Tag: Quantum
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Interferometry
Introduction Interferometry is a family of techniques in physics which use the phenomenon of interference to make precise measurements of various quantities. It involves superposing (or “mixing”) waves to extract information about the waves or the media they have interacted with. Basic Principle The basic principle of interferometry involves splitting a wave into two or…
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Interference
Introduction Interference is a fundamental concept in wave theory, describing the phenomenon where two or more waves combine to form a resultant wave. The principle of interference is central to many areas of physics, including optics, acoustics, and quantum mechanics. Constructive and Destructive Interference When two waves meet, they interfere with each other. The superposition…
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Dirac Equation
Introduction The Dirac equation is a relativistic wave equation derived by British physicist Paul Dirac in 1928. It provides a description of elementary spin-1/2 particles, such as electrons, consistent with both quantum mechanics and the theory of special relativity. The Equation The Dirac equation in natural units () is written as: where is the wave…
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Davisson-Germer Experiment
Introduction The Davisson-Germer experiment, conducted by Clinton Davisson and Lester Germer in 1927, confirmed the wave nature of electrons. The experiment provided key evidence supporting the de Broglie hypothesis, which proposed that particles can exhibit both particle-like and wave-like properties. The Experiment Davisson and Germer aimed an electron beam at a crystalline nickel target and…
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Casimir Effect
Introduction The Casimir Effect is a quantum mechanical phenomenon where two uncharged metallic plates attract each other when placed a few nanometers apart in a vacuum. It was first predicted by Dutch physicist Hendrik Casimir in 1948. Theory The Casimir effect arises due to the quantum fluctuations of the electromagnetic field in a vacuum. Even…
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Bell’s Theorem
Introduction Bell’s theorem, proposed by physicist John Bell in 1964, is a pivotal result in quantum mechanics. It deals with the concept of local realism, a principle stating that physical processes occurring at one location do not depend on the properties of objects at other locations. Statement of Bell’s Theorem Bell’s theorem states that: “No…
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Stern-Gerlach Experiment
Introduction The Stern-Gerlach experiment, conducted by Otto Stern and Walther Gerlach in 1922, is a fundamental experiment in quantum mechanics. It demonstrated the quantization of angular momentum and provided early evidence for the existence of spin, a quantum property of particles. Principle of the Experiment The experiment involves passing a beam of particles (in the…
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Scattering Theory
Introduction Scattering theory is a framework in physics that is used to study and understand the interactions of particles and fields. It is especially important in quantum mechanics, quantum field theory, and particle physics, as well as in classical wave phenomena like light scattering. Basic Principle Scattering involves an incident wave or particle that is…
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Spectroscopy
Introduction Spectroscopy is a scientific method used to investigate and measure the interaction of various types of electromagnetic radiation with matter. The spectrum obtained provides a lot of information about the physical and chemical properties of the substance under investigation. Types of Spectroscopy There are various types of spectroscopy, classified based on the nature of…
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Superconductivity
Introduction Superconductivity is a quantum mechanical phenomenon where certain materials can conduct electric current with zero electrical resistance. This state occurs below a certain temperature, known as the critical temperature (). BCS Theory The underlying theory of superconductivity is the BCS theory (Bardeen–Cooper–Schrieffer theory). This theory explains superconductivity as a state in which electrons with…