Lifeboat Foundation

“Open Article” smile Spin-based quantum computers have the potential to tackle difficult mathematical problems that cannot be solved using ordinary computers, but many problems remain in making these machines scalable. Now, an international group of researchers led by the RIKEN Center for Emergent Matter Science have crafted a new architecture for quantum computing. By constructing a hybrid device made from two different types of qubit—the fundamental computing element of quantum computers –they have created a device that can be quickly initialized and read out, and that simultaneously maintains high control fidelity.

Single-spin qubits in semiconductor quantum dots hold promise for universal quantum computation with demonstrations of a high single-qubit gate fidelity above 99.9% and two-qubit gates in conjunction with a long coherence time. However, initialization and readout of a qubit is orders of magnitude slower than control, which is detrimental for implementing measurement-based protocols such as error-correcting codes. In contrast, a singlet-triplet qubit, encoded in a two-spin subspace, has the virtue of fast readout with high fidelity. Here, we present a hybrid system which benefits from the different advantages of these two distinct spin-qubit implementations. A quantum interface between the two codes is realized by electrically tunable inter-qubit exchange coupling. We demonstrate a controlled-phase gate that acts within 5.5 ns, much faster than the measured dephasing time of 211 ns. The presented hybrid architecture will be useful to settle remaining key problems with building scalable spin-based quantum computers.

Qubits or quantum bits are the fundamental building block for quantum information processes. Whereas conventional computers store and process data as a series of ‘1’s and ‘0’s, quantum computers use the properties of a quantum system, such as the polarization of a photon or the spin of an electron.

Read the latest Research articles in Qubits from Nature Communications.

Hacker attacks on everything from social media accounts to government files could be largely prevented by the advent of quantum communication, which would use particles of light called “photons” to secure information rather than a crackable code.

Using light to send information is a game of probability: Transmitting one bit of information can take multiple attempts. The more photons a light source can generate per second, the faster the rate of successful information transmission.

“A source might generate a lot of photons per second, but only a few of them may actually be used to transmit information, which strongly limits the speed of quantum communication,” Bogdanov said.

Continue reading “Toward unhackable communication: Single particles of light could bring the ‘quantum internet’” »

Researchers at the US Department of Energy’s (DOE’s) Oak Ridge National Laboratory (ORNL) has developed and tested a new #Interferometer

January 3, 2019 — By analyzing a pattern formed by the intersection of two beams of light, researchers can capture elusive details regarding the behavior of mysterious phenomena such as gravitational waves. Creating and precisely measuring these interference patterns would not be possible without instruments called interferometers.

For over three decades, scientists have attempted to improve the sensitivity of interferometers to better detect how the number of photons—particles that make up visible light and other forms of electromagnetic energy—leads to changes in light phases. Attempts to achieve this goal are often hampered by optical loss and noise, both of which can decrease the accuracy of interferometer measurements.

Continue reading “Novel fiber-optic device lays foundation for quantum-enhanced measurements” »

ARMONK, N.Y., Jan. 4, 2019 /PRNewswire/ — IBM (NYSE: IBM) Chairman, President and CEO Ginni Rometty will deliver the opening keynote at CES 2019 on Tuesday, Jan. 8. CES is the largest and one of the most influential technology events in the world.

Rometty will show how technologies like artificial intelligence, blockchain and cloud are reshaping the world of business, and, in turn, our daily lives. She also will talk about what’s coming next in these pioneering technologies – and how new data will revolutionize how we live, work and play. Rometty shares perspective on the future of technology in the Consumer Technology Association magazine It Is Innovation (i3) CES edition: https://www.nxtbook.com/nxtbooks/manifest/i3_20190102

Rometty will be joined onstage by Ed Bastian, CEO of Delta Air Lines; Charles Redfield, executive vice president of Food for Walmart; and Vijay Swarup, vice president of R&D for ExxonMobil.

Continue reading “IBM CEO Ginni Rometty Delivers Opening Keynote at CES 2019 on What’s Next in Artificial Intelligence, Blockchain and Quantum Computing” »

A new initiative could push us into the quantum computing era.

After developing a method to control exciton flows at room temperature, EPFL scientists have discovered new properties of these quasiparticles that can lead to more energy-efficient electronic devices.

They were the first to control exciton flows at room temperature. And now, the team of scientists from EPFL’s Laboratory of Nanoscale Electronics and Structures (LANES) has taken their technology one step further. They have found a way to control some of the properties of excitons and change the polarization of the light they generate. This can lead to a new generation of electronic devices with transistors that undergo less energy loss and heat dissipation. The scientists’ discovery forms part of a new field of research called valleytronics and has just been published in Nature Photonics.

Excitons are created when an electron absorbs light and moves into a higher energy level, or “energy band” as they are called in solid quantum physics. This excited electron leaves behind an “electron hole” in its previous energy band. And because the electron has a negative charge and the hole a positive charge, the two are bound together by an electrostatic force called a Coulomb force. It’s this electron-electron hole pair that is referred to as an exciton.

Continue reading “Excitons pave the way to higher-performance electronics” »

Within days of each other back in 1998, two teams published the results of the first real-world quantum computations. But the first quantum computers weren’t computers at all. They were biochemistry equipment, relying on the same science as MRI machines.

You might think of quantum computing as a hyped-up race between computer companies to build a powerful processing device that will make more lifelike AI, revolutionize medicine, and crack the encryption that protects our data. And indeed, the prototype quantum computers of the late 1990s indirectly led to the quantum computers built by Google and IBM. But that’s not how it all began—it started with physicists tinkering with mathematics and biochemistry equipment for curiosity’s sake.

Rice University physicists have created the world’s first laser-cooled neutral plasma, completing a 20-year quest that sets the stage for simulators that re-create exotic states of matter found inside Jupiter and white dwarf stars.

The findings are detailed this week in the journal Science and involve new techniques for laser cooling clouds of rapidly expanding plasma to temperatures about 50 times colder than deep space.

Continue reading “Next up: Ultracold simulators of super-dense stars” »