Scientists at Penn Engineering have developed a quantum sensing method that detects signals from individual atoms.
Category: quantum physics – Page 224
Mathematical methods point to possibility of particles long thought impossible
From the early days of quantum mechanics, scientists have thought that all particles can be categorized into one of two groups—bosons or fermions—based on their behavior.
However, new research by Rice University physicist Kaden Hazzard and former Rice graduate student Zhiyuan Wang shows the possibility of particles that are neither bosons nor fermions. Their study, published in Nature, mathematically demonstrates the potential existence of paraparticles that have long been thought impossible.
“We determined that new types of particles we never knew of before are possible,” said Hazzard, associate professor of physics and astronomy.
Discovery of new class of particles could take quantum mechanics one step further
Amid the many mysteries of quantum physics, subatomic particles don’t always follow the rules of the physical world. They can exist in two places at once, pass through solid barriers and even communicate across vast distances instantaneously. These behaviors may seem impossible, but in the quantum realm, scientists are exploring an array of properties once thought impossible.
In a new study, physicists at Brown University have now observed a novel class of quantum particles called fractional excitons, which behave in unexpected ways and could significantly expand scientists’ understanding of the quantum realm.
“Our findings point toward an entirely new class of quantum particles that carry no overall charge but follow unique quantum statistics,” said Jia Li, an associate professor of physics at Brown.
Physicists achieve simulation of non-Hermitian skin effect in 2D with ultracold fermions
A research team led by The Hong Kong University of Science and Technology (HKUST) has achieved a groundbreaking quantum simulation of the non-Hermitian skin effect in two dimensions using ultracold fermions, marking a significant advance in quantum physics research.
Quantum mechanics, which typically considers a well-isolated system from its environment, describes ubiquitous phenomena ranging from electron behavior in solids to information processing in quantum devices. This description typically requires a real-valued observable—specifically, a Hermitian model (Hamiltonian).
The hermiticity of the model, which guarantees conserved energy with real eigenvalues, breaks down when a quantum system exchanges particles and energy with its environment. Such an open quantum system can be effectively described by a non-Hermitian Hamiltonian, providing crucial insights into quantum information processing, curved space, non-trivial topological phases, and even black holes. Nevertheless, many questions about non-Hermitian quantum dynamics remain unanswered, especially in higher dimensions.
Proximity effect enables non-ferroelectric materials to gain new properties
Ferroelectrics are special materials with polarized positive and negative charges—like a magnet has north and south poles—that can be reversed when external electricity is applied. The materials will remain in these reversed states until more power is applied, making them useful for data storage and wireless communication applications.
Now, turning a non-ferroelectric material into one may be possible simply by stacking it with another ferroelectric material, according to a team led by scientists from Penn State who demonstrated the phenomenon, called proximity ferroelectricity.
The discovery offers a new way to make ferroelectric materials without modifying their chemical formulation, which commonly degrades several useful properties. This has implications for next-generation processors, optoelectronics and quantum computing, the scientists said. The researchers published their findings in the journal Nature.
Superconducting nanostrip single photon detectors fabricated of aluminum thin-films
We systematically investigated the detection performance of Al nanostrips for single photons at various wavelengths. The Al films were deposited using magnetron sputtering, and the sophisticated nanostructures and morphology of the deposited films were revealed through high-resolution transmission electron microscopy. The fabricated Al meander nanostrips, with a thickness of 4.2 nm and a width of 178 nm, exhibited a superconducting transition temperature of 2.4 K and a critical current of approximately 5 μA at 0.85 K. While the Al nanostrips demonstrated a saturated internal quantum efficiency for 405-nm photons, the internal detection efficiency exhibited an exponential dependence on bias current without any saturation tendency for 1550-nm photons. This behavior can be attributed to the relatively large diffusion coefficient and coherence length of the Al films.
Scientists unite Einstein’s relativity and quantum mechanics through Schrödinger’s cat equation
The intricate relationship between quantum mechanics and classical physics has long puzzled scientists. Quantum mechanics operates in a bizarre world where particles can exist in multiple states simultaneously, a concept known as superposition. However, this principle appears to break down in the macroscopic realm.
Planets, stars, and even the universe itself don’t exhibit such superpositions, creating a significant challenge in understanding how the universe transitions from quantum to classical behavior.
At the heart of this enigma is the question: how does the universe, if fundamentally quantum, adhere to classical laws like general relativity? This puzzle has led to groundbreaking work by researchers such as Matteo Carlesso and his colleagues at the University of Trieste.
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Beyond fermions and bosons: unveiling new particle behaviors in mechanics.
In the world, particles traditionally fall into two categories: fermions (like electrons) and bosons (like photons), each obeying distinct exchange rules. These “exchange statistics” shape the behaviors of particles, from the structure of atoms to the glow of lasers. In two dimensions, a peculiar third type, called anyons, has been theorized and observed, adding a twist to this framework. But could there be even more possibilities?
This study ventures into uncharted territory by revisiting “parastatistics,” an idea from theory that goes beyond fermions and bosons. Previously dismissed as merely theoretical and equivalent to the known particle types, parastatistics now emerges in a new light. The researchers reveal that particles obeying non-trivial parastatistics can exist in real physical systems and behave in fundamentally different ways. These “paraparticles” follow unique rules of exclusion, resulting in strange and exotic thermodynamic behaviors unlike any seen in fermions or bosons.
To bring this concept to life, the team developed a mathematical framework for paraparticles, showing how they naturally fit within the broader universe. They designed solvable models where paraparticles arise as quasiparticles—tiny, particle-like excitations in materials—observable through their distinct exchange behavior. Remarkably, these models work in both one and two dimensions, demonstrating the tangible potential of paraparticles in real-world systems.
The findings hint at exciting possibilities: a new class of quasiparticles in condensed matter physics and, perhaps more provocatively, the existence of elementary particles governed by entirely novel statistics. This discovery could expand our understanding of the world and open the door to unimagined phenomena in both theory and experiment.
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