In ordinary three-dimensional liquids, such particles execute a type of random motion known as Brownian motion.#science
But in two-dimensional liquids, the team was able to demonstrate that the Brownian motion is overlaid on large-scale collective motions. (.... atoms in 2-D liquids can travel for long distances before effectively 'forgetting' their initial positions. ) This collective motion was previously believed to only occur in 2-D solids.
What role did the #Dialogo actually play in the ongoing cosmological/astronomical debate in the seventeenth century? The real answer is, given its reputation, surprisingly little. In reality Galileo was totally out of step with the actual debate that was taking place around 1630. Driven by…http://voxday.blogspot.com/2020/01/galileo-had-it-coming.html
...in reality, three-body equations became much more difficult to solve.... if all three objects are of a comparable size and distance from the center point, a power struggle develops and the whole system is thrown into chaos. When chaos happens, it becomes impossible to track the bodies' movements using regular math.#science
Stone and Professor Nathan Leigh at Chile's La Universidad de Concepción relied on discoveries from the past two centuries, namely that unstable three-body systems will eventually expel one of the trio, and form a stable binary relationship between the two remaining bodies. This relationship was the focus of their study.
"When we compared our predictions to computer-generated models of their actual movements, we found a high degree of accuracy,"
While the researchers stress that their findings do not represent an exact solution to the three-body problem, statistical solutions are still extremely helpful in that they allow physicists to visualize complicated processes.
"Take three black holes that are orbiting one another. Their orbits will necessarily become unstable and even after one of them gets kicked out, we're still very interested in the relationship between the surviving black holes," explained Stone. This ability to predict new orbits is critical to our understanding of how these—and any three-body problem survivors—will behave in a newly-stable situation.
According to research from the Stratospheric Observatory for Infrared Astronomy (SOFIA), magnetic fields play a strong role in shaping these galaxies.#science
However, this intuitive nature of entropy does not necessarily apply to the microscopic world. Physicists have therefore reinterpreted the second law by giving it a statistical twist: Entropy indeed increases, but there is a non-null probability that it may sometimes decrease.#science
Fluctuation theorems (FTs) quantified this probability with precision, and the issue has practical interest in regard to the operation of nanoscale machines. FTs were proposed for the first time in an article published in 1993.
An article published recently in the same journal shows that one consequence of FTs is thermodynamic uncertainty relations, which involve fluctuations in the values of thermodynamic quantities such as heat, work and power.
"The physical origins of thermodynamic uncertainty relations were obscure until now. Our study shows they can be derived from FTs,"
Thermodynamic uncertainty relations were discovered in 2015...
The mathematical structure of these relations resembles that of Heisenberg's uncertainty principle, but they have nothing to do with quantum physics; they are purely thermodynamic. "The nature of thermodynamic uncertainty relations has never been very clear," Landi said. "Our main contribution was to show that they derive from FTs. We believe that FTs describe the second law of thermodynamics more generally and that thermodynamic uncertainty relations are a consequence of FTs."
According to Landi, this generalization of the second law of thermodynamics handles thermodynamic quantities as entities that can fluctuate, though not arbitrarily, since they must obey certain symmetries. "There are several fluctuation theorems," he said. "We found a special class of FTs and focused on them as cases of mathematical symmetry. In this manner, we transformed our problem into a mathematical problem. Our main result was a theorem of probability theory."
MOOSE is a high-level pluggable architecture that allows engineers and scientists to leverage the power of large supercomputers when trying to solve complex real-world problems, even if they have little or no knowledge of parallel programming techniques. Since its release in 2014, it has consistently grown in popularity, and it is now used by several research teams worldwide.mooseframework.org
"With the right conditions, planets could be formed even in harsh environments, such as around a black hole,"#science
"Our calculations show that tens of thousands of planets with 10 times the mass of the Earth could be formed around 10 light-years from a black hole,"
Researchers at the University of Waterloo have developed a method that could pave the way to establishing universal standards for measuring the performance of quantum computers.#science
The new method, called cycle benchmarking, allows researchers to assess the potential of scalability and to compare one quantum platform against another.
"Cycle benchmarking is the first method for reliably checking if you are on the right track for scaling up the overall design of your quantum computer," said Wallman. "These results are significant because they provide a comprehensive way of characterizing errors across all quantum computing platforms."
Researchers ...have recently developed a new technique to measure mechanical motion using simultaneous electromechanical amplification and cooling processes.#science
“we are using these mechanical systems to efficiently convert signals between the microwave domain and the optical domain. The conversion of signals between these two disparate frequency bands"
"Our research came about for two reasons,... First...enabling the conversion of signals between microwave and optical domains, (which is important for networking future quantum computers, or to build the equivalent of the quantum internet). ... (Second, they) wanted to figure out a way to measure this motion beyond the quantum limit (which is difficult to achieve by using back-action evading measurement)”
Mechanical oscillators are used in several physics subfields, for instance when conducting research investigating quantum mechanics on larger scales, quantum limited force sensing and quantum information.
"In this work, we demonstrated a nearly noiseless measurement of the position of a mechanical oscillator, which has been difficult to achieve with previously used techniques like back-action evading measurement or external parametric amplification,"
In the future, the method for measuring mechanical motion introduced by this team of researchers could open up new horizons for physics research and pave the way for the development of new tools, including force-sensing technology and techniques to link quantum computers. In addition, their method could be ideal for characterizing mechanical oscillators prepared in even more exotic quantum states, such as superposition states or cat states, a long-sought goal in the physics field.
Hello. I like #physics, #astronomy and #philosophy.
I think that everybody can joke about everything.
Also I like watching #anime and reading #books. I love #imageboards.
And I am looking for a pen pal. I mean, to chat using real letters. ✉️
In 1961, physicist Eugene Wigner proposed a provocative thought experiment....#science
The scenario has long remained an interesting thought experiment. But does it reflect reality? Scientifically, there has been little progress on this until very recently, when Časlav Brukner ... showed that, under certain assumptions, Wigner's idea can be used to formally prove that measurements in quantum mechanics are subjective to observers.
We have now for the first time performed this test experimentally...
The theory, however, is based on a few assumptions. These include that the measurement outcomes are not influenced by signals travelling above light speed and that observers are free to choose what measurements to make. That may or may not be the case.
Another important question is whether single photons can be considered to be observers....
This experiment therefore shows that, at least for local models of #quantum mechanics, we need to rethink our notion of objectivity. The facts we experience in our macroscopic world appear to remain safe, but a major question arises over how existing interpretations of quantum mechanics can accommodate subjective facts.
Some physicists see these new developments as bolstering interpretations that allow more than one outcome to occur for an observation, for example the existence of parallel universes in which each outcome happens. Others see it as compelling evidence for intrinsically observer-dependent theories such as Quantum Bayesianism , in which an agent's actions and experiences are central concerns of the theory. But yet others take this as a strong pointer that perhaps quantum mechanics will break down above certain complexity scales.
Clearly these are all deeply philosophical questions about the fundamental nature of reality. Whatever the answer, an interesting future awaits.
Now our new paper,...has come to a conclusion that may unleash a crisis in #cosmology—if confirmed. We show that the shape of the universe may actually be curved rather than flat, as previously thought—with a probability larger than 99%. In a curved universe, no matter which direction you travel in, you will end up at the starting point—just like on a sphere. Though the universe has four dimensions, including time.#science
The result was based on recent measurements of the Cosmic Microwave Background, the light left over from the Big Bang, collected by the Planck Satellite.
Once we assume that the universe is curved, the Planck data is essentially in disagreement with all other datasets. This all boils down to a real crisis for cosmology, as we say in our paper. For these reasons, cosmologists are cautious—and many of them prefer to attribute the results to a statistical fluke that will resolve when new data from future experiments are available.
It is certainly possible that we turn out to be wrong. But there is one main reason, in our opinion, why this anomaly should not be merely discarded. In particle physics, a discovery should reach an accuracy of at least five "sigmas" to be accepted by the community. Here we are slightly above three sigmas, so we are clearly below this acceptance level. But while the standard model of particle physics is based on known and proven physics, the standard cosmological model is based on unknown physics.
At the moment, the physical evidence for the three pillars of cosmology—dark matter, dark energy (which causes the universe to expand at an accelerated rate) and inflation—comes solely from cosmology...But they are not expected either in the standard model of particle physics or in the theory of general relativity... Instead, these substances belong to the area of unknown physics. Nobody has ever seen either dark matter, dark energy or inflation—in the laboratory or elsewhere.
So while an anomaly in particle physics can be regarded as a hint that we may need to invent completely new physics, an anomaly in cosmology should be regarded as the only way we have to shed light on completely unknown physics.
Therefore, the most interesting result of our paper is not that the universe appears to be curved rather than flat, but the fact that it may force us to rearrange the pieces of the cosmic puzzle in a completely different way.
"Our understanding of these fundamental constants has defined the universe as we now know it. When our understanding of laws becomes more precise, our definition of the universe also becomes more precise, which leads to new insights and discoveries."#science
"The large majority of the universe is made up of dark energy and dark matter. And we believe it is dark energy that is 'blowing up the balloon.' Dark energy is pushing things away from each other. Gravity, which attracts objects toward each other, is the stronger force at the local level, which is why some galaxies continue to collide. But at cosmic distances, dark energy is the dominant force."
"Our results show the maturity reached in the last decade by the relatively recent field of high-energy astrophysics. The analysis that we have developed paves the way for better measurements in the future using the Cherenkov Telescope Array, which is still in development and will be the most ambitious array of ground-based high-energy telescopes ever."
"What we know is that gamma-ray photons from extragalactic sources travel in the universe toward Earth, where they can be absorbed by interacting with the photons from starlight," Ajello said. "The rate of interaction depends on the length that they travel in the universe. And the length that they travel depends on expansion. If the expansion is low, they travel a small distance. If the expansion is large, they travel a very large distance. So the amount of absorption that we measured depended very strongly on the value of the Hubble Constant. What we did was turn this around and use it to constrain the expansion rate of the universe."
With the design of these quantum information networks come new theoretical challenges, given that it is necessary to establish optimised automated information treatment protocols to work with quantum data, in the same way as current communication networks automatically manage information.#science
UAB researchers have had to deal with one of these challenges for the first time: the problem with sorting data from a quantum systems network according to the state in which they were prepared. The researchers have devised an optimal procedure that can identify clusters of identically prepared quantum systems.
The protocol developed by researchers at the UAB shows a natural connection to an archetypical use case of classical machine learning: clustering data samples according to whether they share a common underlying probability distribution. The problem is similar to how a classical computer discerns the origin of different sounds captured simultaneously by a microphone placed on the street. The computer can recognise patterns and discern a conversation, traffic, and a street musician. However, unlike soundwaves, identifying patterns in quantum data is much more challenging, since a mere observation only provides partial information and irretrievably degrades the data in the process.
In current quantum field theory, causality is typically defined by the vanishing of field commutators for spacelike separations. Two researchers at the University of Massachusetts and Universidade Federal Rural in Rio de Janeiro have recently carried out a study discussing and synthesizing some of the key aspects of causality in quantum field theory. Their paper, published in Physical Review Letters, is the result of their investigation of a theory of quantum gravity commonly referred to as "quadratic gravity."
"Like the ingredients of the standard model, quadratic gravity is a renormalizable quantum field theory, but it has some peculiar properties," John Donoghue, one of the researchers who carried out the study, told Phys.org. "The small violation of causality is the most important of these and our goal was to understand this better. In the process, we realized that some of the insights are of more general interest ....
So far, most theoretical discussions about causality, specifically the "arrow of time," have asserted that the laws of physics do not have any preference for the flow of time. However, this particular assumption is not applicable to quantum physics, where a direction for causal effects is present.
"The various factors of i in the quantization procedures are related to the direction of causal action, which leads to the 'arrow of causality' in quantum physics," Donoghue explained. "This connection is not discussed very often."
"Perhaps the most important implication of our study is that we collected evidence of causal uncertainty due to spacetime fluctuations that can arise in a quantum theory of gravity," Menezes said. "This would provide us with a deep intuitive understanding of the origins of causality."
...researchers ...have created a nanostructured surface capable of performing on-the-fly mathematical operations on an input image. This discovery could boost the speed of existing imaging processing techniques and lower energy usage. The work enables ultrafast object detection and augmented reality applications
Prior research has shown that it is likely that black holes that form due to the death of a star cannot exceed 40 solar masses—more massive stars would have more nuclei which suggests they would wind up as pairs of unstable supernovae. But researchers working at the #LIGO and #VIRGO projects have found evidence of black holes that are bigger than the 40 solar mass threshold. Some in the field have proposed that such black holes could come about due to random collisions and mergers with other black holes—but the idea has not been fully developed until now
A few days after the joint meeting of November 6, Lorentz sent another telegram to Einstein, confirming the news [L4]. On November 7, 1919, the Einstein legend began.
Thus the birth of the Einstein legend can be pinpointed at November 7, 1919, when the London Times broke the news.
From that day until his death, not one single year passed without his name appearing in that paper, often in relation to science, more often in relation to other issues.
Через несколько дней после совместного заседания, состоявшегося 6 ноября, Лоренц направил Эйнштейну еще одну телеграмму, подтверждавшую предыдущую [L4]. Так, с 7 ноября 1919 г. начала создаваться легенда об Эйнштейне.
Таким образом, можно точно определить, когда родилась легенда об Эйнштейне — это произошло 7 ноября 1919 г. после публикации в «Times».
С того дня не проходило ни одного года, чтобы его имя не упоминалось в этой газете в связи с его научной работой, но чаще в связи с чем-то другим.
Einstein's science and the salesmanship of the press were necessary but not sufficient conditions for the creation of the legend, however. Compare, for example, the case of Einstein with the one and only earlier instance in which a major discovery in physics had created a worldwide sensation under the influence of newspapers. That was the case of Roentgen and the X-rays he discovered in 1895. It was the discovery, not the man, that was at the center of attention. Its value was lasting and it has never been forgotten by the general public, but its newsworthiness went from a peak into a gentle steady decline.#massmedia #metaprogramming #past #physics #religion #revision #revolution #science #time #timespace #1919cc
The essence of Einstein's unique position goes deeper and has everything to do, it seems to me, with the stars and with language. A new man appears abruptly, the 'suddenly famous Doctor Einstein.' He carries the message of a new order in the universe. He is a new Moses come down from the mountain to bring the law and a new Joshua controlling the motion of heavenly bodies. He speaks in strange tongues but wise men aver that the stars testify to his veracity. Through the ages, child and adult alike had looked with wonder at stars and light. Speak of such new things as X-rays or atoms and man may be awed. But stars had forever been in his dreams and his myths. Their recurrence manifested an order beyond human control. Irregularities in the skies—comets, eclipses—were omens, mainly of evil. Behold, a new man appears. His mathematical language is sacred yet amenable to transcription into the profane: the fourth dimension, stars are not where they seemed to be but nobody need worry, light has weight, space is warped. He fulfills two profound needs in man, the need to know and the need not to know but to believe. The drama of his emergence is enhanced (though this to me seems secondary) by the coincidence—itself caused largely by the vagaries of war—between the meeting of the joint societies and the first annual remembrance of horrid events
of the recent past which had caused millions to die, empires to fall, the future to be uncertain. The new man who appears at that time represents order and power. He becomes the Θειοσ ανηρ, the divine man, of the twentieth century.
И все же как сама теория Эйнштейна, так и умение газетчиков подать товар лицом были необходимым, но не достаточным условием создания легенды. Сравните, к примеру, «случай Эйнштейна» с другим крупным открытием в физике, которое произвело сенсацию во всем мире благодаря прессе. Я говорю о Рентгене и лучах, открытых им в 1895 г. Тогда в центре внимания было само открытие, а отнюдь не личность ученого. Значимость открытия сохранилась, но его освещение в печати после достижения пика постепенно сошло на нет.
Причина уникального положения Эйнштейна имеет глубокие корни и, на мой взгляд, несомненно, связана со звездами и с языком. Вдруг появляется новая фигура, «внезапно прославившийся доктор Эйнштейн». Он несет откровение о новом строении Вселенной. Он — новый Моисей, сошедший с горы, чтобы установить свой закон; он — новый Иисус, которому подвластно движение небесных тел. Он говорит на непонятном языке, но волхвы уверяют, что звезды подтверждают его правоту. Веками все люди, и дети и взрослые, с восхищением смотрели на звезды и Солнце. Поведайте человечеству о таких открытиях, как рентгеновское излучение или атомы, и оно будет благоговеть перед вами. Что же говорить о звездах, которые всегда были в легендах и мечтах человечества! Их движение свидетельствовало о том, что они не подчиняются воле человека. Непонятные явления в небесах — кометы, затмения — почти всегда считались дурными предзнаменованиями. И вот явился новый человек. Его математический язык таинствен, но его можно растолковать и профанам: четвертое измерение, звезды не там, где нам кажется, но волноваться нечего, свет имеет вес, пространство искривлено. В нем воплощены два сокровенных желания человека — знать и верить, не зная. Драматический эффект его появления усиливается (хотя мне этот фактор кажется второстепенным) и совпадением, вызванным войной, — дата совместного заседания Королевских обществ пришлась на первую годовщину окончания страшных событий близкого прошлого, когда погибли миллионы, пали империи, будущее представлялось, как в тумане. А новый человек, появившийся в это время, олицетворяет силу и порядок. Он Θειοσ ανηρ — богоравный человек XX в.