Lifeboat Foundation

Now, intriguing calculations from a research team at the Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS), and reported this week in Physics of Plasmas, from AIP Publishing, explain the production and dynamics of electrons and positrons from ultrahigh-intensity laser-matter interactions. In other words: They’ve calculated how to create matter and antimatter via lasers.

Strong electric fields cause electrons to undergo huge radiation losses because a significant amount of their energy is converted into gamma rays — high-energy photons, which are the particles that make up light. The high-energy photons produced by this process interact with the strong laser field and create electron-positron pairs. As a result, a new state of matter emerges: strongly interacting particles, optical fields, and gamma radiation, whose dynamics are governed by the interplay between classical physics phenomena and quantum processes.

A key concept behind the team’s work is based on the quantum electrodynamics (QED) prediction that “a strong electric field can, generally speaking, ‘boil the vacuum,’ which is full of ‘virtual particles,’ such as electron-positron pairs,” explained Igor Kostyukov of IAP RAS. “The field can convert these types of particles from a virtual state, in which the particles aren’t directly observable, to a real one.”

When the quantum computer was imagined 30 years ago, it was revered for its potential to quickly and accurately complete practical tasks often considered impossible for mere humans and for conventional computers. But, there was one big catch: Tiny-scale quantum effects fall apart too easily to be practical for reliably powering computers.

Now, a team of scientists in Japan may have overcome this obstacle. Using laser light, they have developed a precise, continuous control technology giving 60 times more success than previous efforts in sustaining the lifetime of “qubits,” the unit that quantum computers encode. In particular, the researchers have shown that they can continue to create a quantum behavior known as the entangled state—entangling more than one million different physical systems, a world record that was only limited in their investigation by data storage space.

This feat is important because entangled quantum particles, such as atoms, electrons and photons, are a resource of quantum information processing created by the behaviors that emerge at the tiny quantum scale. Harnessing them ushers in a new era of information technology. From such behaviors as superposition and entanglement, quantum particles can perform enormous calculations simultaneously. The report of their investigation appears this week in the journal APL Photonics.

Yesterday, in the New York Review of Books, Freeman Dyson analyzed a trio of recent books on humanity’s future in the larger cosmos. They were How to Make a Spaceship: A Band of Renegades, an Epic Space Race, and the Birth of Private Spaceflight; Beyond Earth: Our Path to a New Home in the Planets; and All These Worlds Are Yours: The Scientific Search for Alien Life.

Dyson is “a brilliant physicist and contrarian,” as the theoretical astrophysicist Lawrence Krauss recently told Nautilus. So I was waiting, as I read his review, to come across his profound and provocative pronouncement about these books, and it came soon enough: “None of them looks at space as a transforming force in the destiny of our species,” he writes. The books are limited in scope by looking at the future of space as a problem of engineering. Dyson has a grander vision. Future humans can seed remote environments with genetic instructions for countless new species. “The purpose is no longer to explore space with unmanned or manned missions, but to expand the domain of life from one small planet to the universe.”

Dyson can be just as final in his opinions on the destiny of scientific investigation. According to Krauss, Dyson once told him, “There’s no way we’re ever going to measure gravitons”—the supposed quantum particles underlying gravitational forces—“because there’s no terrestrial experiment that could ever measure a single graviton.” Dyson told Krauss that, in order to measure one, “you’d have to make the experiment so massive that it would actually collapse to form a black hole before you could make the measurement.” So, Dyson concluded, “There’s no way that we’ll know whether gravity is a quantum theory.”

Continue reading “Lawrence Krauss Versus Freeman Dyson on Gravitons” »

‘Stationary light’ could lead to quantum logic gates – building blocks for quantum computers. Cathal O’Connell reports.

Scientists at the University of Calgary successfully teleported a particle nearly four miles away in a breakthrough experiment that could revolutionize the way computers function.

Researchers used the entanglement property of quantum mechanics, known as “spooky action at a distance,” to teleport a particle. It’s a scientific property not even the renowned Albert Einstein could come to terms with it.

“Being entangled means that the two photons that form an entangled pair have properties that are linked regardless of how far the two are separated,” Dr. Wolfgang Tittel, a physics professor at the University of Calgary who was involved in the research, said in a press statement. “When one of the photons was sent over to City Hall, it remained entangled with the photon that stayed at the University of Calgary. What happened is the instantaneous and disembodied transfer of the photon’s quantum state onto the remaining photon of the entangled pair, which is the one that remained six kilometres [slightly less than 4 miles] away at the university.”

Continue reading “Wonders of Creation: Scientists Use Quantum Mechanics to Teleport Particle 4 Miles” »

Researchers from the Graphene Flagship use layered materials to create an all-electrical quantum light emitting diodes (LED) with single-photon emission. These LEDs have potential as on-chip photon sources in quantum information applications.

Atomically thin LEDs emitting one photon at a time have been developed by researchers from the Graphene Flagship. Constructed of layers of atomically thin materials, including transition metal dichalcogenides (TMDs), graphene, and boron nitride, the ultra-thin LEDs showing all-electrical single photon generation could be excellent on-chip quantum light sources for a wide range of photonics applications for quantum communications and networks. The research, reported in Nature Communications, was led by the University of Cambridge, UK.

The ultra-thin devices reported in the paper are constructed of thin layers of different layered materials, stacked together to form a heterostructure. Electrical current is injected into the device, tunnelling from single-layer graphene, through few-layer boron nitride acting as a tunnel barrier, and into the mono- or bi-layer TMD material, such as tungsten diselenide (WSe2), where electrons recombine with holes to emit single photons. At high currents, this recombination occurs across the whole surface of the device, while at low currents, the quantum behaviour is apparent and the recombination is concentrated in highly localised quantum emitters.

Quantum Goddess

Can the University of New South Wales researcher propel Australia first over the finish line in the race to build a reliable quantum computer? Elizabeth Finkel reports.

Why do we remember the past, but not the future? It seems like a silly question, but for some scientists, it’s a deep mystery wrapped up in physics and perception.

The mystery takes another twist in a study appearing in the same journal that published Albert Einstein’s theories of relativity more than a century ago.

Researchers from the University of Calgary demonstrated that photons’ states could be teleported at a record 6 kilometer distance over “dark fiber.” The team hopes this research could help them establish the fundamentals for a “global quantum internet.”