Posted in particle physics, quantum physics
Nearly 75 years after the puzzling first detection of the kaon, scientists are still looking to the particle for hints of physics beyond their current understanding.
Extremely massive fundamental particles could exist, but they would seriously mess with our understanding of quantum mechanics.
Scientists put diamonds under strain to improve their mechanical properties. The results suggest they may help quantum computers run at room temperature.
Scientists at Freie Universität Berlin develop a deep learning method to solve a fundamental problem in quantum chemistry.
A team of scientists at Freie Universität Berlin has developed an artificial intelligence (AI) method for calculating the ground state of the Schrödinger equation in quantum chemistry. The goal of quantum chemistry is to predict chemical and physical properties of molecules based solely on the arrangement of their atoms in space, avoiding the need for resource-intensive and time-consuming laboratory experiments. In principle, this can be achieved by solving the Schrödinger equation, but in practice this is extremely difficult.
Up to now, it has been impossible to find an exact solution for arbitrary molecules that can be efficiently computed. But the team at Freie Universität has developed a deep learning method that can achieve an unprecedented combination of accuracy and computational efficiency. AI has transformed many technological and scientific areas, from computer vision to materials science. “We believe that our approach may significantly impact the future of quantum chemistry,” says Professor Frank Noé, who led the team effort. The results were published in the reputed journal Nature Chemistry.
Researchers recently resolved a long-standing question in quantum physics, about how long it takes a single atom to tunnel through a barrier.
Scientists are edging closer to making a super-secure, super-fast quantum internet possible: they’ve now been able to ‘teleport’ high-fidelity quantum information over a total distance of 44 kilometres (27 miles).
Both data fidelity and transfer distance are crucial when it comes to building a real, working quantum internet, and making progress in either of these areas is cause for celebration for those building our next-generation communications network.
In this case the team achieved a greater than 90 percent fidelity (data accuracy) level with its quantum information, as well as sending it across extensive fibre optic networks similar to those that form the backbone of our existing internet.
While many institutions are developing quantum computers, making a quantum internet requires a way to transfer the information between computers. This is accomplished by a phenomenon called quantum teleportation, in which two atoms separated by large distances are made to act as if they are identical.
Don Lincoln writes about recent research that has brought us closer to actualizing the goal of a quantum internet, giving us both hope and fear about what it could mean for the future.
Diamond is the hardest material in nature. But out of many expectations, it also has great potential as an excellent electronic material. A joint research team led by City University of Hong Kong (CityU) has demonstrated for the first time the large, uniform tensile elastic straining of microfabricated diamond arrays through the nanomechanical approach. Their findings have shown the potential of strained diamonds as prime candidates for advanced functional devices in microelectronics, photonics, and quantum information technologies.
The research was co-led by Dr. Lu Yang, Associate Professor in the Department of Mechanical Engineering (MNE) at CityU and researchers from Massachusetts Institute of Technology (MIT) and Harbin Institute of Technology (HIT). Their findings have been recently published in the prestigious scientific journal Science, titled “Achieving large uniform tensile elasticity in microfabricated diamond”.
“This is the first time showing the extremely large, uniform elasticity of diamond by tensile experiments. Our findings demonstrate the possibility of developing electronic devices through ‘deep elastic strain engineering’ of microfabricated diamond structures,” said Dr. Lu.
Posted in particle physics, quantum physics
O,.o circa 2018.
The ongoing search for the graviton—the proposed fundamental particle carrying gravitational force—is a crucial step in physicists’ long journey toward a theory of everything.
Quantum computer: One of the obstacles for progress in the quest for a working quantum computer has been that the working devices that go into a quantum computer and perform the actual calculations, the qubits, have hitherto been made by universities and in small numbers. But in recent years, a pan-European collaboration, in partnership with French microelectronics leader CEA-Leti, has been exploring everyday transistors—that are present in billions in all our mobile phones—for their use as qubits. The French company Leti makes giant wafers full of devices, and, after measuring, researchers at the Niels Bohr Institute, University of Copenhagen, have found these industrially produced devices to be suitable as a qubit platform capable of moving to the second dimension, a significant step for a working quantum computer. The result is now published in Nature Communications.
Quantum dots in two dimensional array is a leap ahead
One of the key features of the devices is the two-dimensional array of quantum dots. Or more precisely, a two by two lattice of quantum dots. “What we have shown is that we can realize single electron control in every single one of these quantum dots. This is very important for the development of a qubit, because one of the possible ways of making qubits is to use the spin of a single electron. So reaching this goal of controlling the single electrons and doing it in a 2-D array of quantum dots was very important for us”, says Fabio Ansaloni, former Ph.D. student, now postdoc at center for Quantum Devices, NBI.
A multitasking nanomachine that can act as a heat engine and a refrigerator at the same time has been created by RIKEN engineers. The device is one of the first to test how quantum effects, which govern the behavior of particles on the smallest scale, might one day be exploited to enhance the performance of nanotechnologies.
Conventional heat engines and refrigerators work by connecting two pools of fluid. Compressing one pool causes its fluid to heat up, while rapidly expanding the other pool cools its fluid. If these operations are done in a periodic cycle, the pools will exchange energy and the system can be used as either a heat engine or a fridge.
It would be impossible to set up a macroscale machine that does both tasks simultaneously—nor would engineers want to, says Keiji Ono of the RIKEN Advanced Device Laboratory. “Combining a traditional heat engine with a refrigerator would make it a completely useless machine,” he says. “It wouldn’t know what to do.”
