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Category: quantum physics – Page 896

Faster and better method around Q-dots development which ultimately extends the quality of Quantum Dots plus mass production of Q-Dots is much faster through this new method. Hoping this causes the costs of new cameras, phone displays, monitors/ video displays are now able to be created more cheaply and in larger quantities.

Materials researchers at North Carolina State University have fine-tuned a technique that enables them to apply precisely controlled silica coatings to quantum dot nanorods in a day — up to 21 times faster than previous methods. In addition to saving time, the advance means the quantum dots are less likely to degrade, preserving their advantageous optical properties.

Quantum dots are nanoscale semiconductor materials whose small size cause them to have electron energy levels that differ from larger-scale versions of the same material. By controlling the size of the quantum dots, researchers can control the relevant energy levels — and those energy levels give quantum dots novel optical properties. These characteristics make quantum dots promising for applications such as opto-electronics and display technologies.

But quantum dots are surrounded by ligands, which are organic molecules that are sensitive to heat. If the ligands are damaged, the optical properties of the quantum dots suffer.

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Finding evidence of many-body localization in a closed quantum system.

During equilibration ordinary many-body systems lose all information about the initial state. Every morning we experience an example for this behaviour. Milk poured into a cup of coffee mixes perfectly and after some time it is impossible to say how exactly the two fluids were put together. The same behaviour holds for almost all quantum systems. However, recently a new phenomenon called “many-body localization” has been predicted theoretically, which allows well insulated quantum systems to preserve memory of the initial state forever. Now a team of scientists around Dr. Christian Groß and Professor Immanuel Bloch (Director at MPQ and Chair of Quantum Optics at LMU Munich), in cooperation with David Huse (Princeton University), has obtained evidence of such a behaviour in a two-dimensional quantum system of cold rubidium atoms trapped in an optical lattice.

The scientists observed that – beyond a certain degree of disorder imprinted on the particle ensemble in the beginning – the system would relax into a steady state still containing detailed microscopic information about its past. “We were able to observe the transition from a thermalized state into a many-body localized phase”, Christian Groß points out. “It is the first observation of that kind in a regime that is not accessible with state-of-the-art simulations on classical computers.” The experiment is not only of fundamental interest; the results might also lead to new ways for storing quantum information.

Motivated by the foundational problem of how interacting particles behave in a disordered system, in the 1950s the American physicist Philip Warren Anderson discovered the famous localization phenomenon for non-interacting particles, now called “Anderson localization”. Here, disorder prevents the particles to move and consequently all transport is stopped. But what happens when disorder comes together with interactions? Will interactions lead to transport and thermalization, or will the localization persist even at high energies? So far, there is no theoretical model that faithfully predicts the evolution of a closed quantum system in more than one dimension under these conditions, although, the possibility for localization has been theoretically suggested.

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When the bang became a bounce.

How the universe began is one of the most brain-breaking questions you could possibly ask, and the Big Bang is probably the answer most people accept. But what if the infinitely dense point from which the entire universe burst forth wasn’t the beginning of everything, but merely the middle of an ongoing cycle? That’s the theory of the Big Bounce, which suggests that the universe regularly cycles through periods of expansion and contraction, meaning the Big Bang may have been preceded by an earlier universe collapsing in on itself. A new study details how this might be possible.

The idea of the Big Bounce has been bouncing around since 1922, but explaining just how the universe transitions between expanding and contracting has always been an issue. What’s to stop a universe just contracting into a point and collapsing completely? According to researchers from Imperial College London and the Perimeter Institute for Theoretical Physics in Canada, it may be the same quantum mechanics that prevent atoms from deteriorating into nothing.

In our universe as it currently is, there’s an asymmetry between the laws of the subatomic world and those that govern larger matter. Large-scale physics and quantum mechanics exist side-by-side now, but that doesn’t mean it’s always been the case: back when the universe was young and everything in it was tiny, quantum mechanics may have been the only set of laws in effect, an idea known as conformal symmetry. So the same processes that keep electrons from losing energy as they orbit the nucleus and destroying the atom may have prevented the universe from collapsing into oblivion.

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More steps forward for QC through the discovery of a versatile effective spin system suitable for quantum simulations and universal quantum computation.

Using trapped atomic ions, we demonstrate a tailored and versatile effective spin system suitable for quantum simulations and universal quantum computation. By simply applying microwave pulses, selected spins can be decoupled from the remaining system and, thus, can serve as a quantum memory, while simultaneously, other coupled spins perform conditional quantum dynamics. Also, microwave pulses can change the sign of spin-spin couplings, as well as their effective strength, even during the course of a quantum algorithm. Taking advantage of the simultaneous long-range coupling between three spins, a coherent quantum Fourier transform—an essential building block for many quantum algorithms—is efficiently realized. This approach, which is based on microwave-driven trapped ions and is complementary to laser-based methods, opens a new route to overcoming technical and physical challenges in the quest for a quantum simulator and a quantum computer.

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Listen up all my QC buddies; the air force wants to hear from you. You have QC ideas for fighter jets they want you.

Guess I need to submit them some of mine.

The Air Force wants white papers that describe new ways quantum computing could help achieve its mission, according to an amended Broad Agency Announcement posted Friday. Eventually, the government could provide a test-bed where a contractor might install, develop and test a quantum computing system, according to the announcement.

Last year, the Air Force announced it had about $40 million available to fund research into, and the eventual maintenance and installation of a quantum system — a branch of emerging computing technology that relies on the mechanics of atomic particles to process complex equations.

The Air Force Research Laboratory’s Information Directorate, which focuses on processes such as signal processing, networking technology, cyber research and supercomputing, is collecting those white papers.

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Another article on QC where the author is not well connected or knowledgeable about the details on QC’s advancement on entanglement. I suggest the author to learn about the use of Synthetic Diamonds in controlling and managing entanglement plus we now have a way to detect & trace high-dimensional entanglement that I shared 20 days ago. I suggest if authors wish to write on QC please make sure that you have the latest information so that your better informed.

The computers of today have just about hit their limits, and scientists around the world are scrambling to build the first viable quantum computer — a machine that could increase processing speeds 100-million-fold.

The biggest challenge in scaling up a quantum computer is figuring out how to entangle enough quantum bits (qubits) to perform calculations, but a team of engineers in the US say they might finally have a solution.

Quantum computers are set to revolutionise how we process data in the future, because they’re not limited to the 1s and 0s of binary code that today’s computers rely on. That binary code is holding us back, because if you can only use a combination of 1s and 0s, there’s a finite amount of data that can be processed, no matter how fast you go.

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Aalto University scientists have broken the world record by fourteen fold in the energy resolution of thermal photodetection.

The record was made using a partially superconducting microwave detector. The discovery may lead to ultrasensitive cameras and accessories for the emerging quantum computer.

Artistic image of a hybrid superconductor-metal microwave detector

Figure 1: Artistic image of a hybrid superconductor-metal microwave detector. (Image: Ella Maru Sudio)

The first of the two key enabling developments is the new detector design consisting of tiny pieces of superconducting aluminum and a golden nanowire. This design guarantees both efficient absorption of incoming photons and very sensitive readout. The whole detector is smaller than a single human blood cell.

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