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Category: quantum physics – Page 941

Getting light in shape with metamaterials

A team built a specialized, layered structure with tiny metallic cavities that improves the light conversion efficiency by orders of magnitude.

ncident laser beam (top of the figure) illuminating an array of nanoscale gold resonators on the surface of a quantum well semiconductor

Artist’s rendering of an incident laser beam (top of the figure) illuminating an array of nanoscale gold resonators on the surface of a “quantum well” semiconductor (slab in figure). (A quantum well is a thin layer that can restrict the movement of electrons to that layer.) The incoming laser beam interacts with the array and the quantum wells and is converted into two new laser beams with different wavelengths. Changing the size, shape, and arrangement of the resonators can be used for beam focusing, beam steering, or control of the beam’s angular momentum. (Image: Sandia National Laboratories)

The new concept explained in the studies can open doors for advanced lasers for optical communications and efficient manufacturing. It can also support efforts to miniaturize optical components for high-speed computing, telecommunications, cameras, and quantum computing that will solve computational problems currently intractable by today’s supercomputers.

Improving computer graphics with quantum mechanics

Nice article; I do need to mention that more and more screen displays are moving to Q-Dot technology. So, computer graphics is being enriched in multiple ways by Quantum.

Caltech applied scientists have developed a new way to simulate large-scale motion numerically using the mathematics that govern the universe at the quantum level.

The , presented at the International Conference and Exhibition on Computer Graphics & Interactive Techniques (SIGGRAPH), held in Anaheim, California, from July 24–28, allows computers to more accurately simulate vorticity, the spinning motion of a flowing fluid.

A smoke ring, which seems to turn itself inside out endlessly as it floats along, is a complex demonstration of vorticity, and is incredibly difficult to simulate accurately, says Peter Schröder, Shaler Arthur Hanisch Professor of Computer Science and Applied and Computational Mathematics in the Division of Engineering and Applied Science.

Moving beyond semiconductors for next-generation electric switches

Computers use switches to perform calculations. A complex film with “quantum wells”—regions that allow electron motion in only two dimensions—can be used to make efficient switches for high-speed computers. For the first time, this oxide film exhibited a phenomenon, called resonant tunneling, in which electrons move between quantum wells at a specific voltage. This behavior allowed an extremely large ratio (about 100,000:1) between two states, which can be used in an electronic device as an ON/OFF switch to perform mathematical calculations (Nature Communications, “Resonant tunneling in a quantum oxide superlattice”).

Quantum wells

Efficient control of electron motion can be used to reduce the power requirements of computers. “Quantum wells” (QW) are regions that allow electron motion in only two dimensions. The lines (bottom) in the schematic show the probability of finding electrons in the structure. The structure is a complex oxide (top) with columns (stacked blue dots corresponding to an added element) where the electrons are free to move in only two dimensions. This is a special type of quantum well called a two-dimensional electron gas (2DEG). (Image: Ho Nyung Lee, Oak Ridge National Laboratory)

To meet our exponentially growing need for computing power without a corresponding jump in energy use, scientists need more efficient electronic versions of switches to perform calculations. Efficient switches need materials that switch between well-defined ON/OFF states. The results of this study could lead to a new class of energy-efficient electronics because these materials can ensure the electronic switches are ON or OFF. These electronic switches could lower power consumption in electronics enabling, for example, the development of high-speed supercomputers and cell phones with longer battery life.

Could Dark Energy Be Caused By A Reaction To What’s In The Universe? (Synopsis)

“Another very good test some readers may want to look up… is the Casimir effect, where forces between metal plates in empty space are modified by the presence of virtual particles.” –Gordon Kane

If you ask what the zero-point energy of space itself is, you can sum up all of the quantum fluctuations you can that arise in quantum field theory, and arrive at an absurd answer: 120 orders of magnitude greater than the observed. Yet if you assume that there’s an incredible cancellation and you get exactly zero, that removes the one thing our Universe needs to explain its expansion: dark energy.

Pixel-array quantum cascade detector paves the way for portable thermal imaging devices

Finally, portable thermal imaging devices could be here soon.

The primary source of infrared radiation is heat—the radiation produced by the thermal motion of charged particles in matter, including the motion of the atoms and molecules in an object. The higher the temperature of an object, the more its atoms and molecules vibrate, rotate, twist through their vibrational modes, the more infrared radiation they radiate. Because infrared detectors can be “blinded” by their own heat, high-quality infrared sensing and imaging devices are usually cooled down, sometimes to just a few degrees above absolute zero. Though they are very sensitive, the hardware required for cooling renders these instruments less-than-mobile, energy-inefficient and limits in-the-field applications.

A paper published this week in the journal Optics Express, from The Optical Society (OSA), describes a new type of portable, field-friendly, mid-infrared detector that operates at room temperature. Room-temperature operation, notes Andreas Harrer of the TU-Wien Center for Micro- and Nanostructures, Austria and the first author of the paper, “is essential for detectors to be energy-efficient enough for portable and handheld applications. We want to pave the way to an infrared-detection technology which is flexible in design and meets all requirements for compact integrated field-applicable detection systems.”

The type of instrument developed by Harrer and his colleagues is known as a quantum cascade detector, or QCD. A QCD is a high-speed detector composed of semiconductor devices that sense specific wavelengths of infrared light and convert that light into proportionate electrical signals. A unique aspect of the design described by Harrer and his colleagues is that it consists of an 8 × 8 array of pixels, each approximately 110 microns square. Tuning is achieved by specifically adjusting the well and the barrier dimensions to a wavelength of 4.3 microns.

Quantum dot photosensitizers as a new paradigm for photochemical activation

Interesting work on solar energy and Q-dot photosensitizers.

Interfacial triplet-triplet energy transfer is used to significantly extend the exciton lifetime of cadmium selenide nanocrystals in an experimental demonstration of their molecular-like photochemistry.

Photosensitizers are an essential component of solar energy conversion processes, in which they are used to generate the highly reactive excited states that enable energy conversion (e.g., photochemical upconversion).1, 2 Typically, molecular triplet photosensitizers are used for such applications, but to improve the solar energy conversion process, the identification and preparation of next-generation triplet photosensitizers is required. However, the design of such photosensitizers—suitable for solar energy conversion and photocatalytic applications—remains a challenge.3

Novel state of matter: Observation of a quantum spin liquid

Excellent article on improving crystalized formations & usage.

According to conventional understanding, if the interactions are isotropic (where all spin directions are possible), this phenomenon can occur if the spins are arranged in triangular geometries and the interactions between them are antiferromagnetic favouring antiparallel alignment of the spins. For three atoms forming the corners of a triangle, the electronic spin of one atom cannot simultaneously be oriented antiparallel to those on both the other two atoms. In real materials that contain triangular units coupled by antiferromagnetic interactions this “frustration” can prevent the spins from coming to rest in a particular orientation even at absolute zero temperature, instead they move collectively like atoms in a liquid. By contrast, ferromagnetic interactions do not give rise to frustration in isotropic magnets because mutually parallel alignment of the spins can always occur. For these reasons, only a few isotropic materials have been proposed as spin liquid candidates.

Monocrystals with complex magnetic interactions

Now a team headed by Prof. Bella Lake has produced and investigated the first monocrystals of calcium-chromium oxide (Ca10Cr7O28). Calcium-chromium oxide is made up of what are known as Kagomé lattices — reminiscent of the pattern of triangles and hexagons woven in Japanese basketry. As a result, a complex set of isotropic magnetic interactions develop in this material, consisting of not only anti-ferromagnetic interactions but also much stronger ferromagnetic interactions that according to conventional understanding should prevent the existence of spin liquid behavior. Magnetic and Neutron scattering experiments conducted in Germany, France, England, and the USA, as well as muon spectroscopy experiments performed in Switzerland have however shown that the spins in these samples retain their collective motion even at temperatures as low as 20 millikelvin and behave like a quantum spin liquid.

Quantum Advantage on Information Leakage for Equality

Abstract: We prove a lower bound on the information leakage of any classical protocol.

Computing the equality function in the simultaneous message passing (SMP) model. Our bound is valid in the finite length regime and is strong enough to demonstrate a quantum advantage in terms of information leakage for practical quantum protocols. We prove our bound by obtaining an improved finite size version of the communication bound due to Babai and Kimmel, relating randomized.

Communication to deterministic communication in the SMP model. We then relate. information leakage to randomized communication through a series of reductions.

We first provide alternative characterizations for information leakage, allowing us to link it to average length communication while allowing for. shared randomness (pairwise, with the referee). A Markov inequality links this.

With bounded length communication, and a Newman type argument allows us to go from shared to private randomness. The only reduction in which we incur more.

ComNav releases Quantum algorithm for its OEM boards

BTW — make sure you view that reference whitepaper on the new quantum algorithms on OEM boards.

ComNav Technologies has released its new generation Quantum algorithm to international market. The Quantum algorithm can be easily achieved through a firmware upgrade (version 2.5.2 and above), and suits all ComNav OEM boards and OEM-based receivers.

An upgrade to ComNav’s Quan algorithm, the Quantum algorithm dramatically improves the stability and reliability of RTK positioning in complex environments, as well as providing a DP-filter enhancement for the ComNav GNSS products.