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Category: computing – Page 665

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.

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Some researchers continue to insist that simulating neuroscience with computers is the way to go. Others, like me, view these efforts as doomed to failure because we do not believe consciousness is computable. Our basic argument is that brains integrate and compress multiple components of an experience, including sight and smell – which simply can’t be handled in the way today’s computers sense, process and store data.

Brains don’t operate like computers

Living organisms store experiences in their brains by adapting neural connections in an active process between the subject and the environment. By contrast, a computer records data in short-term and long-term memory blocks. That difference means the brain’s information handling must also be different from how computers work.

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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 —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.

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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

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The smallest pieces of nature—individual particles like electrons, for instance—are pretty much interchangeable. An electron is an electron is an electron, regardless of whether it’s stuck in a lab on Earth, bound to an atom in some chalky moon dust or shot out of an extragalactic black hole in a superheated jet. In practice, though, differences in energy, motion or location can make it easy to tell two electrons apart.

One way to test for the similarity of particles like electrons is to bring them together at the same time and place and look for interference—a that arises when particles (which can also behave like waves) meet. This interference is important for everything from fundamental tests of quantum physics to the speedy calculations of quantum computers, but creating it requires exquisite control over particles that are indistinguishable.

With an eye toward easing these requirements, researchers at the Joint Quantum Institute (JQI) and the Joint Center for Quantum Information and Computer Science (QuICS) have stretched out multiple photons—the quantum particles of light—and turned three distinct pulses into overlapping quantum waves. The work, which was published recently in the journal Physical Review Letters, restores the interference between photons and may eventually enable a demonstration of a particular kind of quantum supremacy—a clear speed advantage for computers that run on the rules of quantum physics.

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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, promise many innovations in the electronics and computer industries, as well as in the development of quantum computers. The thin surface layer can almost without resistance, resulting in less than traditional materials. This makes them of particular interest for .

Furthermore, in topological insulators, the electronic —i.e. the electron-mediated conversion of electrical energy into heat—can be reduced and controlled. Researchers of the University of Basel, the Swiss Nanoscience Institute (SNI) and the Istanbul Technical University have now been able to experimentally verify and demonstrate exactly how the transition from energy to heat through friction behaves—a process known as dissipation.

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Three years ago, an outfit called Electric GT (EGT), led by Eric Hutchison, hit the green tech radar by converting a 1978 Ferrari 308 GTS to an electric car. Out went the mid-mounted 2.9-liter V8 making 280 horsepower and 181 pound-feet of torque, in went 48 lithium-ion batteries powering three AC51 HPEVS electric motors that cumulatively produced 465 hp and 330 lb-ft. The company’s relocated from San Diego to Chatsworth, California, and is back on the scopes at Green Car Reports with what it calls an Electric Crate Motor. The innovation repackages the ICE crate motor methodology into a system making EV conversions easier for the weekend enthusiast. EGT promises a plug-and-play system with “high performance and near zero maintenance,” having packaged its one- and two-motor systems into a “motor block” and peripherals that look just like an internal combustion engine.

The block includes everything necessary for the swap to electric except the batteries and the mounting bracket, meaning” motor(s), controller(s), charger(s), sensors, relays and computer systems.” EGT has already designed a number of mounting brackets, and can design others to custom specs. According to the web site, the package is “pre-engineered, pre-built, and pre-tested,” so installation takes five steps: Bolt in the block, install the wiring harness and cooling system, connect the AC and DC power leads with the OEM-level touch-safe connectors, and route the internal cooling pump to a heat exchanger. Voila, silent running. Every e-crate motor comes with an installation manual, EGT provides tech support, and auxiliaries like electric AC compressors and heaters can be optioned.

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Physicists and materials scientists have developed a compact optical device containing vertically stacked metasurfaces that can generate microscopic text and full-color holograms for encrypted data storage and color displays. Yueqiang Hu and a research team in Advanced Design and Manufacturing for Vehicle Body in the College of Mechanical and Vehicle Engineering in China implemented a 3D integrated metasurface device to facilitate miniaturization of the optical device. Using metasurfaces with ultrathin and compact characteristics, the research team designed optical elements by engineering the wavefront of light at the subwavelength scale. The metasurfaces possessed great potential to integrate multiple functions into the miniaturized optoelectronic systems. The work is now published on Light: Science & Applications.

Since existing research on multiplexing in the 2-D plane remains to fully incorporate capabilities of metasurfaces for multi-tasking, in the present work, the team demonstrated a 3D integrated metasurface device. For this, they stacked a hologram metasurface on a monolithic Fabry-Pérot (FP) cavity-based color filter microarray to achieve simultaneous cross-talk, polarization-independent and highly efficient full-color holography and microprint functions. The dual function of the device outlined a new scheme for data recording, security, encryption and information processing applications. The work on 3D integration can be extended to establish flat multi-tasking optical systems that include a variety of functional metasurface layers.

Metasurfaces open a new direction in optoelectronics, allowing researchers to design optical elements by shaping the wavefront of electromagnetic waves relative to size, shape and arrangement of structures at the subwavelength. Physicists have engineered a variety of metasurface-based devices including lenses, polarization converters, holograms and orbital angular momentum generators (OAM). They have demonstrated the performance of metasurface-based devices to even surpass conventional refractive elements to construct compact optical devices with multiple functions. Such devices are, however, withheld by shortcomings due to a reduced efficiency of plasmonic nanostructures, polarization requirements, large crosstalk and complexity of the readout for multiwavelength and broadband optical devices. Research teams can therefore stack 3D metasurface-based devices with different functions in the vertical direction to combine the advantages of each device.

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