Entanglement is a widely studied quantum physics phenomenon, in which two particles become linked in such a way that the state of one affects the state of another, irrespective of the distance between them. When studying systems comprised of several strongly interacting particles (i.e., many body systems) in two or more dimensions, numerically predicting the amount of information shared between these particles, a measure known as entanglement entropy (EE), becomes highly challenging.
More than two decades ago, scientists predicted that at ultra-low temperatures, many atoms could undergo ‘quantum superchemistry’ and chemically react as one. They’ve finally shown it’s real.
As transistors are made ever tinier to fit more computing power into a smaller footprint, they bump up against a big problem: quantum mechanics. Electrons get jumpy in small devices and leak out, which wastes energy while degrading performance. Now a team of researchers is showing that it doesn’t have to be that way. With careful engineering, it’s possible to turn electrons’ quantum behavior into an advantage.
A team of English, Canadian, and Italian researchers have developed a single-molecule transistor that harnesses quantum effects. At low temperatures, the single-molecule device shows a strong change in current with only a small change in gate voltage, nearing a physical limit known as the sub-threshhold swing. Getting near or beyond this limit will allow transistors to be switched with lower voltages, making them more efficient and generating less waste heat. The research team, including physicists at Queen Mary University of London, achieved this by taking advantage of how quantum interference alters the flow of current in single molecules.
“We’ve demonstrated, in principle, that you can use destructive quantum interference for something useful.” —Jan Mol, Queen Mary University of London.
Iron screws and other so-called ferromagnetic materials are made up of atoms with electrons that act like little magnets. Normally, the orientations of the magnets are aligned within one region of the material but are not aligned from one region to the next. Think of packs of tourists in Times Square pointing to different billboards all around them. But when a magnetic field is applied, the orientations of the magnets, or spins, in the different regions line up and the material becomes fully magnetized. This would be like the packs of tourists all turning to point at the same sign.
A new study by Hebrew University has made a significant breakthrough by successfully incorporating single-photon sources into small chips that operate at room temperature. This development marks a crucial progress in the field of quantum photonics, opening up possibilities for its use in quantum computing and cryptography. It represents a key achievement in creating usable quantum photonic devices, signaling an optimistic outlook for the complete realization of quantum technologies, including computing, communication, and sensing.
A recent study, spearheaded by Boaz Lubotzky during his Ph.D. research, along with Prof. Ronen Rapaport from the Racah Institute of Physics at The Hebrew University of Jerusalem, in collaboration with teams from Los Alamos National Laboratory (LANL) in the USA and from Ulm University in Germany, unveiled a significant advancement toward the on-chip integration of single-photon sources at room temperature. This achievement represents a significant step forward in the field of quantum photonics and holds promise for various applications including quantum computing, cryptography, and sensing.
Future quantum computers could be based on electrons floating above liquid helium, according to study by a RIKEN physicist and collaborators, appearing in Physical Review Applied.
IBM has created a quantum error-correcting code about 10 times more efficient than prior methods.
A team of scientists from Columbia, Nanjing University, Princeton, and the University of Munster, writing in the journal Nature, have presented the first experimental evidence of collective excitations with spin called chiral graviton modes (CGMs) in a semiconducting material.
To understand the relationship between the science fiction genre and the Many-Worlds Interpretation, let’s turn to two men – a scientist and a writer. The scientist is Hugh Everett III (1930−1982), a physicist who developed the notion of parallel universes based on an original interpretation of quantum mechanics. He proposed that a pre-formulated theory should be the basis of scientific measurement, quite the opposite of the traditional scientific process in which measurement preceded and determined the theory. But quantum particles do not behave normally, so quantum phenomena and their atomic dynamics cannot be measured by the Newtonian mechanics traditionally applied to the universe.
When Hugh Everett published “Relative State Formulation of Quantum Mechanics” in the Reviews of Modern Physics scientific journal (Volume 29, Issue 3, July — September 1957), his theory that there are many worlds existing in parallel at the same space and time as our own sounded like fantasy fiction to a skeptical scientific world.
While scientists scoffed for more than a decade after Everett published his theory, someone else entered the scene. His name was Philip K. Dick, a scruffy beatnik writer who tramped around Berkeley (California) looking for ways to describe this alternative reality – the one hiding behind our visible reality.
Quantum computers will break encryption one day. But converting data into light particles and beaming them around using thousands of satellites might be one way around this problem.
