New method to control electron spin paves the way for efficient quantum computers

Researchers at the University of Rochester developed a new method for manipulating information in quantum systems by controlling the spin of electrons in silicon quantum dots. Electrons in silicon experience a phenomenon called spin-valley coupling between their spin (up and down arrows) and valley states (blue and red orbitals). When researchers apply a voltage (blue glow) to electrons in silicon, they harness the spin-valley coupling effect and can manipulate the spin and valley states, controlling the electron spin.
Illustration Credit: Michael Osadciw / University of Rochester

The method, developed by Rochester scientists, overcomes the limitations of electron spin resonance.

Quantum science has the potential to revolutionize modern technology with more efficient computers, communication, and sensing devices. Challenges remain in achieving these technological goals, however, including how to precisely manipulate information in quantum systems.

In a paper published in Nature Physics, a group of researchers from the University of Rochester, including John Nichol, an associate professor of physics, outlines a new method for controlling electron spin in silicon quantum dots—tiny, nanoscale semiconductors with remarkable properties—as a way to manipulate information in a quantum system.

“The results of the study provide a promising new mechanism for coherent control of qubits based on electron spin in semiconductor quantum dots, which could pave the way for the development of a practical silicon-based quantum computer,” Nichol says.

The coupling of two quantum dots was successful for the first time

Arne Ludwig was responsible for the design and manufacture of the semiconductor structures for the experiment.
Photo Credit: RUB, Kramer

This means a big step towards the technical applicability of quantum technology, for example for arithmetic operations.

A tiny change means a big breakthrough in quantum physics: an international research team from Bochum and Copenhagen has managed to couple two quantum dots in one nanochip. After exciting a quantum point using a laser, a signal is sent out, the origin of which can no longer be related to one of the quantum points, as if both had each sent half of the signal in the form of a single photon. "At first that sounds like a little success, but this signal entanglement, which sits on a single photon, is more than the sum of its parts," says Dr. Arne Ludwig from the Chair of Solid-State Physics at the Ruhr University Bochum. “It represents a big step towards the usability of quantum technology for computer operations. "Together with researchers from the Niels Bohr Institute at the University of Copenhagen, the Bochum team published the results in the journal Science from 27. Published January 2023.

Machine learning identifies drugs that could potentially help smokers quit

Penn State College of Medicine researchers helped identify eight medications that may be repurposed to help people quit smoking. A team of more than 70 researchers contributed to the analysis of genetic and smoking behavior data from more than 1.3 million people.
Image Credit: Scientific Frontline

Medications like dextromethorphan, used to treat coughs caused by cold and flu, could potentially be repurposed to help people quit smoking cigarettes, according to a study by Penn State College of Medicine and University of Minnesota researchers. They developed a novel machine learning method, where computer programs analyze data sets for patterns and trends, to identify the drugs and said that some of them are already being tested in clinical trials.

Cigarette smoking is risk factor for cardiovascular disease, cancer and respiratory diseases and accounts for nearly half a million deaths in the United States each year. While smoking behaviors can be learned and unlearned, genetics also plays a role in a person’s risk for engaging in those behaviors. The researchers found in a prior study that people with certain genes are more likely to become addicted to tobacco.

Using genetic data from more than 1.3 million people, Dajiang Liu, Ph.D., professor of public health sciences, and of biochemistry and molecular biology and Bibo Jiang, Ph.D., assistant professor of public health sciences, co-led a large multi-institution study that used machine learning to study these large data sets — which include specific data about a person’s genetics and their self-reported smoking behaviors.

Targeting cancer with a multidrug nanoparticle

MIT chemists designed a bottlebrush-shaped nanoparticle that can be loaded with multiple drugs, in ratios that can be easily controlled.
Illustration Credit: Courtesy of the researchers. Edited by MIT News.

Treating cancer with combinations of drugs can be more effective than using a single drug. However, figuring out the optimal combination of drugs, and making sure that all of the drugs reach the right place, can be challenging.

To help address those challenges, MIT chemists have designed a bottlebrush-shaped nanoparticle that can be loaded with multiple drugs, in ratios that can be easily controlled. Using these particles, the researchers were able to calculate and then deliver the optimal ratio of three cancer drugs used to treat multiple myeloma.

“There’s a lot of interest in finding synergistic combination therapies for cancer, meaning that they leverage some underlying mechanism of the cancer cell that allows them to kill more effectively, but oftentimes we don’t know what that right ratio will be,” says Jeremiah Johnson, an MIT professor of chemistry and one of the senior authors of the study.

A study on the rotation of the Earth’s solid core confuses the mainstream media. Scientists of the Royal Observatory of Belgium clarify it

Earth Structure
Illustration Credit: Courtesy of Royal Observatory of Belgium

An article in Nature Geoscience on the rotation of the Earth’s core (more precisely its solid inner core) was recently published. However, the media have been misled by the press release of the science journal into thinking that the inner core stopped rotating or was even rotating in the opposite direction to that of the Earth surface, which is not the case at all. Scientists of the Royal Observatory of Belgium specialized in the rotation of the Earth and planets clarify the study and provide some information on the structure and rotation of the Earth.

Internal structure and rotation of the Earth

The interior of the Earth is divided into concentric layers. A few tens of kilometers below the surface begins the solid mantle, which extends to a depth of about 2900 km. Below that is the Earth’s core, which consists mainly of iron. The core is subdivided into an upper liquid layer down to a depth of about 5150 km and a central solid inner core with a radius of about 1220 km. The article in Nature Geoscience article is about the solid inner core.

The Earth revolves around its axis of rotation in 24 hours. Movements in the Earth’s atmosphere, hydrosphere and liquid core can cause small variations in the rotational period, so-called “length-of-day variations”, which can be on the order of milliseconds. The different layers that make up the Earth are linked by gravity and the frictional force and the electromagnetic force between the core and the solid parts. Therefore, the rotational period of the solid inner core can show small variations compared to the rotation of the mantle.

UNSW eco-friendly aviation research project receives CRC-P funding

Dr Branislav Hredzak and Professor John Fletcher have been awarded funding from Round 13 of the CRC Project scheme in collaboration with Dovetail Electric Aviation
Photo Credit: Dovetail Electric Aviation

An innovative UNSW research and development project focused on making regional commuter services greener and cheaper has been awarded a CRC-P grant.

Two UNSW Sydney researchers in collaboration with industry partners have been awarded $3 million in funding from the federal government’s Cooperative Research Centre Projects (CRC-P) program. This is part of a $12.8 million project that will convert a turboprop plane to electric propulsion, providing regional commuter services.

UNSW Senior Lecturer Dr Branislav Hredzak and Professor John Fletcher at the School of Electrical Engineering and Telecommunications secured the funding from Round 13 of the CRC Project scheme, for the project 'Electric Conversion to Fast Track Zero Emissions Commercial Aviation', together with Dovetail Electric Aviation, Sydney Seaplanes, Memko Aviation, Aerospace and Defense and CSIRO.

The project will develop, flight test and certify the conversion to electric propulsion of a turboprop aircraft, which will make regional commuter services eco-friendlier and more affordable with a focus on emissions-free aircraft for use on regional routes in the future.

Farming more seaweed for food, feed and fuel

Seaweed farmers in East Nusa Tenggara, Indonesia
Photo Credit: Eldo Rafael

A University of Queensland-led study has shown that expanding global seaweed farming could go a long way to addressing the planet’s food security, biodiversity loss and climate change challenges.

PhD Candidate Scott Spillias, from UQ’s School of Earth and Environmental Science, said seaweed offered a sustainable alternative to land-based agricultural expansion to meet the world’s growing need for food and materials.

“Seaweed has great commercial and environmental potential as a nutritious food and a building block for commercial products including animal feed, plastics, fibers, diesel and ethanol,” Mr. Spillias said.

“Our study found that expanding seaweed farming could help reduce demand for terrestrial crops and reduce global agricultural greenhouse gas emissions (GHG) by up to 2.6 billion tons of CO2-equivalent per year.”

Researchers mapped the potential of farming more of the 34 commercially important seaweed species using the Global Biosphere Management Model.

Kill Dates for Re-Exposed Black Mosses

Cape Rasmussen, one of the study sites mentioned in the paper.
Photo Credit: Derek J. Ford.

In their new paper for the Geological Society of America journal Geology, Dulcinea Groff and colleagues used radiocarbon ages (kill dates) of previously ice-entombed dead black mosses to reveal that glaciers advanced during three distinct phases in the northern Antarctic Peninsula over the past 1,500 years.

The terrestrial cryosphere and biosphere of the Antarctic Peninsula are changing rapidly as “first responders” to polar warming. We know from other studies that large glaciers of the Antarctic Peninsula are responding quickly to warmer summer air temperatures, and scientists have modeled that the glaciers expanded in the past because of cooler temperatures, and not increased precipitation. However, we know much less about how this plays out at sea level where ice, ocean, and sensitive coastal life interact. Knowing when glaciers advanced and retreated in the past would improve our understanding of biodiverse coastal ecosystems—thriving with seals, penguins, and plants—and their sensitivity in the Antarctic Peninsula. One of the limitations of reconstructing glacier history is that there are not that many types of terrestrial archives we can use to constrain past glacier behavior. Re-exposed dead plants, abandoned penguin colonies, and rocks can be dated to better know the timing of permanent snow or glacier advance in the past.

Rapid plant evolution may make coastal regions more susceptible to flooding and sea level rise

Brady Stiller, University of Notre Dame
Photo Credit: Courtesy University of Notre Dame

Evolution has occurred more rapidly than previously thought in the Chesapeake Bay wetlands, which may decrease the chance that coastal marshes can withstand future sea level rise, researchers at the University of Notre Dame and collaborators demonstrated in a recent publication in Science.

 Jason McLachlan, an associate professor in the Department of Biological Sciences, evaluated the role evolution plays in ecosystems in the Chesapeake Bay by studying a type of grass-like plant, Schoenoplectus americanus, also called chairmaker’s bulrush. The research team used a combination of historical seeds found in core sediment samples, modern plants, and computational models to demonstrate that “resurrected” plants were allocating more resources in their roots below ground, allowing them to store carbon more quickly than modern plants.

New virus discovered in whales, dolphins across the Pacific

Photo Credit: Richard Sagredo

A novel virus, potentially fatal to whales and dolphins, has been discovered by researchers at the University of Hawaiʻi Health and Stranding Lab. Prior to its discovery in 10 whale and dolphin host species across the Pacific, the virus was found in only a single marine mammal worldwide, a Longman’s beaked whale stranded on Maui in 2010. The findings were published in Frontiers in Marine Science.

The discovery of beaked whale circovirus (BWCV) in whales and dolphins expands the knowledge of marine mammal species that can become infected with the disease. Circoviruses are DNA viruses that cause disease in birds, pigs and dogs, and in severe cases can become fatal.

“Our study found Cuvier’s beaked whales tested positive for BWCV in Saipan and American Samoa, nearly 4,000 miles away from the first discovered case,” said Kristi West, director of the UH Health and Stranding Lab. “The positive cases found outside of Hawaiʻi were surprising, and indicates that this virus is spread across the Central and Western Pacific and may have a global presence in marine mammals.”