Explore recent breakthroughs in quantum teleportation, the science of secure communication, and quantum computing.
Category: quantum physics – Page 86
String theory aims to explain all fundamental forces and particles in the universe—essentially, how the world operates on the smallest scales. Though it has not yet been experimentally verified, work in string theory has already led to significant advancements in mathematics and theoretical physics.
Dr. Ksenia Fedosova, a researcher at the Mathematics Münster Cluster of Excellence at the University of Münster has, along with two co-authors, added a new piece to this puzzle: They have proven a conjecture related to so-called 4-graviton scattering, which physicists have proposed for certain equations. The results have been published in the Proceedings of the National Academy of Sciences.
Gravitons are hypothetical particles responsible for gravity. “The 4-graviton scattering can be thought of as two gravitons moving freely through space until they interact in a ‘black box’ and then emerge as two gravitons,” explains Fedosova, providing the physical background for her work. “The goal is to determine the probability of what happens in this black box.”
An exploration of the bizarre mystery of John Wheeler’s quantum foam, virtual particles and virtual black holes and how the universe could have come from a quantum fluctuation.
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A research team led by Professor Jaedong Lee from the Department of Chemical Physics of DGIST has introduced a novel quantum state and a pioneering mechanism for extracting and controlling quantum information using exciton and Floquet states.
Collaborating with Professor Noejung Park from UNIST’s Department of Physics, the team has, for the first time, demonstrated the formation and synthesis process of exciton and Floquet states, which arise from light-matter interactions in two-dimensional semiconductors.
The study, published in Nano Letters in October, captures quantum information in real-time as it unfolds through entanglement, offering valuable insights into the exciton formation process in these materials, thereby advancing quantum information technology.
A recent study in Physical Review Letters explores quantum effects on black hole thermodynamics and geometry, focusing on extending two classical inequalities into the quantum regime.
Black holes have been thoroughly studied through a classical approach based on Einstein’s general theory of relativity. However, this approach does not account for quantum effects like Hawking radiation.
The goal of the study was for the researchers to refine classical theories by including quantum effects, thereby offering an improved understanding of black hole dynamics.
MIT physicists have taken a key step toward solving the puzzle of what leads electrons to split into fractions of themselves. Their solution sheds light on the conditions that give rise to exotic electronic states in graphene and other two-dimensional systems.
The new work is an effort to make sense of a discovery that was reported earlier this year by a different group of physicists at MIT, led by Assistant Professor Long Ju. Ju’s team found that electrons appear to exhibit “fractional charge” in pentalayer graphene — a configuration of five graphene layers that are stacked atop a similarly structured sheet of boron nitride.
Ju discovered that when he sent an electric current through the pentalayer structure, the electrons seemed to pass through as fractions of their total charge, even in the absence of a magnetic field. Scientists had already shown that electrons can split into fractions under a very strong magnetic field, in what is known as the fractional quantum Hall effect. Ju’s work was the first to find that this effect was possible in graphene without a magnetic field — which until recently was not expected to exhibit such an effect.
“Quantum physicists are realizing that they can’t ignore the fact that the reference frame Alice is anchored to … might have multiple possible locations at once.”
The quantum nature of reference frames can even affect the perceived order of events.
In a paper this year, the physicist Časlav…
The reference frames from which observers view quantum events can themselves have multiple possible locations at once — an insight with potentially major ramifications.
Quantum Computing and state-sponsored Cyber Warfare: How quantum will transform Nation-State Cyber Attacks
Posted in cybercrime/malcode, encryption, information science, mathematics, military, quantum physics | Leave a Comment on Quantum Computing and state-sponsored Cyber Warfare: How quantum will transform Nation-State Cyber Attacks
The rise of quantum computing is more than a technological advancement; it marks a profound shift in the world of cybersecurity, especially when considering the actions of state-sponsored cyber actors. Quantum technology has the power to upend the very foundations of digital security, promising to dismantle current encryption standards, enhance offensive capabilities, and recalibrate the balance of cyber power globally. As leading nations like China, Russia, and others intensify their investments in quantum research, the potential repercussions for cybersecurity and international relations are becoming alarmingly clear.
Imagine a world where encrypted communications, long thought to be secure, could be broken in mere seconds. Today, encryption standards such as RSA or ECC rely on complex mathematical problems that would take traditional computers thousands of years to solve. Quantum computing, however, changes this equation. Using quantum algorithms like Shor’s, a sufficiently powerful quantum computer could factorize these massive numbers, effectively rendering these encryption methods obsolete.
This capability could give state actors the ability to decrypt communications, access sensitive governmental data, and breach secure systems in real time, transforming cyber espionage. Instead of months spent infiltrating networks and monitoring data flow, quantum computing could provide immediate access to critical information, bypassing traditional defenses entirely.
Strong interactions between subatomic particles like electrons occur when they are at a specific energy level known as the van Hove singularity. These interactions give rise to unusual properties in quantum materials, such as superconductivity at high temperatures, potentially ushering in exciting technologies of tomorrow.
Research suggests topological materials that allow electrons to flow only on their surface to be promising quantum materials. However, the quantum properties of these materials remain relatively unexplored.
A study co-led by Nanyang Asst Prof Chang Guoqing of NTU’s School of Physical and Mathematical Sciences identified two types of van Hove singularities in the topological materials rhodium monosilicide (RhSi) and cobalt monosilicide (CoSi).
Achieving the full potential of quantum computing will require the development of quantum gates—circuits that carry out fundamental operations—with much higher fidelity than is currently available. An average gate fidelity surpassing 99.9%, for example, would enable not only efficient fault-tolerant quantum computing with error correction but also effective mitigation of errors in current noisy intermediate-scale quantum devices. In this work, we report on a two-qubit gate that achieves that milestone and sustains it for 12 h.
Superconducting qubits, with their ease of scalability and controllability, are prime candidates for building quantum processors. One type known as a transmon is renowned for its high coherence and ease of manufacturing and is thus already widely embraced in academia and industry. In general, single-qubit gates need negligible coupling between two transmon qubits, whereas two-qubit gates require a large coupling. This necessitates a coupling mechanism that can be tuned to both nearly zero and a very large value.
Various coupling schemes based on transmons have been shown to address this issue. Our work focuses on an innovative coupler known as the double-transmon coupler (DTC), which has been only theoretically proposed. We report the first experimental realization of the DTC, achieving gate fidelities of 99.9% for two-qubit gates and 99.98% for single-qubit gates, demonstrated by using two transmons coupled by the DTC.