Not all scientific claims are equal. How can you tell if a discovery is real?
Extremely massive fundamental particles could exist, but they would seriously mess with our understanding of quantum mechanics.
Handedness—and the related concept of chirality—are double-sided ways of understanding how matter breaks symmetries.
Extreme quantum states.
A new mathematical framework helps physicists define the degree of quantumness of a system.
Shantanu Chakrabartty’s laboratory has been working to create sensors that can run on the least amount of energy. His lab has been so successful at building smaller and more efficient sensors, that they’ve run into a roadblock in the form of a fundamental law of physics.
Sometimes, however, when you hit what appears to be an impenetrable roadblock, you just have to turn to quantum physics and tunnel through it. That’s what Chakrabartty and other researchers at the McKelvey School of Engineering at Washington University in St. Louis did.
The development of these self-powered quantum sensors from the lab of Chakrabartty, the Clifford W. Murphy Professor in the Preston M. Green Department of Systems & Electrical Engineering, was published online Oct. 28 in the journal Nature Communications.
A technology for building quantum computers that has long been sidelined by major companies is gaining momentum. As quantum computing has transformed from academic exercise to big business over the past decade, the spotlight has mostly been on one approach — the tiny superconducting loops embraced by technology giants such as IBM and Intel. Superconductors enabled Google last year to claim it had achieved ‘quantum advantage’ with a quantum machine that for the first time performed a particular calculation that is beyond the practical capabilities of the best classical computer. But a separate approach, using ions trapped in electric fields, is gaining traction in the quest to make a commercial quantum computer.
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Now that researchers have created time crystals, the next step is to understand more about this bizarre material.
Researchers devise groundbreaking new methods to create and duplicate single-atom transistors for quantum computers.
Harun Šiljak, Trinity College Dublin
Google reported a remarkable breakthrough towards the end of 2019. The company claimed to have achieved something called quantum supremacy, using a new type of “quantum” computer to perform a benchmark test in 200 seconds. This was in stark contrast to the 10,000 years that would supposedly have been needed by a state-of-the-art conventional supercomputer to complete the same test.
Despite IBM’s claim that its supercomputer, with a little optimisation, could solve the task in a matter of days, Google’s announcement made it clear that we are entering a new era of incredible computational power.
Quantum computing is a new paradigm in computing that utilizes the benefits of quantum mechanics to enhance the computing experience. Quantum computers will no longer rely on binary digits (0 and 1 states), that computers have relied on since the early beginnings, but will instead use quantum bits, which can be in a superposition of states. Quantum bits, or qubits, have the advantage of being in many states at once, offering parallel computing advantages. For example, they have long been regarded as far superior to classical computers for applications in data encryption.
Although the concept of quantum computers has been known for several decades, practical realizations are still lacking. The main limiting factor has been the critical influence of the environment on a qubit. Most physical systems need to be in perfectly controlled conditions in order to remain in the superposition state, whereas any interaction (mechanical, thermal, or other) with the environment perturbs this state and ruins the qubit. Such perturbation is termed “decoherence” that has plagued many potential qubit systems.
Graphene, having spurred research into numerous novel directions, is naturally also considered as a candidate material host for qubits. For example, back in 2013, a team of researchers from MIT found that graphene can be made into a topological insulator – meaning that electrons with one spin direction move around the graphene edges clockwise, whereas those that have the opposite spin move counterclockwise. They made this happen by applying two magnetic fields: one perpendicular to the graphene sheet, to make the electrons flow at sheet edges only, and another parallel to the sheet, that separates the two spin contributions. Electron spin has long been considered a candidate qubit, because it is inherently a quantum system that is in a superposition of states. In graphene, the spins move along the sheet edges robustly, without much decoherence. Furthermore, the same research showed switching the spin selection on and off, an important feature of q-bit transistors.
Researchers led by City College of New York physicist Pouyan Ghaemi report the development of a quantum algorithm with the potential to study a class of many-electron quantums system using quantum computers. Their paper, entitled “Creating and Manipulating a Laughlin-Type ν=1/3 Fractional Quantum Hall State on a Quantum Computer with Linear Depth Circuits,” appears in the December issue of PRX Quantum, a journal of the American Physical Society.
“Quantum physics is the fundamental theory of nature which leads to formation of molecules and the resulting matter around us,” said Ghaemi, assistant professor in CCNY’s Division of Science. “It is already known that when we have a macroscopic number of quantum particles, such as electrons in the metal, which interact with each other, novel phenomena such as superconductivity emerge.”
However, until now, according to Ghaemi, tools to study systems with large numbers of interacting quantum particles and their novel properties have been extremely limited.
