May 8, 2024
How quantum physics could ‘revolutionise everything’
Posted by Dan Breeden in categories: computing, quantum physics
From unhackable communication networks to powerful computers, quantum technology promises huge advances.
From unhackable communication networks to powerful computers, quantum technology promises huge advances.
Popular Summary.
Most currently used quantum neural network architectures have little-to-no inductive biases, leading to trainability and generalization issues. Inspired by a similar problem, recent breakthroughs in classical machine learning address this crux by creating models encoding the symmetries of the learning task. This is materialized through the usage of equivariant neural networks whose action commutes with that of the symmetry.
In this work, we import these ideas to the quantum realm by presenting a general theoretical framework to understand, classify, design, and implement equivariant quantum neural networks. As a special implementation, we show how standard quantum convolutional neural networks (QCNN) can be generalized to group-equivariant QCNNs where both the convolutional and pooling layers are equivariant under the relevant symmetry group.
Ever since superconductivity was discovered in the early 1900s, it has both captivated and mystified scientists. Superconductors conduct electricity with virtually zero resistance, allowing for highly efficient transmission of electrical currents. Among other uses, they create the strong magnetic fields we depend on for medical imaging with MRI machines.
The first known superconductor, mercury, only works when the temperature dips just below-450 F. Copper-containing materials called cuprates were found in the ’80s to become superconductors at warmer temperatures, though still inconveniently cold — closer to-200 F. Understanding how these so-called high-temperature superconductors work could eventually lead to ones that can operate in less frigid conditions.
One potential hallmark of high-temperature superconductors has remained purely theoretical, until now. A team of scientists, including several from the U.S. Department of Energy’s (DOE) Argonne National Laboratory, has observed an elusive state of matter called quantum spin nematic. The study, which was published in the journal Nature (“Quantum spin nematic phase in a square-lattice iridate”), used the Advanced Photon Source (APS), a DOE Office of Science user facility at Argonne that also happens to use superconductors. The results lend insight on both high-temperature superconductivity and some of the physics involved in quantum computing.
Superradiant atoms offer a groundbreaking method for measuring time with an unprecedented level of precision. In a recent study published by the scientific journal Nature Communications, researchers from the University of Copenhagen present a new method for measuring the time interval, seconds, that overcomes some of the limitations that even today’s most advanced atomic clocks encounter. This advancement could have broad implications in areas such as space exploration, volcanic monitoring, and GPS systems.
The second, which is the most precisely defined unit of measurement, is currently measured by atomic clocks in different places around the world that together tell us what time it is. Using radio waves, atomic clocks continuously send signals that synchronize our computers, phones, and watches.
Oscillations are the key to keeping time. In a grandfather clock, these oscillations are from a pendulum’s swinging from side to side every second, while in an atomic clock, it is a laser beam that corresponds to an energy transition in strontium and oscillates about a million billion times per second.
Researchers at AMOLF, working alongside colleagues from Germany, Switzerland, and Austria, have realized a new type of metamaterial through which sound waves flow in an unprecedented fashion. It provides a novel form of amplification of mechanical vibrations, which has the potential to improve sensor technology and information processing devices.
This metamaterial is the first instance of a so-called ‘bosonic Kitaev chain’, which gets its special properties from its nature as a topological material. It was realized by making nanomechanical resonators interact with laser light through radiation pressure forces. The discovery, which is published on March 27 in the renowned scientific journal Nature, was achieved in an international collaboration between AMOLF, the Max Planck Institute for the Science of Light, the University of Basel, ETH Zurich, and the University of Vienna.
The ‘Kitaev chain’ is a theoretical model that describes the physics of electrons in a superconducting material, specifically a nanowire. The model is famous for predicting the existence of special excitations at the ends of such a nanowire: Majorana zero modes. These have gained intense interest because of their possible use in quantum computers.
In this talk at Mindfest 2024, Hartmut Neven proposes that conscious moments are generated by the formation of quantum superpositions, challenging traditional views on the origins of consciousness. Please consider signing up for TOEmail at https://www.curtjaimungal.org.
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String theory could provide a theory of everything for our universe—but it entails 10500 (more than a centillion) possible solutions. AI models could help to find the right one.
Tiny little threads whizzing through spacetime and vibrating incessantly: this is roughly how you can imagine the universe, according to string theory. The various vibrations of the threads generate the elementary particles, such as electrons and quarks, and the forces acting among them.
Researchers at the Universities of Melbourne and Manchester have invented a breakthrough technique for manufacturing highly purified silicon that brings powerful quantum computers a big step closer.
Illinois may be on the verge of securing the largest technology project in its history—what is being labeled a “$20 billion, 150-acre quantum computing campus,” potentially anchored by Silicon Valley startup PsiQuantum, according to Crain’s Chicago Business. PsiQuantum, hot off an announcement that its receiving $600 million to build a manufacturing site in Australia, is reportedly considering two Chicago-area locations for the project, the business journal reports.
The proposed sites, the former U.S. Steel plant on the South Side and the former Texaco refinery in Lockport, are both under final review, with a decision expected soon. This initiative is part of a broader vision by Governor J.B. Pritzker’s administration, which pundits are referring to a modern-day Manhattan Project, to position Illinois as a leader quantum computing.
Quantum computing leverages the principles of quantum mechanics to process information much faster than classical machines for certain computational problems. Quantum devices could potentially transform everything from cancer research to climate modeling. PsiQuantum aims to use a photonic quantum approach to develop a fault-tolerant quantum computer that could be commercially viable.
A year after all but ruling out the possibility, a pair of theoretical physicists from Japan and the Netherlands have found quantum entanglement has something fundamentally in common with the physics that drives steam engines, dries your socks, and may even keep the arrow of time pointed in one direction.
This universal property, if indeed it exists as they suggest, would govern all transformations between entangled systems and give physicists a way to measure and compare entanglement beyond counting qubits – and know their limits of manipulating entangled pairs.
Quantum entanglement, the tendency for the quantum fuzziness of different objects to mathematically merge, is a fundamental part of quantum computing along with superposition. When particles, atoms, or molecules are entangled, knowing something about one tells us something of the other.