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Quantum mechanics is one of the most successful theories of natural science, and although its predictions are often counterintuitive, not a single experiment has been conducted to date of which the theory has not been able to give an adequate description.

Along with colleagues at bigQ (Center for Macroscopic Quantum States—a Danish National Research Foundation Center of Excellence), center leader Prof. Ulrik Lund Andersen is working on understanding and utilizing macroscopic quantum effects.

“The prevailing view among researchers is that quantum mechanics is a universally valid theory and therefore also applicable in the macroscopic day-to-day world we normally live in. This also means that it should be possible to observe quantum phenomena on a large scale, and this is precisely what we strive to do in the Danish National Research Foundation Center of Excellence bigQ,” says Lund Andersen.

The universe is getting messy. Like a glass shattering to pieces or a single wave crashing onto the shore, the universe’s messiness can only move in one direction – toward more chaos and disorder. But scientists think that, at least for a single electron or the simplest quantum computer, they may be able to turn back time, and restore order to chaos. This doesn’t mean we’ll be visiting with dinosaurs or Napoleon any time soon, but for physicists, the idea that time can run backward at all is still a pretty big deal.

Normally, the universe’s trend toward disorder is a fundamental law: the second law of thermodynamics. It says more formally that any system can only move from more to less ordered, and that the chaos or disorder of a system – its entropy – can never decrease. But an international team of scientists led by researchers at the Moscow Institute of Physics and Technology think they may have discovered a loophole.

Quantum simulation plays an irreplaceable role in diverse fields, beyond the scope of classical computers. In a recent study, Keren Li and an interdisciplinary research team at the Center for Quantum Computing, Quantum Science and Engineering and the Department of Physics and Astronomy in China, U.S. Germany and Canada. Experimentally simulated spin-network states by simulating quantum spacetime tetrahedra on a four-qubit nuclear magnetic resonance (NMR) quantum simulator. The experimental fidelity was above 95 percent. The research team used the quantum tetrahedra prepared by nuclear magnetic resonance to simulate a two-dimensional (2-D) spinfoam vertex (model) amplitude, and display local dynamics of quantum spacetime. Li et al. measured the geometric properties of the corresponding quantum tetrahedra to simulate their interactions. The experimental work is an initial attempt and a basic module to represent the Feynman diagram vertex in the spinfoam formulation, to study loop quantum gravity (LQG) using quantum information processing. The results are now available on Communication Physics.

Classical computers cannot study large quantum systems despite successful simulations of a variety of physical systems. The systematic constraints of classical computers occurred when the linear growth of quantum system sizes corresponded to the exponential growth of the Hilbert Space, a mathematical foundation of quantum mechanics. Quantum physicists aim to overcome the issue using quantum computers that process information intrinsically or quantum-mechanically to outperform their classical counterparts exponentially. In 1982, Physicist Richard Feynman defined quantum computers as quantum systems that can be controlled to mimic or simulate the behaviour or properties of relatively less accessible quantum systems.

In the present work, Li et al. used nuclear magnetic resonance (NMR) with a high controllable performance on the quantum system to develop simulation methods. The strategy facilitated the presentation of quantum geometries of space and spacetime based on the analogies between nuclear spin states in NMR samples and spin-network states in quantum gravity. Quantum gravity aims to unite the Einstein gravity with quantum mechanics to expand our understanding of gravity to the Planck scale (1.22 × 10¹⁹ GeV). At the Planck scale (magnitudes of space, time and energy) Einstein gravity and the continuum of spacetime breakdown can be replaced via quantum spacetime. Research approaches toward understanding quantum spacetimes are presently rooted in spin networks (a graph of lines and nodes to represent the quantum state of space at a certain point in time), which are an important, non-perturbative framework of quantum gravity.

From tiny snowflakes to the jagged fork of a lightning bolt, it’s not hard to find examples of fractals in the natural world. So it might come as a surprise that, until now, there have remained some places these endlessly repeating geometrical patterns have never been seen.

Physicists from MIT have now provided the first known example of a fractal arrangement in a quantum material.

The patterns were seen in an unexpected distribution of magnetic units called ‘domains’, which develop in a compound called neodymium nickel oxide — a rare earth metal with extraordinary properties.

Exactly one century ago, on an evening in 1918, renowned physicist Albert Einstein wrote down an idea in the pages of his notebook. That idea could be the key to solving one of the grandest and most elusive mysteries in all of physics: that of dark matter and dark energy. Together they make up over 95% of the universe, working invisibly to envelop galaxies and at once continuing to expand our universe at an accelerating rate, driving us away from nearby star systems and into a future with great divides.

The idea Einstein wrote about was an adjustment to general relativity where empty space would become negative mass moving under the influence of gravity. These negative masses would populate interstellar space. But this idea emerged as a way to explain the cosmological constant — or what Einstein referred to as his life’s greatest mistake. At the time when the cosmological constant was created, it was a widely accepted belief that the universe was static. That is, it was neither expanding nor contracting. But if this was true then something had to be countering gravity to prevent the universe from collapsing in on itself. Thus the cosmological constant with antigravity properties was born.

Today we understand the universe is not static and that it continues to expand, and so the cosmological constant has taken on a new meaning. It represents dark energy within the Lambda CDM, our current and most accepted model of the universe. The newest theory on dark matter and dark energy does not contradict the standard model and instead builds off of the note Einstein made to himself all those years ago.

An international team of scientists from Australia, Japan and the United States has produced a prototype of a large-scale quantum processor made of laser light.

Based on a design ten years in the making, the processor has built-in scalability that allows the number of quantum components—made out of light—to scale to extreme numbers. The research was published in Science today.

Quantum computers promise fast solutions to hard problems, but to do this they require a large number of quantum components and must be relatively error free. Current quantum processors are still small and prone to errors. This new design provides an alternative solution, using light, to reach the scale required to eventually outperform classical computers on important problems.

Harry Potter’s ‘invisibility cloak’ appears closer to reality as Canadian camouflage manufacturer Hyperstealth Biotechnology has applied for patents on its ‘Quantum Stealth’ material.

The ‘inexpensive and paper-thin’ technology works by bending light around a target to either alter its position or make it vanish altogether, leaving only the background visible. It is touted to be able to obscure the positions of heavy artillery, ground troops or even entire buildings from certain viewpoints.

Continue reading “‘Invisibility cloak’ that could hide tanks and troops looks closer to reality” »

Topological insulators are innovative materials that conduct electricity on the surface, but act as insulators on the inside. Physicists at the University of Basel and the Istanbul Technical University have begun investigating how they react to friction. Their experiment shows that the heat generated through friction is significantly lower than in conventional materials. This is due to a new quantum mechanism, the researchers report in the scientific journal Nature Materials.

Thanks to their unique electrical properties, topological insulators promise many innovations in the electronics and computer industries, as well as in the development of quantum computers. The thin surface layer can conduct electricity almost without resistance, resulting in less heat than traditional materials. This makes them of particular interest for electronic components.

“Our measurements clearly show that at certain voltages there is virtually no heat generation caused by electronic friction.” — Dr. Dilek Yildiz

Scientists have managed to send a record-breaking amount of data in quantum form, using a strange unit of quantum information called a qutrit.

The news: Quantum tech promises to allow data to be sent securely over long distances. Scientists have already shown it’s possible to transmit information both on land and via satellites using quantum bits, or qubits. Now physicists at the University of Science and Technology of China and the University of Vienna in Austria have found a way to ship even more data using something called quantum trits, or qutrits.

Qutrits? Oh, come on, you’ve just made that up: Nope, they’re real. Conventional bits used to encode everything from financial records to YouTube videos are streams of electrical or photonic pulses than can represent either a 1 or a 0. Qubits, which are typically electrons or photons, can carry more information because they can be polarized in two directions at once, so they can represent both a 1 and a 0 at the same time. Qutrits, which can be polarized in three different dimensions simultaneously, can carry even more information. In theory, this can then be transmitted using quantum teleportation.