Direct observation of an ion moving through a Bose-Einstein condensate identifies the effect of ion-atom collisions on charge transport in an ultracold gas.
When you expose mobile electrical charges in a medium to an electrical field, current flows. The charges are accelerated by the field, but collisions within the medium give rise to a kind of friction effect, which limits the velocity of the charges and thus the current. This universal concept, called diffusive transport, describes a large range of media, such as metallic conductors, electrolytic solutions, and gaseous plasmas. But in a quantum system, such as a superconductor or a superfluid, other collective effects can influence the transport through the medium. Now, a group led by Florian Meinert and Tilman Pfau both of the University of Stuttgart, Germany, have carried out charge-transport experiments with a single ion traversing a Bose-Einstein condensate (BEC), which is a quantum gas of cold neutral atoms [1]. The precise tracking of the ion shows that the transport is diffusive and reveals the character of the ion-atom collisions.
Martinus J.G. Veltman, a Dutch theoretical physicist who was awarded the Nobel Prize for work that explained the structure of some of the fundamental forces in the universe, helping to lay the groundwork for the development of the Standard Model, the backbone of quantum physics, died on Jan. 4 in Bilthoven, the Netherlands. He was 89.
His death was announced by the National Institute for Subatomic Physics in the Netherlands. No cause was given.
There are four known fundamental forces in the universe: gravity, electromagnetism, the strong force that bonds subatomic particles together, and the weak force that is responsible for particle decay. Since the discovery of the last two forces in the first half of the 20th century, physicists have looked for a unified theory that could account for the existence of all four.
A team of researchers affiliated with several institutions in China has used drones to create a prototype of a small airborne quantum network. In their paper published in the journal Physical Review Letters, the researchers describe sending entangled particles from one drone to another and from a drone to the ground.
Computer scientists, physicists and engineers have been working over the last several years toward building a usable quantum network —doing so would involve sending entangled particles between users and the result would be the most secure network ever made. As part of that effort, researchers have sent entangled particles over fiber cables, between towers and even from satellites to the ground. In this new effort, the researchers have added a new element—drones.
To build a long-range quantum network, satellites appear to be the ideal solution. But for smaller networks, such as for communications between users in the same city, another option is needed. While towers can be of some use, they are subject to weather and blockage, intentional or otherwise. To get around this problem, the researchers used drones to carry the signals.
Scientists at the Institute of Physics of the University of Tartu have found a way to develop optical quantum computers of a new type. Central to the discovery are rare earth ions that have certain characteristics and can act as quantum bits. These would give quantum computers ultrafast computation speed and better reliability compared to earlier solutions. The University of Tartu researchers Vladimir Hizhnyakov, Vadim Boltrushko, Helle Kaasik and Yurii Orlovskii published the results of their research in the scientific journal Optics Communications.
While in ordinary computers, the units of information are binary digits or bits, in quantum computers the units are quantum bits or qubits. In an ordinary computer, information is mostly carried by electricity in memory storage cells consisting of field-effect transistors, but in a quantum computer, depending on the type of computer, the information carriers are much smaller particles, for example ions, photons and electrons. The qubit information may be carried by a certain characteristic of this particle (for example, spin of electron or polarization of photon), which may have two states. While the values of an ordinary bit are 0 or 1, also intermediate variants of these values are possible in the quantum bit. The intermediate state is called the superposition. This property gives quantum computers the ability to solve tasks, which ordinary computers are unable to perform within reasonable time.
The most recent observations at both quantum and cosmological scales are casting serious doubts on our current models. For instance, at quantum scale, the latest electronic hydrogen proton radius measurement resulted in a much smaller radius than the one predicted by the standard model of particles physics, which now is off by 4%. At cosmological scale, the amount of observations regarding black holes and galactic formation heading in the direction of a radically different cosmological model, is overwhelming. Black holes have shown being much older than their hosting galaxies, galactic formation is much younger than our models estimates, and there is evidence of at least 64 black holes aligned with respect to their axis of rotation, suggesting the presence of a large scale spatial coherence in angular momentum that is impossible to predict with our current models. Under such scenario, it should not fall as a surprise the absence of a better alternative to unify quantum theory and relativity, and thus connect the very small to the very big, than the idea that the universe is actually a neural network. And for this reason, a theory of everything would be based on it.
As explained in Targemann’s interview to Vanchurin on Futurism, the work of Vanchurin, proposes that we live in a huge neural network that governs everything around us.
“it’s a possibility that the entire universe on its most fundamental level is a neural network… With this respect it could be considered as a proposal for the theory of everything, and as such it should be easy to prove it wrong”. Vitaly Vanchurin The idea was born when he was studying deep machine learning. He wrote the book “Towards a theory of machine learning”, in order to apply the methods of statistical mechanics to study the behavior of neural networks, and he saw that in certain limits the learning (or training) dynamics of neural networks is very similar to the quantum dynamics. So, he decided to explore the idea that the physical world is a neural network.
The incredible physics behind quantum computing. Watch the newest video from Big Think: https://bigth.ink/NewVideo. Learn skills from the world’s top minds at Big Think Edge: https://bigth.ink/Edge. ——————————————————————————— While today’s computers—referred to as classical computers—continue to become more and more powerful, there is a ceiling to their advancement due to the physical limits of the materials used to make them. Quantum computing allows physicists and researchers to exponentially increase computation power, harnessing potential parallel realities to do so.
Quantum computer chips are astoundingly small, about the size of a fingernail. Scientists have to not only build the computer itself but also the ultra-protected environment in which they operate. Total isolation is required to eliminate vibrations and other external influences on synchronized atoms; if the atoms become ‘decoherent’ the quantum computer cannot function.
“You need to create a very quiet, clean, cold environment for these chips to work in,” says quantum computing expert Vern Brownell. The coldest temperature possible in physics is-273.15 degrees C. The rooms required for quantum computing are-273.14 degrees C, which is 150 times colder than outer space. It is complex and mind-boggling work, but the potential for computation that harnesses the power of parallel universes is worth the chase.
Check Chris Bernhardt’s book “Quantum Computing for Everyone (MIT Press)” at http://amzn.to/3nSg5a8 ——————————————————————————— TRANSCRIPT:
MICHIO KAKU: Years ago, we physicists predicted the end of Moore’s Law, which says a computer power doubles every 18 months. But we also, on the other hand, proposed a positive program—perhaps molecular computers, quantum computers can take over when silicon power is exhausted. In fact, already we see a slowing down of Moore’s Law. Computer power simply cannot maintain its rapid exponential rise using standard silicon technology. The two basic problems are heat and leakage. That’s the reason why the age of silicon will eventually come to a close. No one knows when, but as I mentioned we already now can see the slowing down of Moore’s Law, and in 10 years it could flatten out completely. So what’s the problem? The problem is that a Pentium chip today has a layer almost down to 20 atoms across, 20 atoms across. When that layer gets down to about five atoms across, it’s all over. You have two effects, heat. The heat generated will be so intense that the chip will melt. You can literally fry an egg on top of the chip, and the chip itself begins to disintegrate. And second of all, leakage. You don’t know where the electron is anymore. The quantum theory takes over. The Heisenberg Uncertainty Principle says you don’t know where that electron is anymore, meaning it could be outside the wire, outside the Pentium chip or inside the Pentium chip. So there is an ultimate limit set by the laws of thermodynamics and set by the laws of quantum mechanics, as to how much computing power you can do with silicon.
VERN BROWNELL: I refer to today’s computers as classical computers. They compute largely in the same way they have for the past 60 or 70 years, since John Von Neumann and others invented the first electronic computers back in the ‘40s. And we’ve had amazing progress over those years. Think of all the developments there’ve been on the hardware side and the software side over those 60 or 70 years and how much energy and development has been put into those areas. And we’ve achieved marvelous things with that classical computing environment, but it has its limits too, and people sometimes ask, “Why would we need any more powerful computers?” These applications, these problems that we’re trying to solve, are incredibly hard problems and aren’t well-suited for the architecture of classical computing. So I see quantum computing as another set of tools, another set of resources for scientists, researchers, computer scientists, programmers, to develop and enhance some of these capabilities to really change the world in a much better way than we’re able to today with classical computers.
A new study, led by a theoretical physicist at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), suggests that never-before-observed particles called axions may be the source of unexplained, high-energy X-ray emissions surrounding a group of neutron stars.
First theorized in the 1970s as part of a solution to a fundamental particle physics problem, axions are expected to be produced at the core of stars, and to convert into particles of light, called photons, in the presence of a magnetic field.
Axions may also make up dark matter —the mysterious stuff that accounts for an estimated 85 percent of the total mass of the universe, yet we have so far only seen its gravitational effects on ordinary matter. Even if the X-ray excess turns out not to be axions or dark matter, it could still reveal new physics.
Conventionally speaking, there is a single physicist named Sean Carroll at Caltech, busily puzzling over the nature of the quantum world. In the theoretical sense, though, he may be one of a multitude, each existing in its own world. And there’s nothing unique about him: Every person, rock, and particle in the universe participates in an endlessly branching reality, Carroll argues, splitting into alternate versions whenever an event occurs that has multiple possible outcomes.
He is well aware that this idea sounds like something from a science fiction movie (and it doesn’t help that he was an advisor on Avengers: Endgame). But these days, a growing number of his colleagues take the idea of multiple worlds seriously. In his new book, Something Deeply Hidden, Carroll proposes that the “Many Worlds Interpretation” is not only a reasonable way to make sense of quantum mechanics, it is the most reasonable way to do so.
Prominent supporters of the Many Worlds Interpretation include physicists David Deutsch at Oxford University and Max Tegmark at MIT. If they are right, our intuitive sense of how reality works is profoundly wrong. Then again, some other researchers think that the Many Worlds way of looking at quantum mechanics is misguided, unproductive, or even downright absurd.
By adding some magnetic flair to an exotic quantum experiment, physicists produced an ultra-stable one-dimensional quantum gas with never-before-seen “scar” states – a feature that could someday be useful for securing quantum information.
As the story goes, the Greek mathematician and tinkerer Archimedes came across an invention while traveling through ancient Egypt that would later bear his name. It was a machine consisting of a screw housed inside a hollow tube that trapped and drew water upon rotation. Now, researchers led by Stanford University physicist Benjamin Lev have developed a quantum version of Archimedes’ screw that, instead of water, hauls fragile collections of gas atoms to higher and higher energy states without collapsing. Their discovery is detailed in a paper published today (January 142021) in Science.
As the story goes, the Greek mathematician and tinkerer Archimedes came across an invention while traveling through ancient Egypt that would later bear his name. It was a machine consisting of a screw housed inside a hollow tube that trapped and drew water upon rotation. Now, researchers led by Stanford University physicist Benjamin Lev have developed a quantum version of Archimedes’ screw that, instead of water, hauls fragile collections of gas atoms to higher and higher energy states without collapsing. Their discovery is detailed in a paper published Jan. 14 in Science.
“My expectation for our system was that the stability of the gas would only shift a little,” said Lev, who is an associate professor of applied physics and of physics in the School of Humanities and Sciences at Stanford. “I did not expect that I would see a dramatic, complete stabilization of it. That was beyond my wildest conception.”
Along the way, the researchers also observed the development of scar states—extremely rare trajectories of particles in an otherwise chaotic quantum system in which the particles repeatedly retrace their steps like tracks overlapping in the woods. Scar states are of particular interest because they may offer a protected refuge for information encoded in a quantum system. The existence of scar states within a quantum system with many interacting particles—known as a quantum many-body system—has only recently been confirmed. The Stanford experiment is the first example of the scar state in a many-body quantum gas and only the second ever real-world sighting of the phenomenon.
As explained in 
