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Single photon converter: key component of quantum internet

A Polish-British team of physicists has constructed and tested a compact, efficient converter capable of modifying the quantum properties of individual photons. The new device should facilitate the construction of complex quantum computers, and in the future may become an important element in global quantum networks, the successors of today’s Internet.

Quantum internet and hybrid quantum computers, built out of subsystems that operate by means of various physical phenomena, are now becoming more than just the stuff of imagination. In an article just published in the journal Nature Photonics, physicists from the University of Warsaw’s Faculty of Physics (FUW) and the University of Oxford have unveiled a key element of such systems: an electro-optical device that enables the properties of individual photons to be modified. Unlike existing laboratory constructions, this new device works with previously unattainable efficiency and is at the same time stable, reliable, and compact.

Building an efficient device for modifying the quantum state of individual photons was an exceptionally challenging task, given the fundamental differences between classical and quantum computing.

Tracking the flow of quantum information

If objects in motion are like rainwater flowing through a gutter and landing in a puddle, then quantum objects in motion are like rainwater that might end up in a bunch of puddles, all at once. Figuring out where quantum objects actually go has frustrated scientists for years.

Now a Yale-led group of researchers has derived a formula for understanding where quantum objects land when they are transmitted. It’s a development that offers insight for controlling open quantum systems in a variety of situations.

“The formula we derive turns out to be very useful in operating a quantum computer,” said Victor Albert, first author of a study published in the journal Physical Review X. “Our result says that, in principle, we can engineer ‘rain gutters’ and ‘gates’ in a system to manipulate quantum objects, either after they land or during their actual flow.”

New Monolayer Material Could Unlock Nano-Scale Electronics

Research out of New York University’s Tandon School of Engineering has found a new method for developing electronics at the atomic scale — and it’s difficult to get much smaller than that.

Scientists and engineers have previously tried developing electronics using two-dimensional or monolayer electronic materials like graphene to make transistors, but found that the material’s lack of an energy band gap poses difficulties for semiconductor applications.

The new research by assistant professor of electrical and computer engineering Davood Shahrjerdi and doctoral student Abdullah Alharbi, has shown that using a monolayer of tungsten disulfide might be the key to unlocking the potential in nano-scale electronics.

Quantum Computing: Large Molecules Can Be Used To Create Stable Qubit Gates, Manchester University Researchers Say

A team of researchers from the University of Manchester announced Monday they had taken a significant step forward in the creation of viable quantum computers. In a study published in the latest edition of the journal Chem, the researchers provided evidence that large molecules made of nickel and chromium could be used as qubits — the quantum computing equivalent of the bits used to store and process information in conventional computers.

According to the study, it is possible, at least in theory, to use molecular chemistry to connect these molecules, thereby creating several stable qubits that can then be used to create two-qubit logic gates.

“We have shown that the chemistry is achievable for bringing together two-qubit gates — the molecules can be made and the gates can be assembled,” lead author Richard Winpenny said in a statement. “The next step is to show that they work.”

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