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A European team of researchers including physicists from the University of Konstanz has found a way of transporting electrons at times below the femtosecond range by manipulating them with light. This could have major implications for the future of data processing and computing.

Contemporary electronic components, which are traditionally based on silicon semiconductor technology, can be switched on or off within picoseconds (i.e. 10^-12 seconds). Standard mobile phones and computers work at maximum frequencies of several gigahertz (1 GHz = 10⁹ Hz) while individual transistors can approach one terahertz (1 THz = 10¹² Hz). Further increasing the speed at which electronic switching devices can be opened or closed using the standard technology has since proven a challenge. A recent series of experiments – conducted at the University of Konstanz and reported in a recent publication in Nature Physics – demonstrates that electrons can be induced to move at sub-femtosecond speeds, i.e. faster than 10^-15 seconds, by manipulating them with tailored light waves.

“This may well be the distant future of electronics,” says Alfred Leitenstorfer, Professor of Ultrafast Phenomena and Photonics at the University of Konstanz (Germany) and co-author of the study. “Our experiments with single-cycle light pulses have taken us well into the attosecond range of electron transport”. Light oscillates at frequencies at least a thousand times higher than those achieved by purely electronic circuits: One femtosecond corresponds to 10^-15 seconds, which is the millionth part of a billionth of a second. Leitenstorfer and his team from the Department of Physics and the Center for Applied Photonics (CAP) at the University of Konstanz believe that the future of electronics lies in integrated plasmonic and optoelectronic devices that operate in the single-electron regime at optical – rather than microwave – frequencies. “However, this is very basic research we are talking about here and may take decades to implement,” he cautions.

Even ordinary computers flip a bit here and there, but their quantum cousins have a lot more ways to go wrong.

As the power and qubits in quantum computing systems increase, so does the need for cutting-edge capabilities to ascertain that they work. The Army Research Office and National Security Agency recently teamed up to solicit proposals for research that can help do exactly that.

The entities launched a broad agency announcement this week to boost the development of innovative techniques and protocols that allow for Quantum Characterization, Verification, and Validation, or QCVV, of intermediate-scale quantum systems. QCVV is essentially the science of quantifying how well a quantum computer can run quantum algorithms—and experts agree that it’s a necessary step towards useful quantum computing.

Earlier this year, we celebrated a first in the field of quantum physics: scientists were able to ‘teleport’ a qutrit, or a piece of quantum information based on three states, opening up a whole host of new possibilities for quantum computing and communication.

Up until then, quantum teleportation had only been managed with qubits, albeit over impressively long distances. This proof-of-concept study suggests future quantum networks will be able to carry much more data and with less interference than we thought.

If you’re new to the idea of qutrits, first let’s take a step back. Simply put, the small data units we know as bits in classical computing can be in one of two states: a 0 or a 1. But in quantum computing, we have the qubit, which can be both a 0 and 1 at the same time (known as superposition).

The ability to process qubits is what allows a quantum computer to perform functions a binary computer simply cannot, like computations involving 500-digit numbers. To do so quickly and on demand might allow for highly efficient traffic flow. It could also render current encryption keys mere speedbumps for a computer able to replicate them in an instant. #QuantumComputing

Multiply 1,048,589 by 1,048,601, and you’ll get 1,099,551,473,989. Does this blow your mind? It should, maybe! That 13-digit prime number is the largest-ever prime number to be factored by a quantum computer, one of a series of quantum computing-related breakthroughs (or at least claimed breakthroughs) achieved over the last few months of the decade.

An IBM computer factored this very large prime number about two months after Google announced that it had achieved “quantum supremacy”—a clunky term for the claim, disputed by its rivals including IBM as well as others, that Google has a quantum machine that performed some math normal computers simply cannot.

Continue reading “The ‘Quantum Computing’ Decade Is Coming—Here’s Why You Should Care” »

Imagine a world where people could only talk to their next-door neighbor, and messages must be passed house to house to reach far destinations.

Until now, this has been the situation for the bits of hardware that make up a silicon quantum computer, a type of quantum computer with the potential to be cheaper and more versatile than today’s versions.

Now a team based at Princeton University has overcome this limitation and demonstrated that two quantum-computing components, known as silicon “spin” qubits, can interact even when spaced relatively far apart on a computer chip. The study was published in the journal Nature.

Scientists have created thin films made from barium zirconium sulfide (BaZrS₃) and confirmed that the materials have alluring electronic and optical properties predicted by theorists.

The films combine exceptionally strong light absorption with good charge transport—two qualities that make them ideal for applications such as photovoltaics and light-emitting diodes (LEDs).

In solar panels, for example, experimental results suggest that BaZrS₃ films would be much more efficient at converting sunlight into electricity than traditional silicon-based materials with identical thicknesses, says lead researcher Hao Zeng, Ph.D., professor of physics in the University at Buffalo College of Arts and Sciences. This could lower solar energy costs, especially because the new films performed admirably even when they had imperfections. (Manufacturing nearly flawless materials is typically more expensive, Zeng explains.)

A European team of researchers including physicists from the University of Konstanz has found a way of transporting electrons at times below the femtosecond range by manipulating them with light. This could have major implications for the future of data processing and computing.

Contemporary electronic components, which are traditionally based on silicon semiconductor technology, can be switched on or off within picoseconds (i.e. 10^-12 seconds). Standard mobile phones and computers work at maximum frequencies of several gigahertz (1 GHz = 10⁹ Hz) while individual transistors can approach one terahertz (1 THz = 10¹² Hz). Further increasing the speed at which electronic switching devices can be opened or closed using the standard technology has since proven a challenge. A recent series of experiments—conducted at the University of Konstanz and reported in a recent publication in Nature Physics—demonstrates that electrons can be induced to move at sub-femtosecond speeds, i.e. faster than 10^-15 seconds, by manipulating them with tailored light waves.

“This may well be the distant future of electronics,” says Alfred Leitenstorfer, Professor of Ultrafast Phenomena and Photonics at the University of Konstanz (Germany) and co-author of the study. “Our experiments with single-cycle light pulses have taken us well into the attosecond range of electron transport.” Light oscillates at frequencies at least a thousand times higher than those achieved by purely electronic circuits: One femtosecond corresponds to 10^-15 seconds, which is the millionth part of a billionth of a second. Leitenstorfer and his team from the Department of Physics and the Center for Applied Photonics (CAP) at the University of Konstanz believe that the future of electronics lies in integrated plasmonic and optoelectronic devices that operate in the single-electron regime at optical—rather than microwave—frequencies. “However, this is very basic research we are talking about here and may take decades to implement,” he cautions.

#28 in our top science stories of 2019.

Nearly one in six deaths from prostate cancer could be prevented if targeted screening was introduced for men at a higher genetic risk of the disease, according to a new UCL-led computer modelling study.

Prostate cancer is the most common form of cancer in men with around 130 new cases diagnosed in the UK every day and more than 10,000 men a year dying as a result of the disease. However, unlike breast and cervical cancer there is currently no national screening programme for this disease in the UK.

A blood test that detects raised levels of the prostate-specific antigen (PSA) can be used to screen for prostate cancer. However, this test is not a reliable indicator as it does not accurately distinguish between dangerous cancers from harmless ones—leading to both unnecessary operations and missed cancers that are harmful.