Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: computing – Page 261

Scaling has long been recognized as a major hurdle for quantum processors, along with a need for advances in quantum error correction and the control of quantum gates.

However, while rapid progress has been made in the latter two, far less progress has been made in the development of a CMOS-based scalable system, where the devices and qubits are sufficiently identical that the number of external control signals increases slowly with the number of qubits.

Therefore the development, and taping-out, of a CMOS-based scaling architecture has taken on new significance, as scaling has become the most critical remaining task for building a commercially viable quantum computer.

Read more | >

Organic light-emitting diodes (OLEDs) are now widely used. For use in displays, blue OLEDs are additionally required to supplement the primary colors red and green. Especially in blue OLEDs, impurities give rise to strong electrical losses, which could be partly circumvented by using highly complex and expensive device layouts. A team from the Max Planck Institute for Polymer Research has now developed a new material concept that potentially allows efficient blue OLEDs with a strongly simplified structure.

From televisions to smartphones: (OLEDs) are nowadays finding their way into many devices that we use every day. To display an image, they are needed in the three primary colors red, green and blue. In particular, for are still difficult to manufacture because blue light—physically spoken—has a , which makes the development of materials difficult.

Especially the presence of minute quantities of impurities in the material that cannot be removed plays a decisive role in the performance of these materials. These impurities— , for example—form obstacles for electrons to move inside the diode and participate in the light-generation process. When an electron is captured by such an obstacle, its energy is not converted into light but into heat. This problem, known as “charge trapping”, occurs primarily in blue OLEDs and significantly reduces their efficiency.

Read more | >

When you turn on a lamp to brighten a room, you are experiencing light energy transmitted as photons, which are small, discrete quantum packets of energy. These photons must obey the sometimes strange laws of quantum mechanics, which, for instance, dictate that photons are indivisible, but at the same time, allow a photon to be in two places at once.

Similar to the photons that make up beams of light, indivisible quantum particles called phonons make up a beam of sound. These particles emerge from the collective motion of quadrillions of atoms, much as a “stadium wave” in a sports arena is due to the motion of thousands of individual fans. When you listen to a song, you’re hearing a stream of these very small quantum particles.

Read more | >

Researchers have created a quantum superposition state in a semiconductor nanostructure that might serve as a basis for quantum computing. The trick: two optical laser pulses that act as a single terahertz laser pulse.

A German-Chinese research team has successfully created a quantum bit in a semiconductor nanostructure. Using a special energy transition, the researchers created a state in a quantum dot—a tiny area of the semiconductor—in which an electron hole simultaneously possessed two different energy levels. Such superposition states are fundamental for quantum computing.

However, excitation of the state would require a large-scale free-electron that can emit light in the terahertz range. Additionally, this wavelength is too long to focus the beam on the tiny quantum dot. The German-Chinese team has now achieved the excitation with two finely tuned short-wavelength optical .

Read more | >

For decades, scientists have been probing the potential of two-dimensional materials to transform our world. 2D materials are only a single layer of atoms thick. Within them, subatomic particles like electrons can only move in two dimensions. This simple restriction can trigger unusual electron behavior, imbuing the materials with “exotic” properties like bizarre forms of magnetism, superconductivity and other collective behaviors among electrons—all of which could be useful in computing, communication, energy and other fields.

But researchers have generally assumed that these exotic 2D properties exist only in single-layer sheets, or short stacks. The so-called “bulk” versions of these materials—with their more complex 3D atomic structures—should behave differently.

Or so they thought.

Read more | >

A scalable system for controlling quantum bits demonstrates a very low error rate, which is essential for making practical devices.

A major obstacle to the development of practical quantum computers is the difficulty of scaling up—making a device with large numbers of quantum bits (qubits) that also gives accurate results in the presence of environmental noise. Now researchers report a significant improvement in the accuracy of a technology that is already known to be much easier to scale up than conventional techniques [1]. This alternative technology uses units of magnetic flux called flux quanta to control conventional superconducting qubits. The reduction in the error rate came from physically separating the control circuits from the qubits. With further refinement, the flux-quanta technology could provide a superior pathway to practical quantum computation.

Many current efforts to carry out quantum logic operations—the basic units of computation—use short microwave pulses to control the qubits. Currently, however, this technology is difficult to scale up beyond 1,000 qubits. But the presence of environmental noise requires error-correction methods that rely on large numbers of qubits, perhaps a million or more, for an effective error-correcting system that performs useful computations, according to some estimates.

Read more | >

As fish wriggle, they create a complex push–pull pattern in the water that propels them forward. Many studies have shown how the motion of a fish’s tail forms a vortex around its leading edge that provides thrust; however, it has been difficult to capture how the water flow around other parts of the fish interacts with this vortex to impact the overall propulsion. Jiacheng Guo at the University of Virginia and colleagues recently demonstrated how different fins create currents that can constructively interact to improve swimming efficiency [1].

Guo and colleagues studied how the flow around the lower back—or anal—fin interacts with the flow around the tail—or caudal—fin. First, they took a high-resolution video of a swimming rainbow trout and created a computational fluid dynamics model to accurately reproduce the fish’s motion and the water currents that it induced. Then they modified the anal fin in the model to see how this would change the pattern of water flow around the trout and affect the forward thrust.

The researchers found that the anal fin increases propulsion in two ways. It creates a vortex that stabilizes and strengthens the caudal-fin vortex, and it helps maintain a pressure difference across the fish’s body that reduces drag. Changes to the size or position of the anal fin decreased the swimming efficiency, demonstrating that the natural fish physiology is optimal.

Read more | >

Neuromorphic computers do not calculate using zeros and ones. They instead use physical phenomena to detect patterns in large data streams at blazing fast speed and in an extremely energy-efficient manner.

In their project NIMFEIA, Katrin and Helmut Schultheiß along with their team from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) have now taken this technology a tremendous step forward. They also demonstrated that their approach can be seamlessly integrated into conventional chip manufacturing. Their findings have now been published in Nature Communications.

What the researchers have developed at the HZDR-Institute of Ion Beam Physics and Materials Research is referred to by many names. “Neuromorphic computing,” for example, is one term, as the processes resemble those that occur within the brain. “Unconventional computing” is another name, as the technology is so different from the data processing that we are accustomed to today, which uses the Boolean logic of zeros and ones.

Read more | >