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Integrated quantum photonics (IQP) is a promising platform for realizing scalable and practical quantum information processing. Up to now, most of the demonstrations with IQP focus on improving the stability, quality, and complexity of experiments for traditional platforms based on bulk and fiber optical elements. A more demanding question is: “Are there experiments possible with IQP that are impossible with traditional technology?”

This question is answered affirmatively by a team led jointly by Xiao-Song Ma and Labao Zhang from Nanjing University, and Xinlun Cai from Sun Yat-sen University, China. As reported in Advanced Photonics, the team realizes quantum communication using a chip based on silicon photonics with a superconducting nanowire single-photon detector (SNSPD). The excellent performance of this chip allows them to realize optimal time-bin Bell state measurement and to significantly enhance the key rate in quantum communication.

The single photon detector is a key element for quantum key distribution (QKD) and highly desirable for photonic chip integration to realize practical and scalable quantum networks. By harnessing the unique high-speed feature of the optical waveguide-integrated SNSPD, the dead time of single-photon detection is reduced by more than an order of magnitude compared to the traditional normal-incidence SNSPD. This in turn allows the team to resolve one of the long-standing challenges in quantum optics: Optimal Bell-state measurement of time-bin encoded qubits.

VR can soon become perceptually indistinguishable from the physical reality, even superior in many practical ways, and any artificially created “imaginary” world with a logically consistent ruleset of physics would be ultrarealistic. Advanced immersive technologies incorporating quantum computing, AI, cybernetics, optogenetics and nanotech would make this a new “livable” reality within the next few decades. Can this new immersive tech help us decipher the nature of our own “b… See more.

Quantum physicists at the University of Copenhagen are reporting an international achievement for Denmark in the field of quantum technology. By simultaneously operating multiple spin qubits on the same quantum chip, they surmounted a key obstacle on the road to the supercomputer of the future. The result bodes well for the use of semiconductor materials as a platform for solid-state quantum computers.

One of the engineering headaches in the global marathon towards a large functional quantum computer is the control of many basic memory devices – qubits – simultaneously. This is because the control of one qubit is typically negatively affected by simultaneous control pulses applied to another qubit. Now, a pair of young quantum physicists at the University of Copenhagen’s Niels Bohr Institute –PhD student, now Postdoc, Federico Fedele, 29 and Asst. Prof. Anasua Chatterjee, 32,– working in the group of Assoc. Prof. Ferdinand Kuemmeth, have managed to overcome this obstacle.

The brain of the quantum computer that scientists are attempting to build will consist of many arrays of qubits, similar to the bits on smartphone microchips. They will make up the machine’s memory.

The discovery demonstrates a practical method to overcome current challenges in the manufacture of indium gallium nitride (InGaN) LEDs with considerably higher indium concentration, through the formation of quantum dots that emit long-wavelength light. The researchers have uncovered a new way t.

A type of group-III element nitride-based light-emitting diode (LED), indium gallium nitride (InGaN) LEDs were first fabricated over two decades ago in the 90s, and have since evolved to become ever smaller while growing increasingly powerful, efficient, and durable. Today, InGaN LEDs can be found across a myriad of industrial and consumer use cases, including signals & optical communication and data storage – and are critical in high-demand consumer applications such as solid state lighting, television sets, laptops, mobile devices, augmented (AR) and virtual reality (VR) solutions.

Ever-growing demand for such electronic devices has driven over two decades of research into achieving higher optical output, reliability, longevity and versatility from semiconductors – leading to the need for LEDs that can emit different colors of light. Traditionally, InGaN material has been used in modern LEDs to generate purple and blue light, with aluminum gallium indium phosphide (AlGaInP) – a different type of semiconductor – used to generate red, orange, and yellow light. This is due to InGaN’s poor performance in the red and amber spectrum caused by a reduction in efficiency as a result of higher levels of indium required.

Continue reading “New Way To Generate Light Through Pre-Existing Defects in Semiconductor Materials” »

Quantum entanglement—or what Albert Einstein once referred to as “spooky action at a distance”— occurs when two quantum particles are connected to each other, even when millions of miles apart. Any observation of one particle affects the other as if they were communicating with each other. When this entanglement involves photons, interesting possibilities emerge, including entangling the photons’ frequencies, the bandwidth of which can be controlled.

‘Optical Accelerators’ ditch electricity, favoring light as an exchange medium.

Researchers with IBM and Moscow’s Skolkovo Institute have developed “optical accelerators” — optical switches that use light instead of electricity to convey state changes and transmit information. The inventors claim an up to 1,000x speedup compared to traditional transistor-based switches — and there are applications for both classical and quantum computing.

Quantum physicists at the University of Copenhagen are reporting an international achievement for Denmark in the field of quantum technology. By simultaneously operating multiple spin qubits on the same quantum chip, they surmounted a key obstacle on the road to the supercomputer of the future. The result bodes well for the use of semiconductor materials as a platform for solid-state quantum computers.

One of the engineering headaches in the global marathon towards a large functional quantum computer is the control of many basic memory devices—qubits—simultaneously. This is because the control of one qubit is typically negatively affected by simultaneous control pulses applied to another qubit. Now, a pair of young quantum physicists at the University of Copenhagen’s Niels Bohr Institute working in the group of Assoc. Prof. Ferdinand Kuemmeth, have managed to overcome this obstacle.

Global qubit research is based on various technologies. While Google and IBM have come far with quantum processors based on superconductor technology, the UCPH research group is betting on semiconductor qubits—known as spin qubits.

Physicists and engineers have long been interested in creating new forms of matter, those not typically found in nature. Such materials might find use someday in, for example, novel computer chips. Beyond applications, they also reveal elusive insights about the fundamental workings of the universe. Recent work at MIT both created and characterized new quantum systems demonstrating dynamical symmetry—particular kinds of behavior that repeat periodically, like a shape folded and reflected through time.

“There are two problems we needed to solve,” says Changhao Li, a graduate student in the lab of Paola Cappellaro, a professor of nuclear science and engineering. Li published the work recently in Physical Review Letters, together with Cappellaro and fellow graduate student Guoqing Wang. “The first problem was that we needed to engineer such a system. And second, how do we characterize it? How do we observe this symmetry?”

Concretely, the quantum system consisted of a diamond crystal about a millimeter across. The crystal contains many imperfections caused by a nitrogen atom next to a gap in the lattice—a so-called nitrogen-vacancy center. Just like an electron, each center has a quantum property called a spin, with two discrete energy levels. Because the system is a quantum system, the spins can be found not only in one of the levels, but also in a combination of both energy levels, like Schrodinger’s theoretical cat, which can be both alive and dead at the same time.

And they say it’s the world’s fastest.

It appears a quantum computer rivalry is growing between the U.S. and China.

Continue reading “China’s New Quantum Computer Has 1 Million Times the Power of Google’s” »