Tag: Quantum
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Intensity
Introduction to Intensity In physics, intensity is a measure of the energy flux, or the power per unit area. It is commonly used to describe various phenomena such as light, sound, and electric fields. It quantifies how much energy passes through a specific area in a given time period. Mathematical Definition of Intensity In the…
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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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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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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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Kibble-Zurek Mechanism (KZM)
Introduction The Kibble-Zurek Mechanism (KZM) is a theoretical framework in the field of non-equilibrium physics that aims to explain the emergence of topological defects during phase transitions. Proposed by Tom Kibble and Wojciech Zurek, the KZM explains how the universe behaves when transitioning from a high symmetry phase to a low symmetry phase, a phenomenon…
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Vacuum Fluctuations
Introduction Quantum mechanics introduces an intriguing concept: vacuum fluctuations. This principle suggests that even in a perfect vacuum, there are tiny, momentary changes in energy. Unlike classical physics, which describes a vacuum as an absolute emptiness, quantum physics sees it as a sea of transient particles and antiparticles that continuously form and annihilate. Vacuum State…
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Hamiltonian (Quantum Mechanics)
Introduction Quantum mechanics, with its blend of abstract concepts and mathematical formalism, has been the cornerstone of our understanding of the microscopic world. The Hamiltonian, named after physicist Sir William Rowan Hamilton, plays a central role in this theory, acting as the generator of time evolution in quantum systems. The Hamiltonian in Classical and Quantum…
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Ionization Energy
Introduction Ionization energy is a fundamental property of atoms and molecules in the field of atomic and molecular physics. It refers to the minimum energy required to remove an electron from an atom or a molecular entity in its gaseous state. It’s usually measured in electron volts (eV) or joules (J). First Ionization Energy The…
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Klein-Nishina Formula
Introduction The Klein-Nishina formula is an essential result in quantum electrodynamics that describes the angular distribution of photons scattered off a single, free electron. Named after Oskar Klein and Yoshio Nishina, who derived the formula in 1928, it takes into account the relativistic and quantum mechanical effects of the scattering process, particularly in the case…
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Liouville’s Theorem
Introduction Liouville’s Theorem is a crucial principle in both statistical and Hamiltonian mechanics. Named after the French mathematician Joseph Liouville, the theorem asserts that the phase space volume occupied by a closed system remains constant throughout its evolution. Phase space, a key concept in physics, is an abstract space where all possible states of a…