Science
Researchers Demonstrate Chip-to-Chip Quantum Teleportation | Physics – Sci-News.com
A research team led by University of Bristol scientists has successfully demonstrated quantum teleportation of information between two programmable micrometer-scale silicon chips. The team’s work, published in the journal Nature Physics, lays the groundwork for large-scale integrated photonic quantum technologies for communications and computations.
Llewellyn et al realize an array of microring resonators (MRRs) to generate multiple high-quality single photons, which are monolithically integrated with linear-optic circuits that process multiple qubits with high fidelity and low noise. Image credit: Llewellyn et al, doi: 10.1038/s41567-019-0727-x.
Quantum teleportation offers quantum state transfer of a quantum particle from one place to another by utilizing entanglement.
Teleportation is not only useful for quantum communication but is a fundamental building-block of optical quantum computing.
Establishing an entangled communication link between two chips in the lab however has proven to be highly challenging.
“We were able to demonstrate a high-quality entanglement link across two chips in the lab, where photons on either chip share a single quantum state,” said study first author Dr. Dan Llewellyn, a researcher in the Quantum Engineering Technology Labs at the University of Bristol.
“Each chip was then fully programmed to perform a range of demonstrations which utilize the entanglement.”
“The flagship demonstration was a two-chip teleportation experiment, whereby the individual quantum state of a particle is transmitted across the two chips after a quantum measurement is performed.”
“This measurement utilizes the strange behavior of quantum physics, which simultaneously collapses the entanglement link and transfers the particle state to another particle already on the receiver chip.”
“Based on our previous result of on-chip high quality single-photon sources, we have built an even more complex circuit containing four sources,” added study co-author Dr. Imad Faruque, also from the Quantum Engineering Technology Labs at the University of Bristol.
“All of these sources are tested and found to be nearly identical emitting nearly identical photons, which is an essential criterion for the set of experiments we had performed, such as entanglement swapping.”
The results showed extremely high-fidelity quantum teleportation of 91%.
In addition, the team was able to demonstrate some other important functionality of their designs, such as entanglement swapping (required for quantum repeaters and quantum networks) and four-photon GHZ states (required in quantum computing and the quantum internet).
“Low loss, high stability, and excellent controllability are extremely important for integrated quantum photonics,” said study co-author Dr. Yunhong Ding, a researcher in the Department of Photonics Engineering and the Center for Silicon Photonics for Optical Communication at Technical University of Denmark.
“In the future, a single silicon-chip integration of quantum photonic devices and classical electronic controls will open the door for fully chip-based CMOS-compatible quantum communication and information processing networks,” said Dr. Jianwei Wang, a scientist at Peking University and corresponding author of the study.
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D. Llewellyn et al. Chip-to-chip quantum teleportation and multi-photon entanglement in silicon. Nat. Phys, published online December 23, 2019; doi: 10.1038/s41567-019-0727-x
Science
Misconceptions about science fuel pandemic debates and controversies, says Neil deGrasse Tyson – CBC.ca
Astrophysicist Neil deGrasse Tyson says some of the bitter arguments about medicine and science during the COVID-19 pandemic can be blamed on a fundamental misunderstanding of science.
“People were unwittingly witnessing science at its very best.… [They said,] ‘You told me not to wear a mask a month ago and now you tell me [to] wear it.… You don’t know what you’re talking about.’ Yes, we do,” the American astrophysicist and author told The Sunday Magazine host Piya Chattopadhyay.
“Science is a means of querying nature. And when we have enough experiments and enough observations, only then can we say: This is how nature behaves, whether you like it or not. And that is when science contributes to what is to what is objectively true in the world.”
Tyson, who is also the director at the Hayden Planetarium in New York City, is doing his part to try to make his corner of the scientific world more accessible with his new book A Brief Welcome to the Universe, co-authored with Michael A. Strauss and J. Richard Gott.
He hopes readers can take those lessons to other scientific topics, including the COVID-19 pandemic, which has seen several controversies flourish about the nature of the virus and the measures developed to fight it.
Misconceptions about how science works stems in part, he said, from the fact that it’s often improperly taught at the earliest levels of education.
“People think science is the answer. ‘Oh, give me the answer. You’re a scientist. What’s the answer?’ And then I say things like: ‘We actually don’t have an answer to that.’ And people get upset. They even get angry. ‘You’re a scientist. You should know,'” he explained.
“What’s not taught in school is that science is a way of learning what is and is not true. The scientific method is a way of ensuring that your own bias does not leave you thinking something is true that is not, or that something is not true that is.”
Big universe, simple language
A Brief Welcome to the Universe is billed as an approachable “pocket-sized tour” of the cosmos, answering such questions as “How do stars live and die?” and “How did the universe begin?”
It’s a condensed version of the 2016 edition of the book, Welcome to the Universe: An Astrophysical Tour.
Tyson and his co-authors argue in the book that astrophysics uses simpler language than other scientific disciplines, which makes it a good starting point to learn about science.
“I don’t simplify the origin of the universe and then call it ‘The Big Bang’ to you. We call it that to each other,” said Tyson. The same goes for well-known phenomena like black holes, sunspots and the planet Jupiter’s Great Red Spot, he added.
Start with those, and then you can move onto other topics, some with more complex names — such as the Coriolis force, which, among other things, explains how the Earth’s rotation subtly affects the way a football travels in the air during a field kick.
“There are simple things in science. And if you’re interested, you can then go out and learn the complex things. But I’m not going to lead with the complex things. What good is that? That never solved anything,” he said.
Many people likely know Tyson from his appearances on American talk shows, often critiquing or debunking questionable science seen in movies and other pop culture. He’s commented on everything from the feasibility of resurrecting dinosaurs, like in Jurassic Park, to the improper night-sky backdrop in the final scenes of Titanic.
He also talks about science on his podcast StarTalk, as well as on a National Geographic TV show of the same name and another show called Cosmos.
Tyson was temporarily removed from both programs in late 2018, after accusations of sexual misconduct from two women, which he denied. Following an investigation, in early 2019, National Geographic and Fox reinstated Tyson on their shows. They did not address the allegations in their statement announcing the decision.
About Pluto
Perhaps none of the topics Tyson is known for speaking about has sparked more discussion than Pluto, the former ninth planet.
“Oh, don’t get me started,” Tyson responded immediately upon mention of the icy celestial body, which was demoted from planet to dwarf planet status in 2006 by the International Astronomical Union.
The term “dwarf planet” is relatively new. It grouped Pluto, which was originally discovered in 1930, with a number of other icy bodies larger than an asteroid but smaller in size and mass to rocky planets closer to the Sun, including the Earth.
“The word planet really should be discarded,” he said. “Because if I say I discovered a planet orbiting a star, you have to ask me 20 more questions to get any understanding of what the hell the thing is.”
The word “planet” comes from the Greek planetes, meaning “wanderer.” In ancient times, that included Mercury, Venus, Mars, Jupiter and Saturn, but also the moon and the sun. Earth wasn’t considered a planet, because it was believed to be the unmoving centre of the known universe.
Over time, the scientific method progressed beyond that: the Earth is a planet that orbits the sun, which is a star. We now know our moon is one of at least 200 moons in the solar system.
To Tyson, Pluto’s reclassification represents the next step in our evolving understanding of the cosmos, which has necessarily become more complex.
It also illustrates a broadening of our scientific horizons that ancient civilizations might have never contemplated.
That’s why when Tyson was asked how to best answer a child’s question about things we do not know, such as “how big is the universe,” he said the best thing we can say is that we do not know.
“That is one of the greatest answers you can ever give someone — because it leaves them wanting for more. And they might one day be the person who discovers what the answer will be.”
Written by Jonathan Ore. Produced by Sarah-Joyce Battersby.
Science
2.8-pound meteorite from space crashes roof of Canadian woman’s home, falls on bed – The Tribune India
Tribune Web Desk
Chandigarh, October 16
Ruth Hamilton (66) had a disturbed awakening on October 3 when a large meteorite plunged from space, through her roof and landed in her bed.
Ruth, resident of Golden, British Columbia, woke up to the sound of a crash and her dog barking on October 3 around 11.35 pm.
Speaking with Canadian Press, she said: “I’ve never been so scared in my life, adding that, “I wasn’t sure what to do so I called 911 and, when I was speaking with the operator, I flipped over my pillow and saw that a rock had slipped between two pillows.”
She told CTV News: “I didn’t feel it.”
“It never touched me. I had debris on my face from the drywall, but not a single scratch.”
A police officer arrived on the scene, but suspected the object that landed in Hamilton’s bed was from a nearby construction site.
“He called the [construction site] and they said they hadn’t done a blast but that they had seen an explosion in the sky and, right then and there, we realised it was a meteorite,” she told the Canadian Press.
It turns out that the 2.8-pound space rock, about the size of a small cabbage, was part of a meteor shower identified by Alan Hildebrand, a planetary scientist in the Department of Geoscience at the University of Calgary, and his colleagues.
The group said the trajectory of the meteorite that hit Hamilton’s house would have made it visible throughout southeastern British Columbia and central and southern Alberta.
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NASA is set on Saturday to launch a first-of-its kind mission, dubbed Lucy, to study Jupiter’s Trojan asteroids, two large clusters of space rocks that scientists believe are remnants of primordial material that formed the solar system’s outer planets.
The space probe, packed inside a special cargo capsule, is due for liftoff from Cape Canaveral Air Force Station in Florida at 5:34 a.m. EDT (0934 GMT), carried aloft by an Atlas V rocket from United Launch Alliance (UAL), a joint venture of Boeing Co and Lockheed Martin Corp.
If all goes according to plan, Lucy will be hurled into space on a 12-year expedition to study a record number of asteroids. It will be the first to explore the Trojans, thousands of rocky objects orbiting the sun in two swarms – one ahead of the path of giant gas planet Jupiter and one behind it.
The largest known Trojan asteroids, named for the warriors of Greek mythology, are believed to measure as much as 225 kilometers (140 miles) in diameter.
Scientists hope Lucy’s close-up fly-by of seven Trojans will yield new clues to how the solar system’s planets came to be formed some 4.5 billion years ago and what shaped their present configuration.
Believed to be rich in carbon compounds, the asteroids may even provide new insights into the origin of organic materials and life on Earth, NASA said.
“The Trojan asteroids are leftovers from the early days of our solar system, effectively the fossils of planet formation,” principal mission investigator Harold Levison of the Southwest Research Institute in Boulder, Colorado, was quoted by NASA as saying.
No other single science mission has been designed to visit as many different objects independently orbiting the sun in the history of space exploration, NASA said.
As well as the Trojans, Lucy will do a fly-by of an asteroid in the solar system’s main asteroid belt, called DonaldJohanson in honor of the lead discoverer of the fossilized human ancestor known as Lucy, from which the NASA mission takes its name. The Lucy fossil, unearthed in Ethiopia in 1974, was in turn named for the Beatles hit “Lucy in the Sky with Diamonds.”
Lucy the asteroid probe will make spaceflight history in another way. Following a route that circles back to Earth three times for gravitational assists, it will be the first spacecraft ever to return to Earth’s vicinity from the outer solar system, according to NASA.
The probe will use rocket thrusters to maneuver in space and two rounded solar arrays, each the width of a school bus, to recharge batteries that will power the instruments contained in the much smaller central body of the spacecraft.
(Reporting by Steve Gorman in Los Angeles, Editing by Rosalba O’Brien)
Misconceptions about science fuel pandemic debates and controversies, says Neil deGrasse Tyson – CBC.ca
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