Ultrasmall engines bend second law of thermodynamics Quantum entanglement may help single atoms drive heat machines BY ANDREW GRANT 7:00AM, MARCH 8, 2016 please log in to view this image THE LAWS OF HEAT GO SMALL Car engines and batteries run because of the second law of thermodynamics, which appears to work, with just a little bending, for ultrasmall engines in the quantum realm as well. MARY KATE MCDEVITT When French engineer Sadi Carnot calculated the maximum efficiency of a heat engine in 1824, he had no idea what heat was. In those days, physicists thought heat was a fluid called caloric. But Carnot, later lauded as a pioneer in establishing the second law of thermodynamics, didn’t have to know those particulars, because thermodynamics is insensitive to microscopic details. Heat flows from hot to cold regardless of whether it consists of a fluid or, as it turns out, the collective motion of trillions of trillions of molecules. Thermodynamics, the laws and equations governing energy and its usefulness to do work, concerns itself only with the big picture. It’s a successful approach. As thermodynamics requires, energy is always conserved (the first law), and when it flows from hot to cold it can do work, limited by the generation of disorder, or entropy (the second law). These laws dictate everything from the miles per gallon a car engine gets to the battery life of a smartphone. They help physicists better understand black holes and why time moves forward but not backward (SN: 7/25/15, p. 15). Yet the big picture approach, considering the forest rather than the trees, has made physicists wonder if thermodynamics holds at all scales. Would it work if an engine consisted of three molecules rather than the typical trillion trillion? In the realm of the very small, governed by the quirky rules of quantum mechanics, perhaps the thermodynamic code is not so rigid. please log in to view this image MARY KATE MCDEVITT “Thermodynamics was designed for big stuff,” says Janet Anders, a theoretical physicist at the University of Exeter in England. “We haven’t really integrated thermodynamics with quantum mechanics.” Over the last few decades, physicists have gradually explored heat flow at the quantum level, intrigued by the possibility of finding violations of thermodynamics’ second law. So far, the second law has held strong. But new precision experimental techniques are allowing physicists to explore the quantum foundations of thermodynamics more fully. Testing the limits set by theorists, researchers are building tiny engines, some powered by a single atom, and measuring the devices’ feeble oomph. Even if physicists can’t break the thermodynamic rules, recent evidence suggests ways to bend them — especially by exploiting the way quantum entanglement weaves together the fates of a few particles. Techniques used in processing quantum information could prove useful for squeezing extra energy out of miniature engines, for instance. These lessons could help scientists build nanomachines that harvest heat and use it to deliver medicine inside the body, or help reduce energy loss in the tiny components of traditional computers. Quantum engines Any future practical applications of this work will depend on understanding how basic thermodynamic principles operate at ultrasmall scales. It goes back to statistics, says University College London quantum theoretical physicist Jonathan Oppenheim. If the trillion trillion gas molecules in a steam engine were represented by that many coins, then the result of flipping all those coins would be a homogenous mixture of heads and tails, the equivalent of stable temperature and maximum entropy. That’s why steam engines always follow the rules. But flip three minicoins inside a tiny quantum engine and all three could easily land on heads, as if all the fast molecules stayed in one compartment rather than mixing with the other — a violation of the second law. Experiments over the years had suggested that if the second law of thermodynamics does break down at small scales, the violation is not very drastic. Last year, Oppenheim and colleagues got more specific, publishing a detailed analysis in the Proceedings of the National Academy of Sciences. Their results indicate that not only does the second law actually hold at the quantum scale, it is also more demanding. Rather than analyzing entropy directly, Oppenheim’s team looked at how much energy a system has available to do work, a quantity called free energy. In our macroscopic world, the amount of free energy depends only on a system’s temperature and entropy. But by zooming in toward smaller and smaller collections of particles, the researchers found that they had to take into account several more varieties of free energy. Every one of them decreases over time. In other words, the second law requires adherence to even more rules at the quantum level. Recent experiments have made it clear that attempts to circumvent the second law at any scale are doomed. In the Dec. 31 Physical Review Letters, Jonne Koski, a physicist at Aalto University in Finland, and colleagues created the laboratory equivalent of the heat-manipulating “demon” conjured by Scottish physicist James Clerk Maxwell in 1867. SN Online: 12/1/15). Koski’s electronic demon failed because of its reliance on information about individual particles. The connection between information and thermodynamics dates back to 1929. That’s when Hungarian physicist Leo Szilard dug deeper into Maxwell’s thought experiment and drew up a blueprint for exploiting information about particles, such as their position and velocity, to perform tasks. Szilard’s work demonstrated that in physics, information isn’t merely a stock quote or a baseball player’s batting average — it’s physical. More than three decades later, IBM physicist Rolf Landauer showed that Szilard’s approach came with a cost. Maxwell’s demon may capitalize on its knowledge about one particle, Landauer said, but the demon must use up the energy it gained when it scrubs that information from its finite memory and turns its attention to the next particle. Erasing information costs energy. That’s why the sophisticated demonic circuit failed to circumvent the second law. Information is clearly important for understanding thermodynamics, and it’s also downright essential for making sense of the stranger parts of quantum mechanics. Tiny bits of matter can essentially exist in two places at once, a phenomenon called superposition. Two or more particles can be wrangled into what’s known as an entangled state, intricately linking the particles’ properties regardless of the distance between them. Many physicists are trying to exploit superposition, quantum entanglement and other quantum trickery to perform information-heavy tasks that are impossible under the rules of classical physics. Researchers envision supersecure communication networks and quantum computers that exploit entangled photons or ions to solve complex problems with ease (SN: 11/20/10, p. 22). But information means much more than just exchanging and processing 1s and 0s. As a result, physicists pondering quantum computing and communication have turned their attention to thermodynamics. They’ve begun asking whether properties such as entanglement could also offer an advantage in converting heat into work. In the October–December 2015 Physical Review X, a European team demonstrated that a system of several entangled particles stores more usable energy than the same particles without quantum connections. The advantage, which quickly disappears as the number of particles increases, boils down to the notion that information is a resource. Entangled particles essentially provide information for free, because knowing something about one particle reveals something about its entangled partners (SN: 1/9/16, p. 9). Even though the second law holds strong, says study coauthor Marcus Huber, the ability to exploit information from quantum effects “also helps you to do things that you couldn’t do classically.” Information advantage Obtaining information at a discount may enable technology that bends the second law and outperforms the best life-size engines. “What we can hope for are machines that run faster, refrigerators that get cooler or batteries that store more or charge faster,” says Huber, a quantum information theorist at the University of Geneva. Huber compares the challenge ahead to playing a game, much like the one Carnot played in the 19th century. Carnot essentially turned dials controlling variables such as temperature and pressure until he had squeezed the maximum efficiency out of a steam engine. Today’s physicists have different goals — perhaps creating a microscopic refrigerator to cool their instruments to unfathomably low temperatures. To achieve such goals, physicists plan to turn the dials for variables like entanglement and see what happens. Soon scientists may be able to start playing those games with engines exploiting quantum effects in the lab. German researchers took a step toward that goal in October by building a heat engine consisting of a single atom. Johannes Roßnagel, a quantum physicist at the University of Mainz, and colleagues built a cone-shaped enclosure around a calcium ion. After using a laser and electric field to heat up the ion to about one degree above absolute zero, the researchers measured the work performed by the ion as it exerted a subtle push toward the top of the cone. Story continues below graphic worked just as the laws of thermodynamics say it should, the researchers reported in a paper posted online at arXiv.org. Adjusting for the tiny weight of the ion, the power was comparable to that of a car engine, Roßnagel says. “It’s quite interesting to see that you can drive heat machines with a single atom,” he says. Despite the measureable power output of the single-ion engine, Roßnagel warns that nano-sized engines for practical use are decades away at best. Instead, the usefulness of quantum thermo-dynamics will probably happen under the hood of other technologies. Some researchers have their eyes on the multi-billion-dollar computer chip industry. In the drive to build ever-faster computers, engineers keep shrinking transistors to pack more and more onto chips. The transistors, some just tens of nano-meters wide, tend to leak electrons and heat up. That heat ruins the energy efficiency of the computer and damages components. Quantum thermodynamics could help physicists learn tricks to reduce the amount of wasted heat or perhaps even harvest it with small devices inside the computer. Heat management is even more crucial for physicists seeking to build practical quantum computers. Such a device needs to operate at extremely low temperatures to exploit quantum effects and potentially outperform traditional computers. Next, Roßnagel and his colleagues plan to chill their single atom until it’s capable of maintaining delicate quantum states including superposition and entanglement. Such an experiment would put Huber’s theoretical results to the test and expose the potential of adjusting those “quantumness” knobs to better exploit heat to do work. A few contrarians in the physics community say that such experiments could finally violate the vaunted second law of thermodynamics. But don’t bet on it. Early 20th century English astrophysicist Arthur Eddington is still looking good with his prediction that any theory attempting to defy the second law will “collapse in deepest humiliation.” But he didn’t say anything about moving the goalposts a bit.
Is there a FIFTH fundamental force? Large Hadron Collider results hint at bizarre new particle that doesn't fit with laws of physics In December, data suggested a particle six times heavier than Higgs It would not be described by Standard Model of particle physics More collisions will start next month, April 2016, to collect more data Experts expect confirmation or refutation of its existence in summer By ABIGAIL BEALL FOR MAILONLINE PUBLISHED: 11:15, 9 March 2016 | UPDATED: 11:26, 9 March 2016 The first signs of a particle heavier than the Higgs boson has been seen at the Large Hadron Collider (LHC). Unexplained by current models, its existence might lead to the discovery of a whole new set of particles and possibly even a fifth fundamental force. But the first results are not enough to confirm the particle exists, and more measurements still need to be taken when the LHC begins to fire up again next month. please log in to view this image +5 Two of the detectors, ATLAS and CMS, were searching for new physics by counting particle decays that ended up in two photons, and found a potential new particle. If it turns out to be real, and not a blip, this would be a huge discovery. Two high-energy photons whose energy, shown in red, was measured in the CMS is illustrated In data produced last December at the LHC in Geneva, two separate measurements found what looked like a particle six time heavier than the Higgs boson. If it turns out to be real, and not just a blip in the measurements, this would be a huge discovery. 'It would be something completely beyond the Standard Model, and the tip of an iceberg of a large new set of particles,' Professor John Ellis, theoretical physicist at Kings College London told MailOnline, 'if it exists!' THE ELUSIVE PARTICLE Two of the detectors at the Large Hadron Collider - ATLAS and CMS - were searching for new physics by counting particle decays that ended up in two photons. Measuring photons is a way of detecting new physics because photons are easy to detect and physicists know what to expect in terms of results from background events. When particles decay into photons, they release energy equivalent to their mass multiplied by the speed of light squared. The measurements saw photons with a combined energy of 750 GeV, making the potential particle six times heavier than the Higgs boson. If it turns out to be real, and not just a blip in the measurements, this would be a huge discovery. 'It would be something completely beyond the Standard Model, and the tip of an iceberg of a large new set of particles, if it exists!', the researchers said. Two of the detectors, ATLAS and CMS, were searching for new physics by counting particle decays that ended up in two photons. Measuring photons is a good method for detecting new physics because photons are easy to detect and physicists know what to expect in terms of results from background events. They saw photons with a combined energy of 750 GeV. When particles decay into photons, they release energy equivalent to their mass multiplied by the speed of light squared. We’re all familiar with Einstein’s most famous equation, and this observation is it in action. This means the particle that produced these photons is an as yet unknown with this exact amount of energy in the form of its mass. ‘It weighs about 750 GeV, corresponding to about six times heavier than the Higgs boson, and almost 800 times heavier than the proton,’ said Ellis. It was a similar 'bump' that gave the first hints to the Higgs boson. But the difference now is that the existence of the Higgs boson had already been predicted. This new particle, if it exists, has not been predicted by the Standard Model, so would open up physicists to a whole new unexplored world and could lead to the discovery of a new set of particles. please log in to view this image +5 In December last year the two observations, in the ATLAS and CMS detectors, hinted at a new particle six times heavier than the Higgs boson. The LHC will start making more collisions next month, April 2016, and experts can expect confirmation or refutation in the summer please log in to view this image +5 When particles decay into photons, they release energy equivalent to their mass multiplied by the speed of light squared. The measurements saw photons with a combined energy of 750 GeV, about six times heavier than the Higgs boson, something that has not been predicted by the current theory describing particle physics The Standard Model claims everything in the universe is made from the most basic building blocks called fundamental particles, that are governed by four forces: gravity, electromagnetic, weak nuclear and strong nuclear. The forces work over different ranges and have different strengths. This new particle, if it exists, would not fit into the description given by the Standard Model and so would lead to a whole new area of particle physics for them to explore. Some have suggested it might even lead to the discovery of a fifth fundamental force. This development is exciting because the Standard Model has left some questions unanswered for years, so scientists are keen to break free of it and find new theories. It can't explain gravity, for example, because it is incompatible with our best explanation of how gravity works - general relativity, nor does it explain dark matter particles. STANDARD MODEL OF PARTICLE PHYSICS AND WHY THE FIND IS SO EXCITING The Standard Model says everything in the universe is made from the most basic building blocks called fundamental particles, that are governed by four forces: gravity, electromagnetic, weak nuclear and strong nuclear. please log in to view this image +5 The Higgs boson, named after professor Higgs, shown, was discovered in 2012 and is an essential component of the Standard Model The forces work over different ranges and have different strengths. This new particle, if it exists, would not fit into the description given by the Standard Model and so would lead to a whole new area of particle physics. Some have suggested it might even lead to the discovery of a fifth fundamental force. This development is exciting because the Standard Model has left some questions unanswered for years, so scientists are keen to break free of it and find new theories. It can't explain gravity, for example, because it is incompatible with our best explanation of how gravity works - general relativity, nor does it explain dark matter particles. The quantum theory used to describe the small particles in the world, and the general theory of relativity used to describe the larger objects world, are also difficult to reconcile. Nobody has managed to make the two mathematically compatible in the context of the Standard Model. According to the Big Bang theory, matter and antimatter were created in equal amounts at the start of the universe and so they should have annihilated each other totally in the first second or so of the universe's existence. This means the cosmos should be full of light and little else. But because it isn't there must have been a subtle difference in the physics of matter and anti-matter that has left the universe with a surplus of matter and that makes up the stars we see, the planet we live on and ourselves. But the observations seen so far are not enough to confirm the existence of a particle. The quantum theory used to describe the small particles in the world, and the general theory of relativity used to describe the larger objects world, are also difficult to reconcile. Nobody has managed to make the two mathematically compatible in the context of the Standard Model. According to the Big Bang theory, matter and antimatter were created in equal amounts at the start of the universe and so they should have annihilated each other totally in the first second or so of the universe's existence. This means the cosmos should be full of light and little else. But because it isn't there must have been a subtle difference in the physics of matter and anti-matter that has left the universe with a surplus of matter and that makes up the stars we see, the planet we live on and ourselves. please log in to view this image +5 The detectors saw photons with a combined energy of 750 GeV. When particles decay into photons they release energy equivalent to their mass multiplied by the speed of light squared. This means the particle that decayed into them would have been about six times heavier than the Higgs boson But the observations seen so far are not enough to confirm the existence of a particle. The CERN physicists need to make sure the observations were not just down to chance, so it comes down to collecting much more data and waiting to see if the particle is spotted again. Some remain unconvinced. 'Indeed, I don't see yet statistically convincing bumps that would point to the existence of a new particle in the LHC data,' Professor Patrick Janot, working on the CMS detector at CERN told MailOnline. The LHC will start making more collisions next month, and the results that might confirm or refute the existence of this particle will be available by summer. 'You will hear solid statements in summer,' said Janot, 'when a lot more data than in 2015 are accumulated at 13 TeV.'
Large Hadron Collider casts doubt over bizarre new 'tetraquark': Follow-up tests fail to find any evidence for the weird particle Hints of a new particle with unusual properties were spotted at Fermilab But data from the LHC does not support the existence of this tetraquark New data currently being collected in the LHC might provide an answer By ABIGAIL BEALL FOR MAILONLINE Earlier this year, hints of a new particle with unusual properties were seen at Fermilab's Tevatron collider. Unlike normal particles, this one exotic particle was said to have contained four 'flavours' of quarks and antiquarks, making it a candidate for classification as a tetraquark. But in follow-up tests, researchers at the Large Hadron Collider have been unable to find any evidence of this particle, causing many to doubt its existence. please log in to view this image The new tetraquark, an arrangement of four quarks, the fundamental particles that build up the protons and neutrons inside atoms, was first announced in late February by physicists taking part in the DZero experiment at the Tevatron collider at Fermilab, Illinois The new tetraquark is an arrangement of four quarks - the fundamental particles that build up the protons and neutrons inside atoms. It was first announced in late February by physicists taking part in the DZero experiment at the Tevatron collider at Fermilab, Illinois. Physicists said a particle like this, if found to exist, would represent a new particle 'species', paralleling the ordinary subatomic particles known today. WHAT IS A QUARK? Quarks are elementary particles, the smallest particles we know to exist. When they combine they form compound particles known as hadrons. Quarks are said to have six ‘flavours’: Up, Down, Charm, Strange, Top and Bottom. Combinations of quarks within these flavours gives rise to the ‘larger’ particles. Groups of three quarks are known as baryons. An example of a baryon is a proton, which is made of two 'Up' quarks and a 'Down' quark. It would be the first tetraquark made up of four distinct flavours of quarks and antiquarks, bottom, strange, up, and down. But now scientists at the LHC said they have tried and failed to find evidence to confirm the particle, called X(5568), in their own data. 'We searched for the signal reported by DZero, using a roughly 20 times larger data sample,' lead author of the paper, LHCb physicist Vladimir Gligorov told MailOnline. 'We didn’t find any evidence for new tetraquarks, and, more specifically, we set an upper limit on their rate of production which is incompatible with the production rate reported by DZero.' This is bad news for supporters of the tetraquark because the LHC is more sensitive than the Tevatron at Fermilab. please log in to view this image +3 If the new tetraquark exists, it should theoretically show up at the LHC (pictured) and possibly at other colliders. 'You might be able to supply a conspiracy theory where it's only produced at the Tevatron and not at the LHC, but I think that's contrived,' Professor Browder from the University of Hawaii said THE RULES OF SUBATOMIC PHYSICS Atoms are usually made of protons, neutrons and electrons. These are made of smaller elementary particles, also known as fundamental particles - the smallest particles we know to exist. They are subdivided into two groups, the first being fermions, which are said to be the particles that make up matter. The second are bosons, the force particles that hold the others together. Protons are probably the best-known baryons. Within the group of fermions are subatomic particles known as quarks. When quarks combine in threes, they form compound particles known as baryons. Sometimes, quarks interact with corresponding anti-particles (such as anti-quarks), which have the same mass but opposite charges. When this happens, they form mesons. Mesons often turn up in the decay of heavy man-made particles, such as those in accelerators, reactors and cosmic rays. Mesons, baryons, and other kinds of particles that take part in interactions like these are called hadrons. 'I think the LHCb sensitivity is much better [than DZero's] so I would tend to doubt that this [tetraquark] result is real,' Professor Tom Browder of the University of Hawaii at Manoa told Scientific American. Professor Browder is a member of the Belle collider experiment in Japan. If the new tetraquark exists, it should theoretically show up at the LHC, and possibly at other colliders too. 'It's likely to be a statistical fluctuation,' Professor Browder said. 'You might be able to supply a conspiracy theory where it's only produced at the Tevatron and not at the LHC, but I think that's contrived.' Although Belle found the first known tetraquark in 2003, it is unlikely to spot X(5568), Browder said. The original study examined data obtained at the Tevatron collider, which is no longer running, over nearly ten years from 2002 to 2011. Scientists at the Tevatron's other experiment, CDF, are now looking at their own data now to look for the particle, but have not yet confirmed that they have the sensitivity required to find it. In principle they should be able to see it, Fermilab scientist and CDF member Jonathan Lewis said. 'But it's a detailed question. I can't make a definitive statement as to whether we can rule it in or out.' He also said the evidence from LHCb was strong evidence for the particle not existing. 'That's certainly a strong bit of contrary evidence that people need to consider,' Lewis says. 'I would wait and see.' http://www.dailymail.co.uk/sciencet...il-evidence-weird-particle.html#ixzz44OEjbs78 Follow us: @MailOnline on Twitter | DailyMail on Facebook
@sisu Earth’s hurricanes have nothing on this quasar Winds surrounding black hole are fastest on record BY CHRISTOPHER CROCKETT 3:02PM, MARCH 29, 2016 please log in to view this image WILD WHIRL Winds whipping around the black hole at the center of a quasar, such as the one illustrated here, are moving at roughly 20 percent of the speed of light, a new study reports. When visiting the center of a galaxy nicknamed J0230, pack a sturdy windproof jacket. There, you will encounter a galactic hurricane with winds whipping at about 200 million kilometers per hour. At that speed, nearly 20 percent of the speed of light, a trip around Earth would take just 0.7 seconds. These are the fastest known winds around a quasar, a blazing disk of detritus around a supermassive black hole, researchers report in the March 21 Monthly Notices of the Royal Astronomical Society. They’re about 625,000 times as fast as the highest sustained winds in any hurricane seen on Earth. These quasar winds get their speed from the intense radiation emitted by the disk, which glows as bright as roughly 22 trillion suns. The light comes from gases slamming together as they orbit a black hole with 2.2 billion times as much mass as the sun. Despite occupying a relatively tiny volume of space, the quasar can launch winds powerful enough to shape its entire home galaxy. Star-forming factories throughout the galaxy can get shut down as gases are flung into intergalactic space. Light from the quasar, which sits in the constellation Cetus, takes about 11 billion years to reach Earth. Its winds best those of the previous record holder, a quasar designated PG 2302+029, by about 14 million kilometers per hour.
