A new approach manufactures many high-quality diamond-based quantum memory chips simultaneously on a single wafer.
Category: quantum physics
Is Spacetime Fundamental, or is it Emergent? With Brian Cox
In this conversation, Neil deGrasse Tyson and co-host Chuck Nice are joined by physicist Brian Cox to explore one of the deepest open questions in modern physics: whether space and time are fundamental—or emergent.
The discussion spans emergent spacetime, quantum entanglement, black holes, wormholes, and the black hole information paradox, including ideas like ER = EPR, causality protection, and whether information is ever truly destroyed. The core idea centers on the possibility that spacetime itself emerges from deeper quantum information structures, challenging our intuitive understanding of reality.
From ‘Are We The Universe’s Way of Knowing Itself? With Brian Cox’: • Are We The Universe’s Way of Knowing Itsel…
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Corralling Interfering Anyons
Link.aps.org/doi/10.1103/Physics.19.
A delicate interference experiment elucidates the collective behavior of quasiparticles that are neither bosons nor fermions, but something in between.
When you live in theory-land, as I do, anyons in fractional quantum Hall (FQH) systems are an emblem of elegance. They address a fundamental question in quantum mechanics—the classification of indistinguishable particles—by breaking the long-rooted dichotomy between fermions and bosons and replacing it with a continuum of possibilities. Their implications are far reaching. Anyons account for the “hierarchy” of FQH states and they inspire visions of topologically protected quantum computation [1]. In experiment-land, the most direct manifestation of anyons is the phase that the system’s wave function acquires when two anyons are interchanged or when one winds around another. This phase is at the heart of a new experiment performed by Noah Samuelson and Andrea Young of the University of California, Santa Barbara, and their collaborators [2].
Electric current stabilizes spins at unstable points for new types of computing
A research team has discovered a new way to control tiny magnetic properties inside materials using electric current, which could possibly pave the way for new types of computing technologies. The work is based on spintronics, a field that uses not only the electric charge of electrons but also their “spin,” a quantum property that can be thought of as a tiny magnet.
Spintronics is already used in magnetic random access memory (MRAM), a type of memory that keeps data even when the power is turned off. This is different from conventional memory, which loses information without electricity.
In MRAM, data is stored depending on whether spins point “up” or “down.” These two stable states are separated by an energy barrier, which helps keep the data secure. However, this stability also makes it harder to switch between states, requiring strong electric currents.
First quantum oscillations observed in gallium nitride holes
Gallium nitride, a semiconductor that can operate at high voltages, temperatures, and frequencies, has enabled technologies from LED lighting to high-power electronics. Now Cornell researchers have observed a quantum property of the material for the first time, an advance that could expand its technological reach.
Much of gallium nitride’s value as a semiconductor lies in how quickly negatively charged electrons move through the material. But the material could become even more useful if scientists better understood its positively charged “holes,” which behave like mobile pockets of missing electrons but have been difficult to study.
Understanding how to control the flow of the holes—as engineers have achieved in silicon semiconductors—would allow gallium nitride to reach its full potential.
Physicists find electronic agents that govern flat band quantum materials
Physicists have directly visualized the fundamental electronic building blocks of flat-band quantum materials, a class of systems in which electron motion is effectively quenched and strong interactions give rise to emergent phases of matter. In a study published in Nature Physics, Qimiao Si’s group at Rice University, in collaboration with researchers at the Weizmann Institute of Science, identified compact molecular orbitals that act as the key electronic agents governing the exotic behavior of these materials.
“In flat band materials, electron motion experiences destructive interference,” said Si, the Harry C. and Olga K. Wiess Professor of Physics and Astronomy and director of Rice’s Extreme Quantum Materials Alliance.
These flat band materials are also topological with properties that are preserved as the material continuously bends or stretches in any symmetry-preserving way.
New controls can stretch, blur and even reverse quantum time flow
In new research published in Physical Review X, scientists have designed quantum control protocols that generate processes more consistent with time flowing backward than forward. The protocols—techniques to control quantum systems—modify a quantum system’s “arrow of time,” the concept of time as moving in one forward direction. The work opens up possibilities for energy extraction from quantum systems and for quantum state preparation.
A quantum system, such as a collection of qubits, is governed by the laws of quantum mechanics. The team’s control protocols can prevent the emergence of the arrow of time in a quantum system or even invert its direction—that is, cause quantum time to appear to flow in reverse.
As an application of their research, the team leveraged their control protocols to design a measurement engine that extracts energy from quantum measurements performed on the system.
Superconducting quantum processor performs well with significantly less wiring
Quantum computers, computing systems that process information using quantum mechanical effects, could outperform classical computers on some computational tasks. These computers rely on qubits, the basic units of quantum information, which can exist in multiple states (0, 1 or both simultaneously), due to quantum effects known as superposition and entanglement.
Many of the quantum computers developed in recent years are based on conventional superconductors, materials that exhibit an electrical resistance of zero at extremely low temperatures. To operate reliably and exhibit superconductivity, circuits based on these materials need to be cooled down to millikelvin temperatures.
In quantum computers, each qubit typically requires its own control line. This means that engineers need to introduce several wires that carry electrical pulses (i.e., signal lines), and the number of necessary wires increases with the number of qubits. As quantum computers grow larger, this can be problematic, as processors become harder to build and reliably operate.