A team of researchers working at the University of Vienna, has developed a technique for verifying results produced by a quantum computer. In their paper published in the journal Nature Physics, the researchers explain how their method uses one simple quantum computer to verify results produced by another that is far more powerful.
One of the perplexing puzzles that computer scientists have been struggling with is in figuring out how to prove that results obtained using advanced computers are correct. If a computer is used, for example, to perform a calculation and returns a result that can be had no other way, how can the answer be verified? That question has come up more and more often as scientists move closer to developing true quantum computers—machines that in all likelihood will be able to provide answers to all manner of mysterious questions. But how will we know that the answers they give us, are right?
One idea is to create two different types of computers that arrive at answers using completely different architectures, then set them both to work on the same problem to see if they agree. Such a scenario would be the ideal—unfortunately, at this point, it doesn’t appear likely that a new type of architecture capable of keeping up with a quantum computer is likely to come along any time soon, thus, scientists have to look for other options. In this effort by the team in Vienna, the researchers are looking to use a second quantum computer to verify results given by a first, despite being far less powerful.
The team used a method known as blind quantum computing to test a single quantum computation by testing the correctness of measurements performed in obtaining the result. Going about it this way means the computer doing the testing, called the verifier, doesn’t have to have the power of the computer being tested, called the server. Quantum blind testing involves using what are known as trap qubits—qubits that are entangled between both of the computers. Verifying (not testing, technically) is done by preparing the trap qubits in a way that is known to the verifier but not the server.
A measurement angle (again unknown to the server) for a trap qubit is chosen which is predetermined by the verifier—allowing it to detect measurement errors (called cheating) by the server. The location of the trap bits are chosen randomly, allowing for calculating the probability of cheating errors by the server at different processing points. The end result is a number that represents the probability that the result given by the more powerful quantum computer is correct. Thus, the method involves testing the way an answer is arrived at, rather than whether the answer is itself actually correct.
Quantum computers are expected to offer substantial speed-ups over their classical counterparts and to solve problems intractable for classical computers. Beyond such practical significance, the concept of quantum computation opens up fundamental questions, among them the issue of whether quantum computations can be certified by entities that are inherently unable to compute the results themselves. Here we present the first experimental verification of quantum computation. We show, in theory and experiment, how a verifier with minimal quantum resources can test a significantly more powerful quantum computer. The new verification protocol introduced here uses the framework of blind quantum computing and is independent of the experimental quantum-computation platform used. In our scheme, the verifier is required only to generate single qubits and transmit them to the quantum computer. We experimentally demonstrate this protocol using four photonic qubits and show how the verifier can test the computer’s ability to perform quantum computation.
A team of researchers working at China’s National Laboratory of Solid State Microstructures and Department of Physics has developed a means for mimicking gravitational lensing in a way that allows for viewing laser light actually being bent around a sphere. In their paper published in the journal Nature Photonics, the team describes how they constructed their microstructure, how it works and ways it might be used for a practical purpose.
Physicists have known for almost a century that when light passes by an object, it is bent by the object’s gravitational pull. The bigger an object, or the stronger its gravitational pull, the more light can be bent. With an object such as a black hole, the pull can be so great as to cause the light to bend all the way around it, creating what is known as a photon sphere. In the real world, such events cannot be witnessed of course, because the light becomes trapped. In this new effort, the researchers sought to create a structure that would mimic light being bent around a sphere, but in a way that would allow it to be seen.
The structure the team built is based on refracted light and the fact that different materials diffract light a different amount. The team started with a microscopic sized ball of polystyrene. They then used a spin coating process to cover the central sphere with a polymer coating—the spin technique allowed for varying the thickness of the polymer creating a material with a constantly changing degree of refraction. The varying degrees of refraction caused a laser light shone through the sphere to bend, effectively mimicking the action of black hole. But, because the light was being refracted into the center of the sphere, the researchers wouldn’t be able to see it—also just like a black hole. To get around this problem the researchers added quantum dots to the polymer coating—they absorbed a small amount of the laser light and then emitted it as red light—at an angle—directing it towards the researchers who recorded it all on videotape.
In the video, the light from the laser can be seen bending as it’s brought close to the sphere, eventually reaching a point where it’s bent all the way around the sphere, creating an artificial photon sphere. The structure mimics a black hole and thus conforms to Einstein’s theory of general relativity, and for that reason, the researchers believe it can be used as a research tool. They suggest it might also prove useful in directing light onto solar cells.
One of the most fascinating predictions of the theory of general relativity is the effect of gravitational lensing, the bending of light in close proximity to massive stellar objects. Recently, artificial optical materials have been proposed to study the various aspects of curved spacetimes, including light trapping and Hawking radiation. However, the development of experimental ‘toy’ models that simulate gravitational lensing in curved spacetimes remains a challenge, especially for visible light. Here, by utilizing a microstructured optical waveguide around a microsphere, we propose to mimic curved spacetimes caused by gravity, with high precision. We experimentally demonstrate both far-field gravitational lensing effects and the critical phenomenon in close proximity to the photon sphere of astrophysical objects under hydrostatic equilibrium. The proposed microstructured waveguide can be used as an omnidirectional absorber, with potential light harvesting and microcavity applications.
This little chip may be hardly the size of a speck of glitter, but don’t underestimate what it can do. It’s actually a particle accelerator that is able to boost electrons at a rate 10 times greater than a conventional accelerator, all in a millimeters-long package.
The chip is a step in developing smaller, faster, cheaper accelerators called dielectric laser accelerators. Theoretically, a 100-foot-long dielectric laser accelerator could be just as powerful as the Stanford Linear Accelerator Center’s 2-mile-long machine, according to the center, where the chip was developed.
There’s still a ways to go before researchers would be able to build a laser accelerator. For one thing, the new SLAC chip still requires a conventional accelerator, which gets its power from microwaves, to get things started. But in the future, if the technology does work, SLAC engineers imagine it could go into security scanners (accelerators at the airport?), university labs, and medical imaging devices hospitals could afford, they wrote in a paper they published today in the journal Nature.
When electrons go through these new chips, they first get kicked off through the SLAC’s accelerator. Then they enter the chip through a channel that’s only half a micron wide. A commercially available infrared laser beamed through the channel, along with the channel’s precise ridges, boosts the energy of the electrons further. The SLAC National Accelerator Laboratory put together a nice explanation:
An easier way for diabetics to control their insulin intake
The U.S. Food and Drug Administration has approved its first “artificial pancreas” to automatically control the insulin levels of diabetics.
The hormone insulin controls blood sugar levels and is normally produced in the body by the pancreas. But in Type 1 diabetics (and sometimes Type 2), the pancreas just doesn’t make insulin, meaning diabetics’ bodies can’t regulate blood sugar levels. This system, designed by Minneapolis-based medical tech company Medtronic, is a wearable little gadget that stops insulin delivery automatically when glucose levels get too low, hopefully keeping the wearer from going into a diabetic coma.
Unlike traditional insulin pumps, which require the wearer to still monitor blood sugar levels and manually program the pump to deliver insulin, this one monitors blood sugar for you, and delivers the appropriate amount accordingly. With a traditional pump, the device can keep delivering insulin even when the your blood sugar is too low, lowering levels even further and sometimes causing loss of consciousness. This is especially dangerous during sleep, when you can’t exactly gauge your own blood sugar. Medtronic’s MiniMed 530G system can detect up to 93 percent of hypoglycemia (low blood sugar) episodes, and will sound an alarm to wake you up if your blood sugar gets too low. If you don’t respond, the system will shut off insulin delivery for two hours, hopefully staving off dangerously low blood sugar levels.
One caveat: Medtronic got a warning letter from the FDA only a few weeks ago related to manufacturing processes of their Paradigm Insulin Infusion Pumps (which are used in this system) at their facility in Northridge, Calif. The pumps had been recalled in June because they were malfunctioning and delivering either too much or not enough insulin, and the FDA found the company was not doing enough to verify that the failure wouldn’t happen again. The company said in the press release accompanying the product approval that it had “already addressed many of the observations noted in the warning letter and is committed to resolving the remaining observations as quickly as possible.”
What is a bully?
The origin of the bullying behavior.
Why do people “choose” to adopt the bullying behavior?
What can you do to help a “bully”
What can you teach a “bully” ?
With a wide variety of nutrients ranging from magnesium and manganese to copper, protein and zinc, pumpkin seeds are nutritional powerhouses wrapped up in a very small package. They also contain plant compounds known as phytosterols and free-radical scavenging antioxidants, which can give your health an added boost.
Best of all, because pumpkin seeds are highly portable and require no refrigeration, they make an excellent snack to keep with you whenever you’re on the go, or they can be used as a quick anytime snack at home, too.
9 Top Health Benefits of Pumpkin Seeds
One-quarter cup of pumpkin seeds contains nearly half of the recommended daily amount of magnesium, which participates in a wide range of vitally important physiological functions, including the creation of ATP (adenosine triphospate, the energy molecules of your body), the synthesis of RNA and DNA, the pumping of your heart, proper bone and tooth formation, relaxation of your blood vessels, and proper bowel function.
Magnesium has been shown to benefit your blood pressure and help prevent sudden cardiac arrest, heart attack, and stroke, yet an estimated 80 percent of Americans are deficient in this important mineral.
2. Zinc for Immune Support
Pumpkin seeds are a rich source of zinc (one ounce contains more than 2 mg of this beneficial mineral). Zinc is important to your body in many ways, including immunity, cell growth and division, sleep, mood, your senses of taste and smell, eye and skin health, insulin regulation, and male sexual function.
Many are deficient in zinc due to mineral-depleted soils, drug effects, plant-based diets, and other diets high in grain. This deficiency is associated with increased colds and flu, chronic fatigue, depression, acne, low birth weight babies, learning problems and poor school performance in children, among others.
3. Plant-Based Omega-3 Fats
Raw nuts and seeds, including pumpkin seeds, are one of the best sources of plant-based omega-3s (alpha-linolenic acid (ALA)). We all need ALA, however, ALA has to be converted by your body into the far more essential omega-3 fats EPA and DHA — by an enzyme in which the vast majority of us have impaired by high insulin levels. So, while pumpkin seeds are an excellent source of ALA, I believe it is essential to get some of your omega-3 fats from animal sources, such as krill oil, as well.
4. Prostate Health
Pumpkin seeds have long been valued as an important natural food for men’s health. This is in part because of their high zinc content, which is important for prostate health (where it is found in the highest concentrations in the body), and also because pumpkin seed extracts and oils may play a role in treating benign prostatic hyperplasia (BPH, or enlarged prostate). Research suggests that both pumpkin seeds, and pumpkin seed oil used in combination with saw palmetto may be particularly beneficial in supporting prostate health.
5. Anti-Diabetic Effects
Animal studies suggest that pumpkin seeds may help improve insulin regulation and help prevent diabetic complications by decreasing oxidative stress.
6. Benefits for Postmenopausal Women
Pumpkin seed oil is rich in natural phytoestrogens and studies suggest it may lead to a significant increase in good “HDL” cholesterol along with decreases in blood pressure, hot flashes, headaches, joint pains and other menopausal symptoms in postmenopausal women.
7. Heart and Liver Health
Pumpkin seeds, rich in healthy fats, antioxidants and fibers, may provide benefits for heart and liver health, particularly when mixed with flax seeds.
8. Tryptophan for Restful Sleep
Pumpkin seeds are a rich source of tryptophan, an amino acid (protein building block) that your body converts into serotonin, which in turn is converted into melatonin, the “sleep hormone.” Eating pumpkin seeds a few hours before bed, along with a carbohydrate like a small piece of fruit, may be especially beneficial for providing your body the tryptophan needed for your melatonin and serotonin production to help promote a restful night’s sleep.
9. Anti-Inflammatory Benefits
Pumpkin seed oil has been found to exhibit anti-inflammatory effects. One animal study even found it worked as well as the anti-inflammatory drug indomethacin in treating arthritis, but without the side effects.
What’s the Best Way to Consume Pumpkin Seeds?
In order to preserve the healthy fats present in the seeds, pumpkin seeds should be eaten raw. If you choose to purchase seeds from a bulk bin, make sure they smell fresh – not musty, spoiled or stale, which could indicate rancidity or the presence of fungal mycotoxins. Organic pumpkin seeds are preferred, as they will not be contaminated with pesticides or other harmful chemicals.
As of Tuesday, Health Canada will phase out a system of homegrown marijuana for a factory-style operation that will grow, package and distribute a variety of marijuana, the Toronto Star reported Sunday.
About 37,400 patients use medical marijuana, Health Canada says. That number is expected to rise to as many as 450,000 by 2024.
The sanctioned growers are required to raise the plants indoors and have vaults and security systems to prevent thefts of their products, which could be sold on the black market. One firm plans to initially produce 20 strains.
Recreational use of marijuana will still be banned.
Since June, 156 companies have applied for licenses. The first two were awarded last week.
Under the system being phased out, about 4,200 people were licensed to grow marijuana on their property for no more than two patients each. That type of cottage industry will now be banned. The Royal Canadian Mounted Police has charged such operations were fronts for illegal activity.
The price of legal weed is expected to soon undercut the stuff sold on the streets, where it goes for about $10 a gram, or about $280 an ounce. Health Canada projects the factory-grown marijuana will retail next year for about $7.60 a gram, or $215 an ounce. Within 10 years, industry revenues are projected to reach $1.3 billion a year.
Sophie Galarneau, a senior Health Canada official, said she expects competition to eventually get the price down to $3 a gram, or about $85 an ounce.