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Quantum Computing Breakthrough: Silicon Qubits Interact at Long-Distance – SciTechDaily

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Researchers at Princeton University have made an important step forward in the quest to build a quantum computer using silicon components, which are prized for their low cost and versatility compared to the hardware in today’s quantum computers. The team showed that a silicon-spin quantum bit (shown in the box) can communicate with another quantum bit located a significant distance away on a computer chip. The feat could enable connections between multiple quantum bits to perform complex calculations. Credit: Felix Borjans, Princeton University

Princeton scientists demonstrate that two silicon quantum bits can communicate across relatively long distances in a turning point for the technology.

Imagine a world where people could only talk to their next-door neighbor, and messages must be passed house to house to reach far destinations.

Until now, this has been the situation for the bits of hardware that make up a silicon quantum computer, a type of quantum computer with the potential to be cheaper and more versatile than today’s versions.

Now a team based at Princeton University has overcome this limitation and demonstrated that two quantum-computing components, known as silicon “spin” qubits, can interact even when spaced relatively far apart on a computer chip. The study was published today (December 25, 2019) in the journal Nature.

“The ability to transmit messages across this distance on a silicon chip unlocks new capabilities for our quantum hardware,” said Jason Petta, the Eugene Higgins Professor of Physics at Princeton and leader of the study. “The eventual goal is to have multiple quantum bits arranged in a two-dimensional grid that can perform even more complex calculations. The study should help in the long term to improve communication of qubits on a chip as well as from one chip to another.”

Quantum computers have the potential to tackle challenges beyond the capabilities of everyday computers, such as factoring large numbers. A quantum bit, or qubit, can process far more information than an everyday computer bit because, whereas each classical computer bit can have a value of 0 or 1, a quantum bit can represent a range of values between 0 and 1 simultaneously.

To realize quantum computing’s promise, these futuristic computers will require tens of thousands of qubits that can communicate with each other. Today’s prototype quantum computers from Google, IBM and other companies contain tens of qubits made from a technology involving superconducting circuits, but many technologists view silicon-based qubits as more promising in the long run.

Silicon spin qubits have several advantages over superconducting qubits. The silicon spin qubits retain their quantum state longer than competing qubit technologies. The widespread use of silicon for everyday computers means that silicon-based qubits could be manufactured at low cost.

The challenge stems in part from the fact that silicon spin qubits are made from single electrons and are extremely small.

“The wiring or ‘interconnects’ between multiple qubits is the biggest challenge towards a large scale quantum computer,” said James Clarke, director of quantum hardware at Intel, whose team is building silicon qubits using using Intel’s advanced manufacturing line, and who was not involved in the study. “Jason Petta’s team has done great work toward proving that spin qubits can be coupled at long distances.”

To accomplish this, the Princeton team connected the qubits via a “wire” that carries light in a manner analogous to the fiber optic wires that deliver internet signals to homes. In this case, however, the wire is actually a narrow cavity containing a single particle of light, or photon, that picks up the message from one qubit and transmits it to the next qubit.

The two qubits were located about half a centimeter, or about the length of a grain of rice, apart. To put that in perspective, if each qubit were the size of a house, the qubit would be able to send a message to another qubit located 750 miles away.

The key step forward was finding a way to get the qubits and the photon to speak the same language by tuning all three to vibrate at the same frequency. The team succeeded in tuning both qubits independently of each other while still coupling them to the photon. Previously the device’s architecture permitted coupling of only one qubit to the photon at a time.

“You have to balance the qubit energies on both sides of the chip with the photon energy to make all three elements talk to each other,” said Felix Borjans, a graduate student and first author on the study. “This was the really challenging part of the work.”

Each qubit is composed of a single electron trapped in a tiny chamber called a double quantum dot. Electrons possess a property known as spin, which can point up or down in a manner analogous to a compass needle that points north or south. By zapping the electron with a microwave field, the researchers can flip the spin up or down to assign the qubit a quantum state of 1 or 0.

“This is the first demonstration of entangling electron spins in silicon separated by distances much larger than the devices housing those spins,” said Thaddeus Ladd, senior scientist at HRL Laboratories and a collaborator on the project. “Not too long ago, there was doubt as to whether this was possible, due to the conflicting requirements of coupling spins to microwaves and avoiding the effects of noisy charges moving in silicon-based devices. This is an important proof-of-possibility for silicon qubits because it adds substantial flexibility in how to wire those qubits and how to lay them out geometrically in future silicon-based ‘quantum microchips.’”

The communication between two distant silicon-based qubits devices builds on previous work by the Petta research team. In a 2010 paper in the journal Science, the team showed it is possible to trap single electrons in quantum wells. In the journal Nature in 2012, the team reported the transfer of quantum information from electron spins in nanowires to microwave-frequency photons, and in 2016 in Science they demonstrated the ability to transmit information from a silicon-based charge qubit to a photon. They demonstrated nearest-neighbor trading of information in qubits in 2017 in Science. And the team showed in 2018 in Nature that a silicon spin qubit could exchange information with a photon.

Jelena Vuckovic, professor of electrical engineering and the Jensen Huang Professor in Global Leadership at Stanford University, who was not involved in the study, commented: “Demonstration of long-range interactions between qubits is crucial for further development of quantum technologies such as modular quantum computers and quantum networks. This exciting result from Jason Petta’s team is an important milestone towards this goal, as it demonstrates non-local interaction between two electron spins separated by more than 4 millimeters, mediated by a microwave photon. Moreover, to build this quantum circuit, the team employed silicon and germanium – materials heavily used in the semiconductor industry.”

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Reference: “Resonant microwave-mediated interactions between distant electron spins” by F. Borjans, X. G. Croot, X. Mi, M. J. Gullans and J. R. Petta, 25 December 2019, Nature.
DOI: 10.1038/s41586-019-1867-y

In addition to Borjans and Petta, the following contributed to the study: Xanthe Croot, a Dicke postdoctoral fellow; associate research scholar Michael Gullans; and Xiao Mi, who earned his Ph.D. at Princeton in Petta’s group and is now a research scientist at Google.

The study was funded by Army Research Office (grant W911NF-15-1-0149) and the Gordon and Betty Moore Foundation’s EPiQS Initiative (grant GBMF4535).

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Korea realises its ambitions and already travels to meet the moon – Atalayar

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The Republic of Korea has been keen to demonstrate that it is in fact Asia’s fourth-largest space power and ranks just behind China, Japan and India in terms of space ambitions and development. 

With the launch of its first moon-bound probe, it has made it clear that although it is considered to be the world’s tenth largest economy, it is one of the seven nations globally with the greatest interest in outer space. The South Korean scientific spacecraft is called Danuri, which in English means “enjoy the moon”, weighs 678 kilos, is cube-shaped, measures 3.18 x 6.3 x 2.67 metres and, according to the Seoul government, cost 182 million dollars. 

PHOTO/KARI – The Danuri lunar probe carries six scientific instruments, weighs 678 kilos, is cube-shaped, measures 3.18 x 6.3 x 2.67 metres and has required an investment of 182 million dollars

In a way, Korea has followed in the footsteps of the United Arab Emirates, which relied on Japan and its H-IIA rocket to send its first interplanetary probe, the Al Amal Mars spacecraft, to Mars. In the Korean case, it has chosen its great ally, the United States, and Danuri’s liftoff took place late on 4 August from the Cape Canaveral launch complex in Florida. A Falcon 9 vector from US tycoon Elon Musk’s SpaceX company was responsible for launching it en route.

The spacecraft took off on the same day that US Congresswoman Nancy Pelosi arrived in Seoul to support the Asian country in maintaining a strong deterrent against North Korea and seeking its denuclearisation. South Korean President Yoon Suk-yeol, who took office on 10 May, had the opportunity to speak to Pelusi by phone, thanking him for his gesture and explaining that Danuri will serve “to boost Korea’s space economy and scientific expertise”. 

If the probe succeeds in reaching lunar orbit, the Republic of Korea will become the seventh nation to explore the Moon in situ, as Russia, the United States, China, India, the European Space Agency and Japan have already done. But the South Korean mission is not an isolated initiative. “The first step of our national space exploration programme is the moon,” says Science Minister Lee Jong-ho. 

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PHOTO/AP – The launch of the South Korean spacecraft into space from Florida coincided in date (4 August) with a quick visit to Seoul by the Speaker of the US House of Representatives, Nancy Pelosi

Hyundai and Kia to be on the moon in 2031

The president of the Korea Aerospace Research Institute (KARI), Professor Lee Sang-ryool, has confirmed that “there are technologies we need to improve, but we can travel and land on the moon with our own capabilities”. Seoul aims to launch a lunar surface module together with a small rover by 2031.

And they are already working on it. On 27 July, the car manufacturers Hyundai and Kia signed an agreement with six Korean research institutes to develop robotic technologies to equip the country’s future space rover. The project is joined by Korea’s extensive space business network, which manufactures satellites and even the KSLV-II Nuri launcher, which successfully completed its second successful flight into space from the Naro space centre in southern Korea on 21 October

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PHOTO/KARI – The KARI lunar exploration programme envisages the probe now launched, to be followed by a lander with a rover to investigate the soil of our natural satellite by 2030

Regarding the Danuri probe – also known as the Korea Pathfinder Lunar Orbiter or KPLO – the Korean Ministry of Science and Telecommunications has already verified its proper operational status in orbit and confirmed that “the solar panels are generating sufficient power and all on-board devices are working properly”. 

It is being monitored throughout the mission by NASA’s three Deep Space Network communications stations: the US station at Goldstone, California; the Australian station near Canberra; and the Spanish station located in the municipality of Robledo de Chavela, near Madrid. Korea also maintains partial contact with the probe via the large satellite dish it has built in Yeoju, Gyeonggi Province.

Danuri will reach its long-awaited goal by the end of the year and not in about six days, the time it took the Apollo 11 mission in 1969 to travel nearly 400,000 kilometres. The reason is that the South Korean spacecraft does not follow a direct trajectory, which consumes a lot of energy. Instead, it flies in the direction of the Sun. It follows a so-called “lunar ballistic transfer” trajectory with low energy and fuel consumption, until it reaches the so-called Lagrange Point 1 (L1), located 1.56 million kilometres from our Blue Planet, where the Sun’s attraction is balanced by the Earth’s attraction. There it will slow down and be re-routed towards the Moon. 

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PHOTO/KARI – The probe is being tracked by NASA’s three Deep Space Network communications complexes (Goldstone, Canberra and Spain’s Robledo de Chávela) along with Korea’s Yeoju

135 days to reach lunar orbit

It is a similar path to that followed by the small American probe Capstone. Weighing 25 kilos and launched into orbit by NASA on 28 June from New Zealand, it is scheduled to reach the moon on 13 November, i.e. it will take 136 days to reach the moon.

If the Danuri mission goes according to the calculations of the KARI engineers, the probe will be captured by the Moon on 16 December after 135 days, i.e. four and a half months after the start of its flight. On 31 December, it will be placed in a circular orbit at an altitude of a hundred kilometres above the lunar surface. Once it has stabilised and the six scientific instruments on board have been checked, the spacecraft will begin observing and collecting data in early January. 

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PHOTO/KARI –  Danuri does not follow a direct trajectory. It flies on a low-energy, low-fuel-consumption lunar ballistic transfer flight on its way to LaGrange Point 1 (L1), where it will be re-routed to the Moon

One of the instruments has been provided by NASA. It is the ShadowCam camera, an evolution of the one on board the US Lunar Reconnaissance Orbiter probe, launched on 18 June 2009, but about 200 times more sensitive. Its task is to map with a resolution of up to 1.7 metres per pixel the ground of the lunar regions at both poles that are always in shadow. The ShadowCam is intended to locate water ice deposits and other resources to help plan future manned missions and build sustainable bases.

ShadowCam and communications are not NASA’s only contribution. The Agency is providing technical assistance, navigation technologies and, in collaboration with the Korea Electronics and Telecommunications Research Institute, a kind of interplanetary Internet to prevent disruption of transmissions to Earth. 

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PHOTO/KARI – The president of the Korea Aerospace Research Institute (KARI), Professor Lee Sang-ryool, says Korea needs to improve its space technologies, but can travel to and land on the moon with its own capabilities

The other four instruments are a magnetometer (KMAG) to track the magnetic field between the Earth and the Moon; a gamma-ray spectrometer (KGRS) to search for spontaneous gamma-ray bursts produced by massive dying stars; a wide-angle polarimetric camera (PolCam) to analyse the properties of grains deposited on the lunar surface. For the descent mission planned for 2031, it incorporates a high-resolution camera (LUTI), which will provide images for KARI technicians to determine the most suitable landing sites.

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Scientist's photo of 'distant star' was actually a slice of chorizo – USA TODAY

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A French scientist apologized after tweeting a photo of a slice of chorizo that he claimed was a deep-space image of a “distant star” snapped by the James Webb Space Telescope.

Étienne Klein, a physicist and research director at France’s Alternative Energies and Atomic Energy Commission, shared the spicy Spanish sausage shot on social media last week, applauding the “level of detail” it provided.

“Picture of Proxima Centauri, the nearest star to the Sun, located 4.2 light years away from us. It was taken by the James Webb Space Telescope. This level of detail … A new world is unveiled everyday,” he posted on Twitter Sunday to more than 91,000 followers.

The first images from the $10 billion telescope – launched Dec. 25, 2021 – went viral throughout July when they were released to the public. The scientific marvel, a joint project involving NASA, the Canadian Space Agency and the European Space Agency, has traveled 1 million miles through space.

A few days after his post, Klein revealed the photo he tweeted was not from the world’s most powerful space telescope. He admitted he tweeted a slice of the reddish, speckled meat.

“When it’s time for the aperitif, cognitive biases seem to have a field day … beware, then, of them,” he played off in further tweets. “According to contemporary cosmology, no object belonging to Spanish charcuterie exists anywhere but on Earth.”

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“I feel compelled to clarify that this tweet showing an alleged snapshot of Proxima Centauri was a form of amusement. Let us learn to be wary of arguments from authority as much as of the spontaneous eloquence of certain images,” he wrote, as translated by Google.

Natalie Neysa Alund covers trending news for USA TODAY. Reach her at nalund@usatoday.com and follow her on Twitter @nataliealund.

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Top Scientist Admits Webb Telescope Star Photo Was Actually Chorizo – PetaPixel

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A prominent French physicist is apologizing after admitting that a viral “distant star” photo he shared on Twitter was not actually captured by the $10 billion James Webb Space Telescope (JWST) but was rather just a slice of chorizo pork sausage.

On July 31st, Etienne Klein, research director of the French Alternative Energies and Atomic Energy Commission, tweeted the photo to his 90,000+ followers on Twitter and claimed that it was a new Webb telescope photo showing the closest star to our Sun.

“Picture of Proxima Centauri, the nearest star to the Sun, located 4.2 light years away from us,” Klein wrote in the Tweet (as translated by Google). “It was taken by the James Webb Space Telescope. This level of detail… A new world is unveiled day after day.”

A screenshot of Etienne Klein’s Tweet.

The tweet went viral and was retweeted thousands of times as people marveled at the imaging power of the Webb telescope, which has been wowing the world with never-before-possible space photos, including shots of the oldest galaxies ever observed.

In follow-up tweets, Klein revealed that what he had Tweeted was just a slice of Spanish sausage.

“Well, when it’s cocktail hour, cognitive bias seem to find plenty to enjoy… Beware of it,” Klein writes. “According to contemporary cosmology, no object related to Spanish charcuterie exists anywhere else other than on Earth.

“In view of some comments, I feel compelled to clarify that this tweet showing an alleged snapshot of Proxima Centauri was a form of amusement. Let us learn to be wary of arguments from authority as much as of the spontaneous eloquence of certain images…”

After receiving angry backlash to his tweet, however, the scientist apologized a few days later for spreading “fake news” that confused quite a number of people, stating that it was just a joke that was intended to warn his followers to be cautious about photos seen online.

“I come to present my apologies to those whom my hoax, which had nothing original about it, may have shocked,” he writes. “I simply wanted to urge caution with images that seem eloquent on their own. A scientist’s joke.”

Prominent French physicist Etienne Klein. Photo by Thesupermat and licensed under CC BY-SA 3.0.

Klein also tweeted Webb’s recent gorgeous photo of the Cartwheel Galaxy, assuring his followers that the photo was “real this time.”

“This is the first time I’ve made a joke when I’m more on this network as a figure of scientific authority,” the physicist later told the Paris-based news magazine Le Point. “The good news is that some immediately understood the deception, but it also took two tweets to clarify, ”explains the researcher.

“It also illustrates the fact that on this type of social network, fake news is always more successful than real news. I also think that if I hadn’t said it was a James-Webb photo, it wouldn’t have been so successful.”

The James Webb Space Telescope launched in December 2021 and officially began making scientific observations on July 12th, 2022. Now the largest optical telescope in space, it is using its unprecedented imaging capabilities to capture pioneering astronomical and cosmological images, including shots of atmospheres of exoplanets as well as the first stars and galaxies created at the beginning of the universe.

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