Tag: Index
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Unitarity
Introduction Unitarity, a principle central to quantum mechanics and quantum field theory, is the mathematical expression of the fundamental conservation law in these theories – the conservation of probability. At the most basic level, it guarantees that the total probability of all possible outcomes of a quantum mechanical system is always one. The Basics: Unitary…
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Z-Pinch
Introduction Z-Pinch, also known as zeta pinch, is a type of plasma confinement system that uses an electric current in the plasma to generate a magnetic field that compresses it. This physical principle is applied in various scientific fields, notably in fusion power and astrophysics research. Basic Principle: Lorentz Force The core principle of the…
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Optoelectronics
Introduction Optoelectronics, a sub-field of photonics, blends the fascinating realms of optics and electronics. It concerns devices that operate on the interaction of light and electrical signals. The Heart of Optoelectronics: The Photon The quintessential particle of light, the photon, is the main player in optoelectronics. Understanding how photons interact with materials forms the foundation…
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Van Hove Singularity
Introduction The concept of the Van Hove Singularity, introduced by Belgian physicist Léon Van Hove, adds an interesting dimension to the study of solids in condensed matter physics. This intriguing concept is linked to the density of states in a solid material, and it has significant implications for electronic properties. Understanding the Density of States…
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Overhauser Effect
Introduction The Overhauser Effect, named after American physicist Albert Overhauser, is a fascinating phenomenon in nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy. It demonstrates a unique quantum mechanical interaction between the magnetic moments of electrons and nuclei. Basic Concept of Overhauser Effect In simple terms, the Overhauser Effect refers to the polarization…
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Vibronic Spectroscopy
Introduction Vibronic spectroscopy provides a window into the fascinating realm of molecular vibrations and electronic transitions. This scientific tool reveals the hidden dance of molecules, helping us unravel the mysteries of molecular structures and their dynamic behaviors. Understanding Vibronic Spectroscopy The term “vibronic” is a portmanteau of “vibrational” and “electronic.” As the name suggests, vibronic…
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Luminiferous Aether
Introduction The concept of the luminiferous aether (also known as “ether”) was central to the theoretical framework of physics before the advent of Einstein’s theory of relativity. Essentially, it was considered the medium through which light waves propagate, much like sound waves require a medium such as air to travel. The Nature of Light: A…
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Kelvin Waves
Introduction Kelvin waves are a type of wave in fluids that are confined to the boundary of the fluid, such as a coastline or the equator of the Earth’s atmosphere or oceans. They are named after the physicist William Thomson, 1st Baron Kelvin, who first described these waves in 1879. The Basics of Waves In…
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Kramers Degeneracy
Introduction Kramers degeneracy is a cornerstone theorem in quantum mechanics, which states that the energy levels of a half-integer spin system are at least doubly degenerate in the presence of time-reversal symmetry. The theorem is named after the Dutch physicist Hendrik Kramers, who first postulated it in 1930. Basics of Quantum Degeneracy In quantum mechanics,…
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Johnson-Nyquist Noise
Introduction Johnson-Nyquist Noise, also known as thermal noise or Johnson noise, is the electronic noise generated by the thermal agitation of the charge carriers (usually the electrons) inside an electrical conductor at equilibrium. It’s an essential consideration in electronics and signal processing and was first measured accurately by John B. Johnson and then theoretically analyzed…