Circa 2016
Entanglement is an extremely strong correlation that can exist between quantum systems. These correlations are so strong that two or more entangled particles have to be described with reference to each other, even though the individual objects may be spatially separated.
Continue reading “Quantum Entanglement harvesting in a vacuum” »
Like memory in conventional computers, quantum memory components are essential for quantum computers—a new generation of data processors that exploit quantum mechanics and can overcome the limitations of classical computers. With their potent computational power, quantum computers may push the boundaries of fundamental science to create new drugs, explain cosmological mysteries, or enhance accuracy of forecasts and optimization plans. Quantum computers are expected to be much faster and more powerful than their traditional counterparts as information is calculated in qubits, which, unlike the bits used in classical computers, can represent both zero and one in a simultaneous superstate.
Photonic quantum memory allows for the storage and retrieval of flying single-photon quantum states. However, production of such highly efficient quantum memory remains a major challenge as it requires a perfectly matched photon-matter quantum interface. Meanwhile, the energy of a single photon is too weak and can be easily lost into the noisy sea of stray light background. For a long time, these problems suppressed quantum memory efficiencies to below 50 percent—a threshold value crucial for practical applications.
Now, for the first time, a joint research team led by Prof. Du Shengwang from HKUST, Prof. Zhang Shanchao from SCNU, Prof. Yan Hui from SCNU and Prof. Zhu Shi-Liang from SCNU and Nanjing University has found a way to boost the efficiency of photonic quantum memory to over 85 percent with a fidelity of over 99 percent.
Continue reading “Physicists set a new record of quantum memory efficiency” »
For the first time, physicists at the University of Basel have succeeded in measuring the magnetic properties of atomically thin van der Waals materials on the nanoscale. They used diamond quantum sensors to determine the strength of the magnetization of individual atomic layers of the material chromium triiodide. In addition, they found a long-sought explanation for the unusual magnetic properties of the material. The journal Science has published the findings.
The use of atomically thin, two-dimensional van der Waals materials promises innovations in numerous fields in science and technology. Scientists around the world are constantly exploring new ways to stack different single atomic layers and thus engineer new materials with unique, emerging properties.
These super-thin composite materials are held together by van der Waals forces and often behave differently to bulk crystals of the same material. Atomically thin van der Waals materials include insulators, semiconductors, superconductors and a few materials with magnetic properties. Their use in spintronics or ultra-compact magnetic memory media is highly promising.
Scientists find surprising way to affect information storage properties in metal alloy.
Sometimes scientific discoveries can be found along well-trodden paths. That proved the case for a cobalt-iron alloy material commonly found in hard disk drives.
As reported in a recent issue of Physical Review Letters, researchers from the U.S. Department of Energy’s (DOE) Argonne National Laboratory, along with Oakland University in Michigan and Fudan University in China, have found a surprising quantum effect in this alloy.
Continue reading “Researchers discover surprising quantum effect in hard disk drive material” »
Particles travelling through empty space can emit bright flashes of gamma rays by interacting with the quantum vacuum, according to a new study by researchers at the University of Strathclyde.
It has long been known that charged particles, such as electrons and protons, produce the electromagnetic equivalent of a sonic boom when their speeds exceed that of photons in the surrounding medium. This effect, known as Cherenkov emission, is responsible for the characteristic blue glow from water in a nuclear reactor, and is used to detect particles at the CERN Large Hadron Collider.
According to Einstein, nothing can travel faster than light in vacuum. Because of this, it is usually assumed that the Cherenkov emission cannot occur in vacuum. But according to quantum theory, the vacuum itself is packed full of “virtual particles”, which move momentarily in and out of existence.
Continue reading “Extracting something from nothing: A bright glow from empty space” »
Checking out a stack of books from the library is as simple as searching the library’s catalog and using unique call numbers to pull each book from their shelf locations. Using a similar principle, scientists at the Center for Functional Nanomaterials (CFN)—a U.S. Department of Energy (DOE) Office of Science User Facility at Brookhaven National Laboratory—are teaming with Harvard University and the Massachusetts Institute of Technology (MIT) to create a first-of-its-kind automated system to catalog atomically thin two-dimensional (2-D) materials and stack them into layered structures. Called the Quantum Material Press, or QPress, this system will accelerate the discovery of next-generation materials for the emerging field of quantum information science (QIS).
Structures obtained by stacking single atomic layers (“flakes”) peeled from different parent bulk crystals are of interest because of the exotic electronic, magnetic, and optical properties that emerge at such small (quantum) size scales. However, flake exfoliation is currently a manual process that yields a variety of flake sizes, shapes, orientations, and number of layers. Scientists use optical microscopes at high magnification to manually hunt through thousands of flakes to find the desired ones, and this search can sometimes take days or even a week, and is prone to human error.
Once high-quality 2-D flakes from different crystals have been located and their properties characterized, they can be assembled in the desired order to create the layered structures. Stacking is very time-intensive, often taking longer than a month to assemble a single layered structure. To determine whether the generated structures are optimal for QIS applications—ranging from computing and encryption to sensing and communications—scientists then need to characterize the structures’ properties.
Continue reading “Building a printing press for new quantum materials” »
Graphene quantum dots drawn from common coal may be the basis for an effective antioxidant for people who suffer traumatic brain injuries, strokes or heart attacks.
Their ability to quench oxidative stress after such injuries is the subject of a study by scientists at Rice University, the Texas A&M Health Science Center and the McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth).
Quantum dots are semiconducting materials small enough to exhibit quantum mechanical properties that only appear at the nanoscale.
Continue reading “Scientists discover coal-derived ‘dots’ are effective antioxidant” »
University of Copenhagen researchers have developed a nanocomponent that emits light particles carrying quantum information. Less than one-tenth the width of a human hair, the miniscule component makes it possible to scale up and could ultimately reach the capabilities required for a quantum computer or quantum internet. The research result puts Denmark at the head of the pack in the quantum race.
Teams around the world are working to develop quantum technologies. The focus of researchers based at the Center for Hybrid Quantum Networks (Hy-Q) at the University of Copenhagen’s Niels Bohr Institute is on developing quantum communication technology based on light circuits, known as nanophotonic circuits. The UCPH researchers have now achieved a major advancement.
“It is a truly major result, despite the component being so tiny,” says Assistant Professor Leonardo Midolo, who has been working towards this breakthrough for the past five years.
Continue reading “Nanocomponent is a quantum leap for Danish physicists” »
