The double-exchange mechanism is a concept in solid-state physics and materials science that explains the behavior of electrons in certain types of materials, particularly in relation to ferromagnetism and electron transport. It describes how the movement of one type of electron can be coupled with the spin state of another electron, leading to unique magnetic and electrical properties.
The Grimm–Sommerfeld rule is a principle used in quantum mechanics that helps to estimate the transition rates between quantum states, particularly in the context of atomic and molecular transitions. It provides a way to understand the selection rules governing the allowed or forbidden transitions between different energy levels of a quantum system. The rule was formulated by the physicists Wilhelm Grimm and Arnold Sommerfeld, and it applies primarily to electric dipole transitions.
The term "local structure" can have different meanings depending on the context in which it is used. Here are a few common interpretations: 1. **Mathematics/Geometry**: In this context, local structure refers to the properties or behavior of a space or object in a small neighborhood around a point.
MINDO, which stands for MInimal N-on-Diagonal Order, is a theoretical model used in computational chemistry, specifically for estimating molecular energies and properties. It is part of the larger family of semi-empirical quantum chemistry methods, which simplify the computational process by approximating certain integrals and parameters based on experimental data or simpler calculations.
Shungite is a black, lustrous mineral primarily composed of carbon, with other elements such as silica, alumina, and various minerals. It is believed to originate from a unique geological formation in and around the area of Shunga village in Russia, where significant deposits are found. Shungite is notable for its high carbon content, which can range from 30% to over 98%, depending on the specific type of shungite.
Optical pumping is a process used in physics and engineering to manipulate the energy states of atoms or molecules using light. It involves the absorption of photons, usually from a laser or other light source, to excite electrons in an atom from a lower energy state to a higher energy state. This process can selectively populate certain energy levels, leading to a non-equilibrium distribution of atomic or molecular states.
Photon antibunching is a quantum optical phenomenon that occurs when photons emitted from a source are detected in such a way that they exhibit a reduced probability of being detected in pairs (or bunches) compared to what would be expected from classical light sources. This effect is a key signature of non-classical light and is often observed in light emitted by single quantum emitters, such as single atoms, quantum dots, or single molecules.
A quasiprobability distribution is a mathematical construct used primarily in quantum mechanics and quantum information theory. It extends the concept of classical probability distributions to accommodate the peculiar behaviors of quantum systems, which can exhibit phenomena such as superposition and entanglement. In classical probability, distributions must adhere to certain constraints, such as non-negativity and normalization, where all probabilities sum to one.
"Argiles d'lignite du Soissonnais" refers to a specific type of clay found in the Soissonnais region of France, which is notable for its lignite deposits. Lignite, also known as brown coal, is a type of coal that is intermediate in carbon content and energy output between peat and higher-grade coals.
Charentese amber, also known as "amber from Charente," refers to a specific type of amber that is found in the Charente region of southwestern France. This amber is known for its unique geological and historical characteristics, having formed from the resin of ancient coniferous trees millions of years ago. The Charente region's amber deposits are typically dated to the Cretaceous period, around 100 million years ago.
An inertia damper is a device used to reduce vibrations or oscillations in mechanical systems. It functions by utilizing the principles of inertia to absorb or dissipate energy that can cause unwanted motion, such as in buildings, automotive systems, or machinery. ### Key Features of Inertia Dampers: 1. **Inertial Mass**: The damper typically includes a mass that resists motion. When the system experiences vibrations, the mass moves in a way that counteracts these vibrations.
Orbital-free density functional theory (OF-DFT) is a computational approach within the framework of density functional theory (DFT) that aims to describe the electronic structure of systems without explicitly considering the electronic wavefunctions (orbitals). Traditional DFT typically relies on the Kohn-Sham equations, which involve solving for the single-particle orbitals of electrons in a potential determined by electronic density.
Slater integrals are important quantities in the fields of atomic and solid-state physics, particularly in the context of multi-electron atomic systems and solid-state materials. They are used to describe the effects of electron-electron interactions in systems with multiple electrons, such as atoms and molecules. In quantum mechanics, the interaction between electrons is governed by their Coulomb repulsion.
Vacuum level refers to the measure of pressure in a vacuum system relative to atmospheric pressure. It indicates how much lower the pressure is compared to the surrounding atmospheric pressure. Vacuum levels are typically expressed in units of pressure such as pascals (Pa), torr, millimeters of mercury (mmHg), or inches of mercury (inHg). In practical terms, vacuum levels can be categorized into different ranges: 1. **Low Vacuum**: Approximately 0.
"Southland Tales" is a 2006 science fiction film written and directed by Richard Kelly, who is also known for his earlier film "Donnie Darko." The movie is set in a dystopian version of Los Angeles in the near future, specifically in the year 2008, and it explores themes of war, government surveillance, and the nature of reality through its complex narrative.
The "particle in a box" is a foundational concept in quantum mechanics that serves to illustrate key principles of quantum theory. It describes a simple model where a particle, such as an electron, is confined to a one-dimensional region of space, typically a box or a well with infinitely high potential walls. This model helps to understand how quantum systems behave under the influence of confinement.