect and measure its magnitude to compare with theoretical predictions, Yu grew molybdenum disulfide crystals with two molybdenum isotopes in one crystal.
“Our work was unprecedented in that we synthesized a 2D material with two isotopes of the same element but with different masses, and we joined the isotopes laterally in a controlled and gradual manner in a single monolayer crystal,” Xiao said. “This enabled us to observe the intrinsic anomalous isotope effect on the optical properties in the 2D material without the interference caused by an inhomogeneous sample.”
The study demonstrated that even a small change of isotope masses in the atomically thin 2D semiconductor materials can influence optical and electronic properties — a finding that provides an important basis for continued research.
“Previously, the belief was that to make devices such as photovoltaics and photodetectors, we had to combine two different semiconductor materials to make junctions to trap excitons and separate their charges. But actually, we can use the same material and just change its isotopes to create isotopic junctions to trap the excitons,” Xiao said. “This research also tells us that through isotope engineering, we can tune the optical and electronic properties to design new applications.”
For future experiments, Xiao and the team plan to collaborate with the experts at the High Flux Isotope Reactor and the Isotope Science and Engineering Directorate at ORNL. These facilities can provide various highly enriched isotope precursors to grow different isotopically pure 2D materials. The team can then further investigate the isotope effect on spin properties for their application in spin electronics and quantum emission.
This work was supported by DOE’s Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division and was performed at the Center for Nanophase Materials Sciences, or CNMS, at ORNL, an Office of Science user facility. The CNMS supported the TOF-SIMS, STEM and optical spectroscopy measurements. More