An electrically driven on-chip light source of entangled photon pairs is developed by combining an InP gain section and Si3N4 microrings. A pair generation rate of 8,200 counts s−1 and a coincidence-to-accidental ratio of more than 80 are achieved around the wavelength of 1,550 nm.
There are high expectations that quantum computers may deliver revolutionary new possibilities for simulating chemical processes. This could have a major impact on everything from the development of new pharmaceuticals to new materials. Researchers at Chalmers University have now, for the first time in Sweden, used a quantum computer to undertake calculations within a real-life case in chemistry.
“Quantum computers could in theory be used to handle cases where electrons and atomic nuclei move in more complicated ways. If we can learn to utilize their full potential, we should be able to advance the boundaries of what is possible to calculate and understand,” says Martin Rahm, Associate Professor in Theoretical Chemistry at the Department of Chemistry and Chemical Engineering, who has led the study.
Within the field of quantum chemistry, the laws of quantum mechanics are used to understand which chemical reactions are possible, which structures and materials can be developed, and what characteristics they have. Such studies are normally undertaken with the help of super computers, built with conventional logical circuits. There is however a limit for which calculations conventional computers can handle. Because the laws of quantum mechanics describe the behavior of nature on a subatomic level, many researchers believe that a quantum computer should be better equipped to perform molecular calculations than a conventional computer.
Deep brain stimulation (DBS) is an experimental treatment strategy which uses an implanted device to help patients with severe depression who have reached a point where no other treatment works.
But despite her involvement in the DBS collaboration, which involves neuroscientists, neurosurgeons, electrophysiologists, engineers and computer scientists, neurologist Helen Mayberg does not see it as a long-term solution.
“I hope I live long enough to see that people won’t require a hole in their brain and a device implanted in this way,” she says. “I often have a nightmare with my tombstone that kind of reads like, what did she think she was doing?”
Providing increased resistance to outside interference, topological qubits create a more stable foundation than conventional qubits. This increased stability allows the quantum computer to perform computations that can uncover solutions to some of the world’s toughest problems.
While qubits can be developed in a variety of ways, the topological qubit will be the first of its kind, requiring innovative approaches from design through development. Materials containing the properties needed for this new technology cannot be found in nature—they must be created. Microsoft brought together experts from condensed matter physics, mathematics, and materials science to develop a unique approach producing specialized crystals with the properties needed to make the topological qubit a reality.
Among the biggest environmental problems of our time, micro-and nanoplastic particles (MNPs) can enter the body in various ways, including through food. And now for the first time, research conducted at MedUni Vienna has shown how these minute particles manage to breach the blood-brain barrier and as a consequence penetrate the brain. The newly discovered mechanism provides the basis for further research to protect humans and the environment.
Published in the journal Nanomaterials, the study was carried out in an animal model with oral administration of MNPs, in this case polystyrene, a widely-used plastic which is also found in food packaging. Led by Lukas Kenner (Department of Pathology at MedUni Vienna and Department of Laboratory Animal Pathology at Vetmeduni) and Oldamur Hollóczki (Department of Physical Chemistry, University of Debrecen, Hungary) the research team was able to determine that tiny polystyrene particles could be detected in the brain just two hours after ingestion.
The mechanism that enabled them to breach the blood-brain barrier was previously unknown to medical science. “With the help of computer models, we discovered that a certain surface structure (biomolecular corona) was crucial in enabling plastic particles to pass into the brain,” Oldamur Hollóczki explained.
A giant orbital magnetic moment exists in graphene quantum dots, according to new work by physicists at the University of California Santa Cruz in the US. As well as being of fundamental interest for studying systems with relativistic electrons – that is those travelling at near-light speeds – the work could be important for quantum information science since these moments could encode information.
Graphene, a sheet of carbon just one atom thick, has a number of unique electronic properties, many of which arise from the fact that it is a semiconductor with a zero-energy gap between its valence and conduction bands. Near where the two bands meet, the relationship between the energy and momentum of charge carriers (electrons and holes) in the material is described by the Dirac equation and resembles that of a photon, which is massless.
These bands, called Dirac cones, enable the charge carriers to travel through graphene at extremely high, “ultra-relativistic” speeds approaching that of light. This extremely high mobility means that graphene-based electronic devices such as transistors could be faster than any that exist today.
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In the future, communications networks and computers will use information stored in objects governed by the microscopic laws of quantum mechanics. This capability can potentially underpin communication with greatly enhanced security and computers with unprecedented power. A vital component of these technologies will be memory devices capable of storing quantum information to be retrieved at will.
Virginia Lorenz, a professor of physics at the University of Illinois Urbana-Champaign, studies Lambda-type optical quantum memory devices, a promising technology that relies on light interacting with a large group of atoms. She is developing a device based on hot metallic vapor with graduate student Kai Shinbrough.
As the researchers work towards a practical device, they are also providing some of the first theoretical analyses of Lambda-type devices. Most recently, they reported the first variance-based sensitivity analysis describing the effects of experimental noise and imperfections in Physical Review A.
Year 2021 😗😁
Researchers say algorithms can simulate an infinite quantum system on finite quantum computers in interesting advance for quantum tech.
Accelerating Leadership In Quantum Information Sciences — Dr. Charles Tahan, Ph.D., Assistant Director for Quantum Information Science (QIS); Director, National Quantum Coordination Office, Office of Science and Technology Policy, The White House.
Dr. Charles Tahan, Ph.D. is the Assistant Director for Quantum Information Science (QIS) and the Director of the National Quantum Coordination Office (NQCO) within the White House Office of Science and Technology Policy (https://www.quantum.gov/nqco/). The NQCO ensures coordination of the National Quantum Initiative (NQI) and QIS activities across the federal government, industry, and academia.
Dr. Tahan is on detail from the Laboratory for Physical Sciences (https://www.lps.umd.edu/) where he drove technical progress in the future of information technology as Technical Director. Research at LPS spans computing, communications, and sensing, from novel device physics to high-performance computer architectures. As a technical lead, Dr. Tahan stood up new research initiatives in silicon and superconducting quantum computing; quantum characterization, verification, and validation; and new and emerging qubit science and technology. As a practicing physicist, he is Chief of the intramural QIS research programs at LPS and works with students and postdocs from the University of Maryland-College Park to conduct original research in quantum information and device theory. His contributions have been recognized by the Researcher of the Year Award, the Presidential Early Career Award for Scientists and Engineers, election as a Fellow of the American Physical Society, and as an ODNI Science and Technology Fellow. He continues to serve as Chief Scientist of LPS.
Dr. Tahan earned a PhD in Physics at the University of Wisconsin-Madison in 2005 and a B.Sc. in Physics and Computer Science with Highest Honors from the College of William & Mary in 2000. From 2005–2007 he was a National Science Foundation Distinguished International Postdoctoral Research Fellow at the University of Cambridge, UK; the Center for Quantum Computing Technology, Australia; and the University of Tokyo, Japan. He served as chief technical consultant for quantum information science and technology programs in DARPA’s Microsystems Technology Office (MTO) while at Booz Allen Hamilton from 2007–2009. He has a long-term commitment to science and society including creating one of the first games meant to build intuition about quantum computing.
