Light-Based Quantum Computer Exceeds Fastest Classical Supercomputers (scientificamerican.com) 6
An anonymous reader quotes a report from Scientific American: For the first time, a quantum computer made from photons -- particles of light -- has outperformed even the fastest classical supercomputers. Physicists led by Chao-Yang Lu and Jian-Wei Pan of the University of Science and Technology of China (USTC) in Shanghai performed a technique called Gaussian boson sampling with their quantum computer, named Jiuzhang. The result, reported in the journal Science, was 76 detected photons -- far above and beyond the previous record of five detected photons and the capabilities of classical supercomputers.
Unlike a traditional computer built from silicon processors, Jiuzhangis an elaborate tabletop setup of lasers, mirrors, prisms and photon detectors. It is not a universal computer that could one day send e-mails or store files, but it does demonstrate the potential of quantum computing. Last year, Google captured headlines when its quantum computer Sycamore took roughly three minutes to do what would take a supercomputer three days (or 10,000 years, depending on your estimation method). In their paper, the USTC team estimates that it would take the Sunway TaihuLight, the third most powerful supercomputer in the world, a staggering 2.5 billion years to perform the same calculation as Jiuzhang. [...] This latest demonstration of quantum computing's potential from the USTC group is critical because it differs dramatically from Google's approach. Sycamore uses superconducting loops of metal to form qubits; in Jiuzhang, the photons themselves are the qubits. Independent corroboration that quantum computing principles can lead to primacy even on totally different hardware "gives us confidence that in the long term, eventually, useful quantum simulators and a fault-tolerant quantum computer will become feasible," Lu says.
... [T]he USTC setup is dauntingly complicated. Jiuzhang begins with a laser that is split so it strikes 25 crystals made of potassium titanyl phosphate. After each crystal is hit, it reliably spits out two photons in opposite directions. The photons are then sent through 100 inputs, where they race through a track made of 300 prisms and 75 mirrors. Finally, the photons land in 100 slots where they are detected. Averaging over 200 seconds of runs, the USTC group detected about 43 photons per run. But in one run, they observed 76 photons -- more than enough to justify their quantum primacy claim. It is difficult to estimate just how much time would be needed for a supercomputer to solve a distribution with 76 detected photons -- in large part because it is not exactly feasible to spend 2.5 billion years running a supercomputer to directly check it. Instead, the researchers extrapolate from the time it takes to classically calculate for smaller numbers of detected photons. At best, solving for 50 photons, the researchers claim, would take a supercomputer two days, which is far slower than the 200-second run time of Jiuzhang.
Unlike a traditional computer built from silicon processors, Jiuzhangis an elaborate tabletop setup of lasers, mirrors, prisms and photon detectors. It is not a universal computer that could one day send e-mails or store files, but it does demonstrate the potential of quantum computing. Last year, Google captured headlines when its quantum computer Sycamore took roughly three minutes to do what would take a supercomputer three days (or 10,000 years, depending on your estimation method). In their paper, the USTC team estimates that it would take the Sunway TaihuLight, the third most powerful supercomputer in the world, a staggering 2.5 billion years to perform the same calculation as Jiuzhang. [...] This latest demonstration of quantum computing's potential from the USTC group is critical because it differs dramatically from Google's approach. Sycamore uses superconducting loops of metal to form qubits; in Jiuzhang, the photons themselves are the qubits. Independent corroboration that quantum computing principles can lead to primacy even on totally different hardware "gives us confidence that in the long term, eventually, useful quantum simulators and a fault-tolerant quantum computer will become feasible," Lu says.
... [T]he USTC setup is dauntingly complicated. Jiuzhang begins with a laser that is split so it strikes 25 crystals made of potassium titanyl phosphate. After each crystal is hit, it reliably spits out two photons in opposite directions. The photons are then sent through 100 inputs, where they race through a track made of 300 prisms and 75 mirrors. Finally, the photons land in 100 slots where they are detected. Averaging over 200 seconds of runs, the USTC group detected about 43 photons per run. But in one run, they observed 76 photons -- more than enough to justify their quantum primacy claim. It is difficult to estimate just how much time would be needed for a supercomputer to solve a distribution with 76 detected photons -- in large part because it is not exactly feasible to spend 2.5 billion years running a supercomputer to directly check it. Instead, the researchers extrapolate from the time it takes to classically calculate for smaller numbers of detected photons. At best, solving for 50 photons, the researchers claim, would take a supercomputer two days, which is far slower than the 200-second run time of Jiuzhang.
Reversal of Biological Clock Restores Vision In Old Mice (scitechdaily.com) 26
John Trumpian shares a report from SciTechDaily: Harvard Medical School scientists have successfully restored vision in mice by turning back the clock on aged eye cells in the retina to recapture youthful gene function. The team's work, described today in Nature, represents the first demonstration that it may be possible to safely reprogram complex tissues, such as the nerve cells of the eye, to an earlier age. In addition to resetting the cells' aging clock, the researchers successfully reversed vision loss in animals with a condition mimicking human glaucoma, a leading cause of blindness around the world.
The achievement represents the first successful attempt to reverse glaucoma-induced vision loss, rather than merely stem its progression, the team said. If replicated through further studies, the approach could pave the way for therapies to promote tissue repair across various organs and reverse aging and age-related diseases in humans. Sinclair and colleagues caution that the findings remain to be replicated in further studies, including in different animal models, before any human experiments. Nonetheless, they add, the results offer a proof of concept and a pathway to designing treatments for a range of age-related human diseases.
For their work, the team used an adeno-associated virus (AAV) as a vehicle to deliver into the retinas of mice three youth-restoring genes -- Oct4, Sox2 and Klf4 -- that are normally switched on during embryonic development. The three genes, together with a fourth one, which was not used in this work, are collectively known as Yamanaka factors. The treatment had multiple beneficial effects on the eye. First, it promoted nerve regeneration following optic-nerve injury in mice with damaged optic nerves. Second, it reversed vision loss in animals with a condition mimicking human glaucoma. And third, it reversed vision loss in aging animals without glaucoma.
The achievement represents the first successful attempt to reverse glaucoma-induced vision loss, rather than merely stem its progression, the team said. If replicated through further studies, the approach could pave the way for therapies to promote tissue repair across various organs and reverse aging and age-related diseases in humans. Sinclair and colleagues caution that the findings remain to be replicated in further studies, including in different animal models, before any human experiments. Nonetheless, they add, the results offer a proof of concept and a pathway to designing treatments for a range of age-related human diseases.
For their work, the team used an adeno-associated virus (AAV) as a vehicle to deliver into the retinas of mice three youth-restoring genes -- Oct4, Sox2 and Klf4 -- that are normally switched on during embryonic development. The three genes, together with a fourth one, which was not used in this work, are collectively known as Yamanaka factors. The treatment had multiple beneficial effects on the eye. First, it promoted nerve regeneration following optic-nerve injury in mice with damaged optic nerves. Second, it reversed vision loss in animals with a condition mimicking human glaucoma. And third, it reversed vision loss in aging animals without glaucoma.
SOURCE: Arecibo Observatory, a U.S. National Science Foundation facility
Drone Footage Shows the Shocking Collapse of the Arecibo Observatory (theverge.com) 91
Iwastheone shares a report from The Verge: Today, the National Science Foundation (NSF) released shocking footage of the collapse of the Arecibo Observatory in Puerto Rico. The video, captured on December 1st, shows the moment when support cables snapped, causing the massive 900-ton structure suspended above Arecibo to fall onto the observatory's iconic 1,000-foot-wide dish.
The videos of the collapse were captured by a camera located in Arecibo's Operations Control Center, as well as from a drone located above the platform at the time of collapse. The operator of the drone was able to adjust the drone camera once the platform started to fall and capture the moment of impact. NSF, which oversees Arecibo, had been doing hourly monitoring of the observatory with drones, ever since engineers warned that the structure was on the verge of collapsing in November. The footage highlights the moment when multiple cables snapped, causing the platform to swing outward and hit the side of the dish. The collapse also brought down the tops of the three support towers surrounding Arecibo, where the cables had been connected to keep the platform in the air. Slashdot reader joshgs shares a petition to rebuild the Arecibo Observatory. "On December 1, the platform of the 305-meter radio telescope at Arecibo Observatory suffered a catastrophic collapse," the petition states. "This telescope had many capabilities that cannot be replaced by any existing or planned facility. It had the world's most powerful and most sensitive planetary radar system, providing unparalleled capacity to track and characterize near-Earth asteroids. The telescope was also a source of tourism, education, and pride for the people of Puerto Rico, inspiring many to pursue careers in science and technology."
"We ask Congress to allocate funding to build a new Arecibo radio telescope with greater capabilities than the previous telescope -- to maintain American leadership in planetary defense, astronomy, and ionospheric studies; and to inspire a new generation of scientists."
The videos of the collapse were captured by a camera located in Arecibo's Operations Control Center, as well as from a drone located above the platform at the time of collapse. The operator of the drone was able to adjust the drone camera once the platform started to fall and capture the moment of impact. NSF, which oversees Arecibo, had been doing hourly monitoring of the observatory with drones, ever since engineers warned that the structure was on the verge of collapsing in November. The footage highlights the moment when multiple cables snapped, causing the platform to swing outward and hit the side of the dish. The collapse also brought down the tops of the three support towers surrounding Arecibo, where the cables had been connected to keep the platform in the air. Slashdot reader joshgs shares a petition to rebuild the Arecibo Observatory. "On December 1, the platform of the 305-meter radio telescope at Arecibo Observatory suffered a catastrophic collapse," the petition states. "This telescope had many capabilities that cannot be replaced by any existing or planned facility. It had the world's most powerful and most sensitive planetary radar system, providing unparalleled capacity to track and characterize near-Earth asteroids. The telescope was also a source of tourism, education, and pride for the people of Puerto Rico, inspiring many to pursue careers in science and technology."
"We ask Congress to allocate funding to build a new Arecibo radio telescope with greater capabilities than the previous telescope -- to maintain American leadership in planetary defense, astronomy, and ionospheric studies; and to inspire a new generation of scientists."
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