Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: quantum physics – Page 307

A new experiment uses superconducting qubits to demonstrate that quantum mechanics violates what’s called local realism by allowing two objects to behave as a single quantum system no matter how large the separation between them. The experiment wasn’t the first to show that local realism isn’t how the Universe works—it’s not even the first to do so with qubits.

But it’s the first to separate the qubits by enough distance to ensure that light isn’t fast enough to travel between them while measurements are made. And it did so by cooling a 30-meter-long aluminum wire to just a few milliKelvin. Because the qubits are so easy to control, the experiment provides a new precision to these sorts of measurements. And the hardware setup may be essential for future quantum computing efforts.

Read more | >

The silicon microchips of future quantum computers will be packed with millions, if not billions of qubits—the basic units of quantum information—to solve the greatest problems facing humanity. And with millions of qubits needing millions of wires in the microchip circuitry, it was always going to get cramped in there.

But now engineers at UNSW Sydney have made an important step toward solving a long-standing problem about giving their more breathing space—and it all revolves around jellybeans.

Not the kind we rely on for a sugar hit to get us past the 3pm slump. But jellybean quantum dots—elongated areas between qubit pairs that create more space for wiring without interrupting the way the paired qubits interact with each other.

Read more | >

In the United States, the first step on the road to exascale HPC systems began with a series of workshops in 2007. It wasn’t until a decade and a half later that the 1,686 petaflops “Frontier” system at Oak Ridge National Laboratory went online. This year, Argonne National Laboratory is preparing for the switch to be turned on for “Aurora,” which will be either the second or the third such exascale machine in the United States, depending on the timing of the “El Capitan” system at Lawrence Livermore National Laboratory.

There were delays and setbacks on the road to exascale for all of these machines, as well as technology changes, ongoing competition with China, and other challenges. But don’t expect the next leap to zettascale – or even quantum computing – to be any quicker, according to Rick Stevens, associate laboratory director of computing for environment and life sciences at Argonne. Both could take another 15 to 20 years or more.

Such is the nature of HPC.

Read more | >

Year 2020 face_with_colon_three

A trio of theoretical physicists at the Pennsylvania State University has calculated the upper limit for the possible quantization of time—they suggest 10−33 seconds as the upper limit for the period of a universal oscillator. In their paper published in the journal Physical Review Letters, Garrett Wendel, Luis Martínez and Martin Bojowald outline their theory and suggest a possible way to prove it.

For many years, have been trying to explain a major problem—the suggests that time is a continuous quantity, one that can move slower or faster depending on acceleration and gravity conditions. But quantum mechanics theories suggest that time ticks away at a steady pace, like the frames of a movie being played out. In this scenario, time must be universal. For both theories to be right, this contradiction must be explained in a rational way.

Some theorists have suggested that one possible explanation for the apparent discrepancy is that time can be quantized as spacetime, similar to theories describing quantum gravity. In such a scenario, spacetime is not described as continuous, but is instead divided into smaller units, which would by necessity have to correspond to the Planck length. This is, of course, far too small to be detectable. The would also require that such discrete packets of time would each expire. This scenario suggests there would need to be a universal clock that ticks away at a very small unit of time. And under this scenario, universal time would exist throughout the universe and also interact with matter. It also raises the question of how fast would such a clock tick.

Continue reading “Theorists calculate upper limit for possible quantization of time” | >

A surprise observation of negative mass in exciton–polaritons has added yet another dimension of weirdness to these strange light-matter hybrid particles.

Dr. Matthias Wurdack, Dr. Tinghe Yun and Dr. Eliezer Estrecho from the Department of Quantum Sciences and Technology (QST) were experimenting with exciton polaritons when they realized that under certain conditions the dispersion became inverted—equating to a negative .

To add to the surprise, the unexpected cause has turned out to be losses.

Read more | >

The exotic particles are called non-Abelian anyons, or nonabelions for short, and their Borromean rings exist only as information inside the quantum computer. But their linking properties could help to make quantum computers less error-prone, or more ‘fault-tolerant’ — a key step to making them outperform even the best conventional computers. The results, revealed in a preprint on 9 May1, were obtained on a machine at Quantinuum, a quantum-computing company in Broomfield, Colorado, that formed as the result of a merger between the quantum computing unit of Honeywell and a start-up firm based in Cambridge, UK.

“This is the credible path to fault-tolerant quantum computing,” says Tony Uttley, Quantinuum’s president and chief operating officer.

Other researchers are less optimistic about the virtual nonabelions’ potential to revolutionize quantum computing, but creating them is seen as an achievement in itself. “There is enormous mathematical beauty in this type of physical system, and it’s incredible to see them realized for the first time, after a long time,” says Steven Simon, a theoretical physicist at the University of Oxford, UK.

Read more | >

Scientists at a UK-based tech company believe they are now a step closer to building a quantum computer that can solve real-world problems, after making progress towards creating a system that protects against errors.

Experts at Quantinuum said they have made a “breakthrough” towards making quantum computing fault tolerant, which would give the system the ability to continue operating without interruption, even if one or more of its components fail.

The race to build a fully functional quantum computer has mostly focused on correcting errors that affect the system, but Ilyas Khan, the company’s founder and chief product officer, said no-one has shown “an actual demonstration of a step towards qubits, the quantum equivalent of what we refer to as a ‘bit’ in existing computers, that are naturally fault tolerant”.

Read more | >