The “spooky action at a distance” that once unnerved Einstein may be on its way to being as pedestrian as the gyroscopes that currently measure acceleration in smartphones.
Quantum entanglement significantly improves the precision of sensors that can be used to navigate without GPS, according to a new study in Nature Photonics.
“By exploiting entanglement, we improve both measurement sensitivity and how quickly we can make the measurement,” said Zheshen Zhang, associate professor of electrical and computer engineering at the University of Michigan and co-corresponding author of the study. The experiments were done at the University of Arizona, where Zhang was working at the time.
There are high expectations that quantum computers may deliver revolutionary new possibilities for simulating chemical processes. This could have a major impact on everything from the development of new pharmaceuticals to new materials. Researchers at Chalmers University have now, for the first time in Sweden, used a quantum computer to undertake calculations within a real-life case in chemistry.
“Quantum computers could in theory be used to handle cases where electrons and atomic nuclei move in more complicated ways. If we can learn to utilize their full potential, we should be able to advance the boundaries of what is possible to calculate and understand,” says Martin Rahm, Associate Professor in Theoretical Chemistry at the Department of Chemistry and Chemical Engineering, who has led the study.
Within the field of quantum chemistry, the laws of quantum mechanics are used to understand which chemical reactions are possible, which structures and materials can be developed, and what characteristics they have. Such studies are normally undertaken with the help of super computers, built with conventional logical circuits. There is however a limit for which calculations conventional computers can handle. Because the laws of quantum mechanics describe the behavior of nature on a subatomic level, many researchers believe that a quantum computer should be better equipped to perform molecular calculations than a conventional computer.
Hydrogen, the most abundant element in the universe, is found everywhere from the dust filling most of outer space to the cores of stars to many substances here on Earth. This would be reason enough to study hydrogen, but its individual atoms are also the simplest of any element with just one proton and one electron. For David Ceperley, a professor of physics at the University of Illinois Urbana-Champaign, this makes hydrogen the natural starting point for formulating and testing theories of matter.
Ceperley, also a member of the Illinois Quantum Information Science and Technology Center, uses computer simulations to study how hydrogen atoms interact and combine to form different phases of matter like solids, liquids, and gases. However, a true understanding of these phenomena requires quantum mechanics, and quantum mechanical simulations are costly. To simplify the task, Ceperley and his collaborators developed a machine learning technique that allows quantum mechanical simulations to be performed with an unprecedented number of atoms. They reported in Physical Review Letters that their method found a new kind of high-pressure solid hydrogen that past theory and experiments missed.
“Machine learning turned out to teach us a great deal,” Ceperley said. “We had been seeing signs of new behavior in our previous simulations, but we didn’t trust them because we could only accommodate small numbers of atoms. With our machine learning model, we could take full advantage of the most accurate methods and see what’s really going on.”
Providing increased resistance to outside interference, topological qubits create a more stable foundation than conventional qubits. This increased stability allows the quantum computer to perform computations that can uncover solutions to some of the world’s toughest problems.
While qubits can be developed in a variety of ways, the topological qubit will be the first of its kind, requiring innovative approaches from design through development. Materials containing the properties needed for this new technology cannot be found in nature—they must be created. Microsoft brought together experts from condensed matter physics, mathematics, and materials science to develop a unique approach producing specialized crystals with the properties needed to make the topological qubit a reality.
Donald Hoffman interview on spacetime, consciousness, and how biological fitness conceals reality. We discuss Nima Arkani-Hamed’s Amplituhedron, decorated permutations, evolution, and the unlimited intelligence.
The Amplituhedron is a static, monolithic, geometric object with many dimensions. Its volume codes for amplitudes of particle interactions & its structure codes for locality and unitarity. Decorated permutations are the deepest core from which the Amplituhedron gets its structure. There are no dynamics, they are monoliths as in 2001: A Space Odyssey.
Background. 0:00 Highlights. 6:55 The specific limits of evolution by natural selection. 10:50 Don’s born in a San Antonio Army hospital in 1955 (and his parents’ background) 14:44 As a teenager big question he wanted answered, “Are we just machines?“ 17:23 Don’s early work as a vision researcher; visual systems construct. 20:43 Carlos’s 3-part series on Fitness-Beats-Truth Theorem.
Fitness-Beats-Truth Theorem. 22:29 Clarifications on FBT: Game theory simulations & math proofs. 24:20 What does he mean I can’t see reality? Fitness payoff functions don’t know about the truth… 28:23 Evolution shapes sensory systems to guide adaptive behavior… consider the virtual reality headset 32:45 FBT doesn’t include costs for extra bits of information processing 34:40 Joscha Bach’s “There are no colors in the universe”… though even light itself isn’t fundamental! 36:36 Map-territory relationship 40:27 Infinite regress, Godel’s Incompleteness Theorem 42:27 Erik Hoel’s causal emergence theory 45:40 Don’s take on causality: there are no causal powers within spacetime What’s Beyond Spacetime? 50:50 Nima Arkani-Hamed’s Amplituhedron 53:00 What percentage of physicists would agree spacetime is doomed? 56:00 Amplituhedron a static, monolithic, geometric object with many dimensions… 59:23 Ties to holographic principle, Ads-CFT correspondence 1:03:13 Quantum error correction 1:05:23 James Gates’ adinkra animations linking electromagnetism & electron-like objects The Unlimited Intelligence 1:08:30 Does Don still meditate 3 hours every day? 1:11:30 “We’re here for the ride…” 1:12:27 All my theories are trivial, there’s an unlimited intelligence that transcends 1:14:00 Carlos meanders on meditation 1:15:50 “You can’t know the truth, but you can be the truth” 1:17:43 Explore-Exploit Tradeoff (foraging strategy) 1:19:15 “You’re absolutely knocking on the right doors here”… our 4D spacetime for some reason essential for consciousness 1:21:10 Why this world, with these symbols, this interface? 1:22:20 “My guess, one of the cheaper headsets” Conscious Realism 1:24:40 Precise, mathematical model of consciousness… the end of Cantor’s infinities 1:28:30 Fusions of Consciousness paper… bridges between interactions of conscious agents/Markovian dynamics → decorated permutations → the Amplituhedron → spacetime 1:35:20 In a meta way, did Don choose the highest fitness path for his career? 1:39:10 “Don’t believe my theory, not the final word” 1:41:00 Where to find more of Don’s work 🚩Links to Donald Hoffman & More 🚩 “Do we see reality as it is?” (Ted Talk 2015) • Do we see reality…
“Symmetry Does Not Entail Veridicality” lecture (Hoffman 2017) • Don Hoffman — “Sy…
Interfacial superconductivity and the quantum anomalous Hall effect have been developed by layer-by-layer material fabrication.
A new method created by Pritzker School of Molecular Engineering (PME) researchers can help determine the origin of electronic states in designed materials.
Assistant Professor Shuolong Yang and his colleagues created a method for better understanding magnetic topological insulators, which have unique surface properties that could make them useful in quantum information science technologies.
A giant orbital magnetic moment exists in graphene quantum dots, according to new work by physicists at the University of California Santa Cruz in the US. As well as being of fundamental interest for studying systems with relativistic electrons – that is those travelling at near-light speeds – the work could be important for quantum information science since these moments could encode information.
Graphene, a sheet of carbon just one atom thick, has a number of unique electronic properties, many of which arise from the fact that it is a semiconductor with a zero-energy gap between its valence and conduction bands. Near where the two bands meet, the relationship between the energy and momentum of charge carriers (electrons and holes) in the material is described by the Dirac equation and resembles that of a photon, which is massless.
These bands, called Dirac cones, enable the charge carriers to travel through graphene at extremely high, “ultra-relativistic” speeds approaching that of light. This extremely high mobility means that graphene-based electronic devices such as transistors could be faster than any that exist today.
Graphene is found to exhibit a magnetoresistance dwarfing that of all known materials at room temperature—a behavior that may lead to new magnetic sensors and help decipher the physics of strange metals.
One might expect that, two decades after its discovery, graphene would have exhausted its potential for surprises. But the thinnest, strongest, most conductive of all materials has now added another record to its tally. A collaboration that includes graphene’s codiscoverer and Nobel laureate Andre Geim of the University of Manchester, UK, reports that graphene can have a room-temperature magnetoresistance—a magnetic-field-induced change in electrical resistivity—that’s 100 times larger than that of any known material [1]. Graphene’s giant magnetoresistance could lead to novel magnetic-field sensors but also offer an experimental window into exotic quantum regimes of electrical conduction that might be related to the mysterious “strange metals.”
Magnetoresistance, which occurs both in bulk materials and multilayer structures, found a killer app in magnetic-field sensors such as those used to read data from magnetic memories. Researchers have long been interested in the limits of this phenomenon, which has led to discoveries of “giant,” “colossal,” and “extraordinary” forms of magnetoresistance. The associated materials exhibit resistivity changes of up to 1,000,000% when exposed to magnetic fields of several teslas (T). The largest effects, however, require extremely low temperatures that can only be reached with impractical liquid-helium cooling systems.
Even if you are not a quantum physicist, you will most likely have heard of Schrödinger’s famous cat. Erwin Schrödinger came up with the feline that can be alive and dead at the same time in a thought experiment in 1935. The obvious contradiction—after all, in everyday life we only ever see cats that are either alive or dead—has prompted scientists to try to realize analogous situations in the laboratory. So far, they have managed to do so using, for instance, atoms or molecules in quantum mechanical superposition states of being in two places at the same time.
At ETH, a team of researchers led by Yiwen Chu, professor at the Laboratory for Solid State Physics, has now created a substantially heavier Schrödinger cat by putting a small crystal into a superposition of two oscillation states. Their results, which have been published this week in the journal Science, could lead to more robust quantum bits and shed light on the mystery of why quantum superpositions are not observed in the macroscopic world.
In Schrödinger’s original thought experiment, a cat is locked up inside a metal box together with a radioactive substance, a Geiger counter and a flask of poison. In a certain time-frame—an hour, say—an atom in the substance may or may not decay through a quantum mechanical process with a certain probability, and the decay products might cause the Geiger counter to go off and trigger a mechanism that smashes the flask containing the poison, which would eventually kill the cat.
Quantum teleportation is a technique allowing the transfer of quantum information between two distant quantum objects, a sender and a receiver, using a phenomenon called quantum entanglement as a resource.
The unique feature of this process is that the actual information is not transferred by sending quantum bits (qubits) through a communication channel connecting the two parties; instead, the information is destroyed at one location and appears at the other one without physically traveling between the two. This surprising property is enabled by quantum entanglement, accompanied by the transmission of classical bits.
There is a deep interest in quantum teleportation nowadays within the field of quantum communications and quantum networks because it would allow the transfer of quantum bits between network nodes over very long distances, using previously shared entanglement.
