This startup’s tech outperforms cryo-CMOS devices in speed and efficiency.
Category: computing – Page 368
New Quantum Computer Algorithm Unlocks the Power of Atomic-Level Interactions
A novel protocol for quantum computers could reproduce the complex dynamics of quantum materials.
RIKEN researchers have created a hybrid quantum-computational algorithm that can efficiently calculate atomic-level interactions in complex materials. This innovation enables the use of smaller quantum computers or conventional ones to study condensed-matter physics and quantum chemistry, paving the way for new discoveries in these fields.
A quantum-computational algorithm that could be used to efficiently and accurately calculate atomic-level interactions in complex materials has been developed by RIKEN researchers. It has the potential to bring an unprecedented level of understanding to condensed-matter physics and quantum chemistry—an application of quantum computers first proposed by the brilliant physicist Richard Feynman in 1981.
Quantum Computers Could Be a ‘Superhighway’ to Experiencing Our Other Selves in the Multiverse
It could be a strange way of achieving immortality—or at least, everlasting life for copies of you.
Quantum Spin Hall Effect Seen in Graphene Analog
Graphene’s valence and conduction bands meet at a point, making the single-layer crystal a semimetal. Researchers have predicted that spin-orbit coupling of carbon’s outer electrons opens a narrow gap between these bands—but only for the crystal’s bulk. Along the edges, spin-dependent states bridge the band gap, allowing the resistance-free flow of electrons: a quantum spin Hall effect. The weakness of carbon’s spin-orbit coupling means that this quantum spin Hall effect is too fragile to observe, however. Now Pantelis Bampoulis of the University of Twente in the Netherlands and his collaborators have seen the quantum spin Hall effect in graphene’s germanium (Ge) analog, germanene [1]. Furthermore, they show that germanene’s structure—a honeycomb like graphene’s, but lightly buckled—allows the quantum spin Hall effect to be turned off and on using an electric field.
Bampoulis and his collaborators grew a germanene monolayer on a buffer layer of Ge atop a substrate of Ge2Pt. Using a scanning tunneling microscope, they discriminated between the edge and the bulk states of germanene and measured how current depended on voltage under an external electric field perpendicular to the layer. At low field strengths, germanene exhibited a robust quantum spin Hall effect due to germanium’s strong spin-orbit coupling. At high field strengths, the edge states no longer bridged the gap and germanene became a normal insulator. But at a critical intermediate value, germanene underwent a topological phase transition as the otherwise separated conduction and valence bands in the bulk came together and the symmetry that sustained the quantum spin Hall effect was destroyed.
The robustness of germanene’s quantum spin Hall effect and the fact that it can be turned off with an applied electric field suggest that the material could be used to make room-temperature topological field-effect transistors.
New material facilitates search for room-temperature superconductivity
Scientists from Jilin University, the Center for High Pressure Science and Technology Advanced Research, and Skoltech have synthesized lanthanum-cerium polyhydride, a material that promises to facilitate studies of near-room-temperature superconductivity. It offers a compromise between the polyhydrides of lanthanum and cerium in terms of how much cooling and pressure it requires. This enables easier experiments, which might one day lead scientists to compounds that conduct electricity with zero resistance at ambient conditions—an engineering dream many years in the making. The study was published in Nature Communications.
One of the most intriguing unsolved questions in modern physics is: Can we make a material that conducts electricity with zero resistance (superconducts) at room temperature and atmospheric pressure? Such a superconductor would enable power grids with unprecedented efficiency, ultrafast microchips, and electromagnets so powerful they could levitate trains or control fusion reactors.
In their search, scientists are probing multiple classes of materials, slowly nudging up the temperature they superconduct at and decreasing the pressure they require to remain stable. One such group of materials is polyhydrides—compounds with extremely high hydrogen content. At −23°C, the current champion for high-temperature superconductivity is a lanthanum polyhydride with the formula LaH10. The trade-off: It requires the pressure of 1.5 million atmospheres. At the opposite end of the spectrum, cuprates are a class of materials that superconduct under normal atmospheric pressure but require cooler temperatures —no more than −140°.
Astronomers just saw a star eat a planet—an astrophysicist on the team explains the first-of-its-kind discovery
For the first time, astronomers have captured images that show a star consuming one of its planets. The star, named ZTF SLRN-2020, is located in the Milky Way galaxy, in the constellation Aquila. As the star swallowed its planet, the star brightened to 100 times its normal level, allowing the 26-person team of astronomers I worked with to detect this event as it happened.
I am a theoretical astrophysicist, and I developed the computer models that our team uses to interpret the data we collect from telescopes. Although we only see the effects on the star, not the planet directly, our team is confident that the event we witnessed was a star swallowing its planet. Witnessing such an event for the first time has confirmed the long-standing assumption that stars swallow their planets and has illuminated how this fascinating process plays out.
The team I work with searches for the bursts of light and gas that occur when two stars merge into a bigger, single star. To do this, we have been using data from the Zwicky Transient Facility, a telescope located on Palomar Mountain in Southern California. It takes nightly images of broad swaths of the sky, and astronomers can then compare these images to find stars that change in brightness over time, or what are called astronomical transients.
Team develops the world’s smallest and fastest nano-excitonic transistor
How can Marvel movie character Ant-Man produce such strong energy out of his small body? The secret lies in the transistors on his suit that amplify weak signals for processing. Transistors that amplify electrical signals in the conventional way lose heat energy and limit the speed of signal transfer, which degrades performance. What if it were possible to overcome such limitations and make a high-performance suit that is light and small but without the loss of heat energy?
A POSTECH team of Professor Kyoung-Duck Park and Yeonjeong Koo from the Department of Physics and a team from ITMO University in Russia led by Professor Vasily Kravtsov jointly developed a nano-excitonic transistor using intralayer and interlayer excitons in heterostructure-based semiconductors, which addresses the limitations of existing transistors. The research was recently published in the journal ACS Nano.
Excitons are responsible for light emission of semiconductor materials and are key to developing a next-generation light-emitting element with less heat generation and a light source for quantum information technology due to the free conversion between light and material in their electrically neutral states.
The 5 most significant breakthroughs in quantum computing
Ragsxl/Wikimedia Commons.
Unlike classical computers, which operate on binary bits (0 and 1), quantum computers operate on quantum bits or qubits. Qubits can exist in a state of superposition. This means that any qubit has some probability of existing simultaneously in the 0 and 1 states, exponentially increasing the computational power of quantum computers.