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Category: quantum physics – Page 512

Researchers demonstrate secure information transfer using spatial correlations in quantum entangled beams of light

Researchers at the University of Oklahoma led a study recently published in Science Advances that proves the principle of using spatial correlations in quantum entangled beams of light to encode information and enable its secure transmission.

Light can be used to encode information for high-data rate transmission, long-distance communication and more. But for secure communication, encoding large amounts of information in light has additional challenges to ensure the privacy and integrity of the data being transferred.

Alberto Marino, the Ted S. Webb Presidential Professor in the Homer L. Dodge College of Arts, led the research with OU doctoral student and the study’s first author Gaurav Nirala and co-authors Siva T. Pradyumna and Ashok Kumar. Marino also holds positions with OU’s Center for Quantum Research and Technology and with the Quantum Science Center, Oak Ridge National Laboratory.

Sony announces venture into quantum computing via UK firm Quantum Motion

The Japanese electronics giant Sony has announced its first steps into quantum computing by joining other investment groups in a £42m venture in the UK quantum computing firm Quantum Motion. The move by the investment arm of Sony aims to boost the company’s expertise in silicon quantum chip development as well as to assist in a potential quantum computer roll-out onto the Japanese market.

Quantum Motion was founded in 2017 by scientists from University College London and the University of Oxford. It already raised a total of £20m via “seed investment” in 2017 and a “series A” investment in 2020. Quantum Motion uses qubits based on standard silicon chip technology and can therefore exploit the same manufacturing processes that mass-produces chips such as those found in smartphones.

A full-scale quantum computer, when built, is likely to require a million logical qubits to perform quantum-based calculations, with each logical qubit needing thousands of physical qubits to allow for robust error checking. Such demands will, however, require a huge amount of associated hardware if they are to be achieved. Quantum Motion claims that its technology could tackle this problem because it develops scalable arrays of qubits based on CMOS silicon technology to achieve high-density qubits.

Why has there been no progress in physics since 1973?

The twentieth century was a truly exciting time in physics.

From 1905 to 1973, we made extraordinary progress probing the mysteries of the universe: special relativity, general relativity, quantum mechanics, the structure of the atom, the structure of the nucleus, enumerating the elementary particles.

Then, in 1973, this extraordinary progress… stopped.

I mean, where are the fundamental discoveries in the last 50 years equal to general relativity or quantum mechanics?

Why has there been no progress in physics since 1973?

For this high-budget, big-hair episode of The Last Theory, I flew all the way to Oxford to tell you why progress stopped, and why it’s set to start again: why progress in physics might be about to accelerate in the early twenty-first century in a way we haven’t seen since those heady days of the early twentieth century.

Continue reading “Why has there been no progress in physics since 1973?” | >

Quantum computers are better at guessing, new study demonstrates

Daniel Lidar, the Viterbi Professor of Engineering at USC and Director of the USC Center for Quantum Information Science & Technology, and Dr. Bibek Pokharel, a Research Scientist at IBM Quantum, have achieved a quantum speedup advantage in the context of a “bitstring guessing game.” They managed strings up to 26 bits long, significantly larger than previously possible, by effectively suppressing errors typically seen at this scale. (A bit is a binary number that is either zero or one). Their paper is published in the journal Physical Review Letters.

Quantum computers promise to solve certain problems with an advantage that increases as the problems increase in complexity. However, they are also highly prone to errors, or noise. The challenge, says Lidar, is “to obtain an advantage in the real world where today’s quantum computers are still ‘noisy.’” This noise-prone condition of current is termed the “NISQ” (Noisy Intermediate-Scale Quantum) era, a term adapted from the RISC architecture used to describe classical computing devices. Thus, any present demonstration of quantum speed advantage necessitates noise reduction.

The more unknown variables a problem has, the harder it usually is for a to solve. Scholars can evaluate a computer’s performance by playing a type of game with it to see how quickly an algorithm can guess hidden information. For instance, imagine a version of the TV game Jeopardy, where contestants take turns guessing a secret word of known length, one whole word at a time. The host reveals only one correct letter for each guessed word before changing the secret word randomly.

Everything Will Evaporate

Even space and time if it’s quantum.

What will be the ultimate fate of our universe? There are a number of theories and possibilities, but at present the most likely scenario seems to be that the universe will continue to expand, most mass will eventually find its way into a black hole, and those black holes will slowly evaporate into Hawking Radiation, resulting in what is called the “heat death” of the universe. Don’t worry, this will likely take 1.7×10106 years, so we got some time.

But what about objects, like stellar remnants, that are not black holes? Will the ultimate fate of the universe still contain some neutron stars and cold white dwarfs that managed to never get sucked up by a black hole? To answer this question we have to back up a bit and talk about Hawking Radiation.

Stephen Hawking famously proposed this idea in 1975 – he was asked if black holes have a temperature, and that sent him down another type of hole until Hawking Radiation popped out as the answer. But what is Hawking Radiation? The conventional answer is that the vacuum of space isn’t really nothing, it still contains the quantum fields that make up spacetime. Those quantum field do not have to have zero energy, and so occasionally virtual particles will pop into existence, always in pairs with opposite properties (like opposite charge and spin), and then they join back together, cancelling each other out. But at the event horizon of black holes, the distance at which light can just barely escape the black hole’s gravity, a virtual pair might occur where one particle gets sucked into the black hole and the other escapes. The escaping particle is Hawking Radiation. It carries away a little mass from the black hole, causing it to glow slightly and evaporate very slowly.

The ‘breath’ between atoms—a new building block for quantum technology

University of Washington researchers have discovered they can detect atomic “breathing,” or the mechanical vibration between two layers of atoms, by observing the type of light those atoms emitted when stimulated by a laser. The sound of this atomic “breath” could help researchers encode and transmit quantum information.

The researchers also developed a device that could serve as a new type of building block for quantum technologies, which are widely anticipated to have many future applications in fields such as computing, communications and sensor development.

The researchers published these findings June 1 in Nature Nanotechnology.

Understanding the tantalizing benefits of tantalum for improved quantum processors

Whether it’s baking a cake, building a house, or developing a quantum device, the quality of the end product significantly depends on its ingredients or base materials. Researchers working to improve the performance of superconducting qubits, the foundation of quantum computers, have been experimenting using different base materials in an effort to increase the coherent lifetimes of qubits.

The coherence time is a measure of how long a retains quantum information, and thus a primary measure of performance. Recently, scientists discovered that using tantalum in makes them perform better, but no one has been able to determine why—until now.

Scientists from the Center for Functional Nanomaterials (CFN), the National Synchrotron Light Source II (NSLS-II), the Co-design Center for Quantum Advantage (C2QA), and Princeton University investigated the fundamental reasons that these qubits perform better by decoding the chemical profile of tantalum.

Quantum Physics Could Explain Nearly All the Mysteries of How Life Works

Quantum effects are phenomena that occur between atoms and molecules that can’t be explained by classical physics. It has been known for more than a century that the rules of classical mechanics, like Newton’s laws of motion, break down at atomic scales. Instead, tiny objects behave according to a different set of laws known as quantum mechanics.

For humans, who can only perceive the macroscopic world, or what’s visible to the naked eye, quantum mechanics can seem counterintuitive and somewhat magical. Things you might not expect happen in the quantum world, like electrons “tunneling” through tiny energy barriers and appearing on the other side unscathed or being in two different places at the same time in a phenomenon called superposition.

I am trained as a quantum engineer. Research in quantum mechanics is usually geared toward technology. However, and somewhat surprisingly, there is increasing evidence that nature – an engineer with billions of years of practice — has learned how to use quantum mechanics to function optimally. If this is indeed true, it means that our understanding of biology is radically incomplete. It also means that we could possibly control physiological processes by using the quantum properties of biological matter.

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