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Archive for the ‘quantum physics’ category: Page 132

Oct 5, 2023

Quantum repeaters use defects in diamond to interconnect quantum systems

Posted by in categories: computing, engineering, particle physics, quantum physics

Ben Dixon, a researcher in the Optical and Quantum Communications Technology Group, explains how the process works: “First, you need to generate pairs of specific entangled qubits (called Bell states) and transmit them in different directions across the network link to two separate quantum repeaters, which capture and store these qubits. One of the quantum repeaters then does a two-qubit measurement between the transmitted and stored qubit and an arbitrary qubit that we want to send across the link in order to interconnect the remote quantum systems. The measurement results are communicated to the quantum repeater at the other end of the link; the repeater uses these results to turn the stored Bell state qubit into the arbitrary qubit. Lastly, the repeater can send the arbitrary qubit into the quantum system, thereby linking the two remote quantum systems.”

To retain the entangled states, the quantum repeater needs a way to store them — in essence, a memory. In 2020, collaborators at Harvard University demonstrated holding a qubit in a single silicon atom (trapped between two empty spaces left behind by removing two carbon atoms) in diamond. This silicon “vacancy” center in diamond is an attractive quantum memory option. Like other individual electrons, the outermost (valence) electron on the silicon atom can point either up or down, similar to a bar magnet with north and south poles. The direction that the electron points is known as its spin, and the two possible spin states, spin up or spin down, are akin to the ones and zeros used by computers to represent, process, and store information. Moreover, silicon’s valence electron can be manipulated with visible light to transfer and store a photonic qubit in the electron spin state. The Harvard researchers did exactly this; they patterned an optical waveguide (a structure that guides light in a desired direction) surrounded by a nanophotonic optical cavity to have a photon strongly interact with the silicon atom and impart its quantum state onto that atom. Collaborators at MIT then showed this basic functionality could work with multiple waveguides; they patterned eight waveguides and successfully generated silicon vacancies inside them all.

Lincoln Laboratory has since been applying quantum engineering to create a quantum memory module equipped with additional capabilities to operate as a quantum repeater. This engineering effort includes on-site custom diamond growth (with the Quantum Information and Integrated Nanosystems Group); the development of a scalable silicon-nanophotonics interposer (a chip that merges photonic and electronic functionalities) to control the silicon-vacancy qubit; and integration and packaging of the components into a system that can be cooled to the cryogenic temperatures needed for long-term memory storage. The current system has two memory modules, each capable of holding eight optical qubits.

Oct 5, 2023

Advanced Quantum Material Curves the Fabric of Space

Posted by in categories: energy, quantum physics

The latest research on quantum materials and electron curves could revamp our energy-efficient electronics.

Oct 5, 2023

Start of the Fully Fault Tolerant Age of Quantum Computers

Posted by in categories: computing, information science, quantum physics

Without full fault tolerance in quantum computers we will never practically get past 100 qubits but full fault tolerance will eventually open up the possibility of billions of qubits and beyond. In a Wright Brothers Kittyhawk moment for Quantum Computing, a fully fault-tolerant algorithm was executed on real qubits. They were only three qubits but this was never done on real qubits before.

This is the start of the fully fault tolerant age of quantum computers. For quantum computers to be the real deal of unlimited computing disruption then we needed full fault tolerance on real qubits.

Oct 5, 2023

No-heat quantum engine makes its debut

Posted by in categories: particle physics, quantum physics

Researchers demonstrate a prototype engine powered by the quantum statistics of bosons and fermions.

Oct 5, 2023

Creation of quantum dots wins 2023 chemistry Nobel

Posted by in categories: biotech/medical, chemistry, quantum physics

The award honors three scientists who discovered and built quantum dots, which are now used in everything from TVs to medical tools.

Oct 5, 2023

Breaking the Born-Oppenheimer Approximation — Experiments Unveil Long-Theorized Quantum Phenomenon

Posted by in categories: quantum physics, solar power, sustainability

Nearly a century ago, physicists Max Born and J. Robert Oppenheimer developed a hypothesis about the functioning of quantum mechanics within molecules. These molecules consist of complex systems of nuclei and electrons. The Born-Oppenheimer approximation postulates that the movements of nuclei and electrons within a molecule occur independently and can treated separately.

This model works the vast majority of the time, but scientists are testing its limits. Recently, a team of scientists demonstrated the breakdown of this assumption on very fast time scales, revealing a close relationship between the dynamics of nuclei and electrons. The discovery could influence the design of molecules useful for solar energy conversion, energy production, quantum information science, and more.

The team, including scientists from the U.S. Department of Energy’s (DOE) Argonne National Laboratory, Northwestern University, North Carolina State University, and the University of Washington, recently published their discovery in two related papers in Nature and Angewandte Chemie International Edition.

Oct 4, 2023

The Nobel Prize in Chemistry 2023

Posted by in categories: biotech/medical, chemistry, quantum physics

Moungi G. Bawendi, Louis E. Brus and Alexei I. Ekimov are awarded the Nobel Prize in Chemistry 2023 for the discovery and development of quantum dots. These tiny particles have unique properties and now spread their light from television screens and LED lamps. They catalyse chemical reactions and their clear light can illuminate tumour tissue for a surgeon.

“Toto, I’ve a feeling we’re not in Kansas anymore,” is a classic quote from the film The Wizard of Oz. Twelve-year-old Dorothy faints onto her bed when her house is swept away by a powerful tornado, but when the house lands again and she steps outside the door, her dog Toto in her arms, everything has changed. Suddenly she is in a magical, technicolour world.

If an enchanted tornado were to sweep into our lives and shrink everything to nano dimensions, we would almost certainly be as astonished as Dorothy in the land of Oz. Our surroundings would be dazzlingly colourful and everything would change. Our gold earrings would suddenly glimmer in blue, while the gold ring on our finger would shine a ruby red. If we tried to fry something on the gas hob, the frying pan might melt. And our white walls – whose paint contains titanium dioxide – would start generating lots of reactive oxygen species.

Oct 4, 2023

Nobel prize in physics awarded for work unveiling the secrets of electrons

Posted by in categories: particle physics, quantum physics

The 2023 Nobel prize in physics has been awarded to a trio of scientists for pioneering tools used to study the world of electrons.

Electrons are sub-atomic particles that play a role in many phenomena we see every day, from electricity to magnetism. This year’s three Nobel physics laureates demonstrated a way to create extremely short pulses of light in order to investigate processes that involve electrons.

Pierre Agostini from The Ohio State University in the US, Ferenc Krausz from the Max Planck Institute of Quantum Optics in Germany and Anne L’Huillier from Lund University in Sweden will share the prize sum of 11 million Swedish kronor (£822,910).

Oct 4, 2023

Entangled Light from Multitasking Atoms Could Spark Quantum Breakthroughs

Posted by in categories: encryption, quantum physics

This surreal scenario is what would actually happen if the traffic light was a single atom illuminated by a laser beam, as recently shown experimentally by researchers in Berlin. They looked at the light scattered by an atom and saw that photons—the tiniest particles of light—arrived at the detector one at a time. The scientists blocked the brightest color they saw, and suddenly pairs of photons of two slightly different colors started arriving at their detector simultaneously. They reported their findings in Nature Photonics in July.

The reason for this counterintuitive effect is that single atoms are skilled little multitaskers. Through different underlying processes, they can scatter a variety of colors at the same time like a dangerous traffic light that shines all three colors at once. Yet because of quantum interference between these processes, an observer only sees one of the metaphorical traffic light’s colors at a time, preserving peace on the road.

This experiment also paves the way for novel quantum information applications. When the brightest color is blocked, the photons that pop up simultaneously are entangled with each other, behaving in sync even when they are separated over large distances. This provides a new tool for quantum communication and information processing in which entangled photon pairs can serve as distributed keys in quantum cryptography or store information in a quantum memory device.

Oct 4, 2023

Quantum computing enters the fluxonium era: Breakthrough sends supercomputer accuracy to next level

Posted by in categories: mobile phones, quantum physics, supercomputing

CAMBRIDGE, Mass. — Researchers at MIT have achieved a significant breakthrough in quantum computing, bringing the potential of these incredible thinking machines closer to realization. Quantum computers promise to handle calculations far too complex for current supercomputers, but many hurdles remain. A primary challenge is addressing computational errors faster than they arise.

In a nutshell, quantum computers find better and quicker ways to solve problems. Scientists believe quantum technology could solve extremely complex problems in seconds, while traditional supercomputers you see today could need months or even years to crack certain codes.

What makes these next generation supercomputers different from your everyday smartphone and laptop is how they process data. Quantum computers harness the properties of quantum physics to store data and perform their functions. While traditional computers use “bits” (either a 1 or a 0) to encode information on your devices, quantum technology uses “qubits.”