Quantum Photon Properties Revealed in Plasmon
For years, researchers have been interested in developing quantum computers — the theoretical next generation of technology that will outperform conventional computers. Instead of holding data in bits, the digital units used by computers today, quantum computers store information in units called “qubits.” One approach for computing with qubits relies on the creation of two single photons that interfere with one another in a device called a waveguide. Results from a recent applied science study at Caltech support the idea that waveguides coupled with another quantum particle — the surface plasmon — could also become an important piece of the quantum computing puzzle.
Read more: http://www.laboratoryequipment.com/news/2014/04/quantum-photon-properties-revealed-plasmon
Quasi-Particles Move Between Graphene Layers
Belgian scientists have used a particle physics theory to describe the behavior of particle-like entities, referred to as excitons, in two layers of graphene, a one-carbon-atom-thick honeycomb crystal. In a paper published in Springer’s EPJ B, Michael Sarrazin from the Univ. of Namur, and Fabrice Petit from the Belgian Ceramic Research Centre in Mons, studied the behavior of excitons in a bilayer of graphene through an analogy with excitons evolving in two abstract parallel worlds, described with equations typically used in high-energy particle physics.
The authors used the equations reflecting a theoretical world consisting of a bi-dimensional space sheet — a so-called brane — embedded in a space with three dimensions. Specifically, the authors described the quantum behavior of excitons in a universe made of two such brane worlds. They then made an analogy with a bilayer of graphene sheets, in which quantum particles live in a separate space-time.
Read more: http://www.laboratoryequipment.com/news/2014/02/quasi-particles-move-between-graphene-layers
Tiny Components a Step Toward Quantum Computer
Scientists and engineers from an international collaboration led by Mark Thompson from the Univ. of Bristol have, for the first time, generated and manipulated single particles of light on a silicon chip – a major step forward in the race to build a quantum computer.
Quantum computers and quantum technologies in general are widely anticipated as the next major technology advancement, and are poised to replace conventional information and computing devices in applications ranging from ultra-secure communications and high-precision sensing to immensely powerful computers. Quantum computers themselves will likely lead to breakthroughs in the design of new materials and in the discovery of new medical drugs.
Read more: http://www.laboratoryequipment.com/news/2014/01/tiny-components-step-toward-quantum-computer
In a recent study, published in Science, researchers have been able to observe, for the first time, the collective spin dynamics of ultra-cold fermions with large spins.
Understanding collective behavior of ultra-cold quantum gases is of great interest since it is intimately related to many encountered systems in nature such as human behavior, swarms of birds, traffic jam, sand dunes, neutron stars, fundamental magnetic properties of solids or even super-fluidity or super-conductivity. In all of these everyday life examples, collective behavior plays a crucial role since all participating objects move — voluntarily or not — synchronously.
Read more: http://www.laboratoryequipment.com/news/2014/01/researchers-see-macro-behaviors-ultra-cold-quantum-gases
Physicists at the Univ. of Basel have been successful in generating photons — the quantum particles of light — with only one color. This is useful for quantum information science. The scientists have actively stabilized the wavelength of the photons emitted by a semiconductor thereby neutralizing the charge noise in the semiconductor. The results were developed in close collaboration with the Universities of Bochum, Paderborn and Lyon and have been published in the magazine Physical Review X.
Light consists of quantum particles, so-called photons. With a single photon it is possible to transfer quantum information. The information can be encoded in the polarization or in the phase of the photons’ wave packets and can be used in quantum communication and computation. In such applications, a single-photon source, a device that emits photons one by one, is a prerequisite. One of the most promising platforms for single-photon sources is based on semiconductor quantum dots. One major unsolved problem is, however, that the “color” (or wavelength) of the photons emitted by a quantum dot is not locked to a precise value, rather, it wanders around randomly.
Read more: http://www.laboratoryequipment.com/news/2013/11/scientists-are-developing-stable-quantum-light-source
Researchers Make Most Powerful Terahertz Quantum Cascade Laser
Whether it is diagnostic imaging, analysis of unknown substances or ultrafast communication – terahertz radiation sources are becoming more and more important. At the Vienna Univ. of Technology, an important breakthrough has been achieved.
Terahertz waves are invisible, but incredibly useful; they can penetrate many materials which are opaque to visible light and they are perfect for detecting a variety of molecules. Terahertz radiation can be produced using tiny quantum cascade lasers, only a few millimeters wide. This special kind of lasers consists of tailor made semiconductor layers on a nanometer scale. At TU Vienna a new world record has now been set; using a special merging technique, two symmetrical laser structures have been joined together, resulting in a quadruple intensity of laser light.
Read more: http://www.laboratoryequipment.com/news/2013/10/researchers-make-most-powerful-terahertz-quantum-cascade-laser
Nanostructures Could Offer Way to Control Quantum Effect… Once a Mystery Is Solved
You might think that a pair of parallel plates hanging motionless in a vacuum just a fraction of a micrometer away from each other would be like strangers passing in the night — so close but destined never to meet. Thanks to quantum mechanics, you would be wrong.
Scientists working to engineer nanoscale machines know this only too well as they have to grapple with quantum forces and all the weirdness that comes with them. These quantum forces, most notably the Casimir effect, can play havoc if you need to keep closely spaced surfaces from coming together.
Read more: http://www.laboratoryequipment.com/news/2013/10/nanostructures-could-offer-way-control-quantum-effect-once-mystery-solved
Physicist Solves ‘Schrödinger’s Cat’ Debate
Univ. of Arkansas physicist Art Hobson has offered a solution, within the framework of standard quantum physics, to the long-running debate about the nature of quantum measurement.
In an article published by Physical Review A, a journal of the American Physical Society, Hobson argues that the phenomenon known as “nonlocality” is key to understanding the measurement problem illustrated by “Schrödinger’s cat.”
Read more: http://www.laboratoryequipment.com/news/2013/08/physicist-solves-schr%C3%B6dingers-cat-debate
An alternative and novel concept in electronics utilizes the wave quantum number of the electron in a crystalline material to encode information. In a new article in Nature Materials, researchers propose using this valley degree of freedom in diamond to enable valleytronic information processing or as a new route to quantum computing.
In electronic circuits, bits of information (1:s and 0:s) are encoded by the presence or absence of electric charge. For fast information processing, e.g. in computer processors or memories, charges have to be moved around at high switching rates. Moving charges requires energy, which inevitably causes heating and gives rise to a fundamental limit to the switching rate. As an alternative it is possible to utilize other properties than the charge of electrons to encode information and thereby avoid this fundamental limit. An example of this is “spintronics” where the spin of the electron is used to carry information.
Read more: http://www.laboratoryequipment.com/news/2013/07/concept-aids-development-%E2%80%98valleytronics%E2%80%99-diamonds
New Technology Will Test 50-Year-Old Physics Theory
Physicists working at the National Institute of Standards and Technology (NIST) and the Joint Quantum Institute (JQI) are edging ever closer to getting really random.
Their work — a photon source that provides the most efficient delivery of a particularly useful sort of paired photons yet reported — sounds prosaic enough, but it represents a new high-water mark in a long-term effort toward two very different and important goals, a definitive test of a key feature of quantum theory and improved security for Internet transactions.
Read more: http://www.laboratoryequipment.com/news/2013/06/new-technology-will-test-50-year-old-physics-theory
Researchers Achieve Quantum Network Milestone
Using clouds of ultra-cold atoms and a pair of lasers operating at optical wavelengths, researchers have reached a quantum network milestone: entangling light with an optical atomic coherence composed of interacting atoms in two different states. The development could help pave the way for functional, multi-node quantum networks.
The research, done at the Georgia Institute of Technology, used a new type of optical trap that simultaneously confined both ground-state and highly-excited (Rydberg) atoms of the element rubidium. The large size of the Rydberg atoms – which have a radius of about one micron instead of a usual sub-nanometer size – gives them exaggerated electromagnetic properties and allows them to interact strongly with one another.
Read more: http://www.laboratoryequipment.com/news/2013/06/researchers-achieve-quantum-network-milestone
Researchers Make First Observation of Spin Hall Effect in a Quantum Gas
Researchers at the National Institute of Standards and Technology (NIST) have reported the first observation of the “spin Hall effect” in a Bose-Einstein condensate (BEC), a cloud of ultracold atoms acting as a single quantum object. As one consequence, they made the atoms, which spin like a child’s top, skew to one side or the other, by an amount dependent on the spin direction. Besides offering new insight into the quantum mechanical world, they say the phenomenon is a step toward applications in “atomtronics” — the use of ultracold atoms as circuit components.
Read more: http://www.laboratoryequipment.com/news/2013/06/researchers-make-first-observation-spin-hall-effect-quantum-gas
Fine-Tuning Quantum Dots Key to Better Color Displays
Tiny particles of matter called quantum dots, which emit light with exceptionally pure and bright colors, have found a prominent role as biological markers. In addition, they are realizing their potential in computer and television screens, and have promise in solid-state lighting. New research at MIT could now make these quantum dots even more efficient at delivering precisely tuned colors of light.
These materials, called colloidal semiconductor quantum dot nanocrystals, can emit any color of light, depending on their exact size or composition. But there is some variability in the spread of colors that different batches of nanocrystals produce, and until now there has been no way to tell whether that variability came from within individual particles or from variations among the nanocrystals in a batch.
Read more: http://www.laboratoryequipment.com/news/2013/06/fine-tuning-quantum-dots-key-better-color-displays
Quantum Encryption May Be Hackable
Quantum communication systems offer the promise of virtually unbreakable encryption. Unlike classical encryption, which is used to send secure data over networks today and whose security depends on the difficulty of solving mathematical problems like the factoring of large numbers, most quantum encryption schemes keep the encryption key separate from the data. This approach ensures that an eavesdropper with access only to the data could not decipher the key. However, researchers have recently demonstrated that even quantum encryption may be susceptible to hacking.
Read more: http://www.laboratoryequipment.com/news/2013/05/quantum-encryption-may-be-hackable
One of the many promising applications of quantum mechanics in the information sciences is quantum key distribution (QKD), in which the counterintuitive behavior of quantum particles guarantees that no one can eavesdrop on a private exchange of data without detection.
As its name implies, QKD is intended for the distribution of cryptographic keys that can be used for ordinary, nonquantum cryptography. That’s because it requires the transmission of a huge number of bits for each one that’s successfully received. That kind of inefficiency is tolerable for key distribution, but not for general-purpose communication.
Read more: http://www.laboratoryequipment.com/news/2013/05/research-makes-quantum-encryption-practical