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Wheeler's Delayed Choice Experiment
Wheeler's delayed-choice experiment describes a family of thought experiments in quantum physics proposed by John Archibald Wheeler, with the most prominent among them appearing in 1978 and 1984. These experiments illustrate the central point of quantum theory: "It is wrong to attribute a tangibility to the photon in all its travel from the point of entry to its last instant of flight." These experiments close a loophole in the traditional double-slit experiment demonstration that quantum behavior depends on the experimental arrangement. The experiment closes the loophole that a photon might adjust its behavior from particle to wave behavior or vice versa. By altering the apparatus after the photon is supposed to be in "flight", the loophole is closed. Cosmic versions of the delayed-choice experiment use photons emitted billions of years ago; the results are unchanged. The concept of delayed choice has been productive of many revealing experiments. New versions of the delayed c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Thought Experiment
A thought experiment is an imaginary scenario that is meant to elucidate or test an argument or theory. It is often an experiment that would be hard, impossible, or unethical to actually perform. It can also be an abstract hypothetical that is meant to test our intuitions about morality or other fundamental philosophical questions. History The ancient Greek , "was the most ancient pattern of mathematical proof", and existed before Euclidean geometry, Euclidean mathematics, where the emphasis was on the conceptual, rather than on the experimental part of a thought experiment. Johann Witt-Hansen established that Hans Christian Ørsted was the first to use the equivalent German term . Ørsted was also the first to use the equivalent term in 1820. By 1883, Ernst Mach used in a different sense, to denote exclusively the conduct of a experiment that would be subsequently performed as a by his students. Physical and mental experimentation could then be contrasted: Mach asked hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Double-slit Experiment
In modern physics, the double-slit experiment demonstrates that light and matter can exhibit behavior of both classical particles and classical waves. This type of experiment was first performed by Thomas Young in 1801, as a demonstration of the wave behavior of visible light. In 1927, Davisson and Germer and, independently, George Paget Thomson and his research student Alexander Reid demonstrated that electrons show the same behavior, which was later extended to atoms and molecules. Thomas Young's experiment with light was part of classical physics long before the development of quantum mechanics and the concept of wave–particle duality. He believed it demonstrated that the Christiaan Huygens' wave theory of light was correct, and his experiment is sometimes referred to as Young's experiment or Young's slits. The experiment belongs to a general class of "double path" experiments, in which a wave is split into two separate waves (the wave is typically made of many photons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
SETI
Seti or SETI may refer to: Astrobiology * SETI, the search for extraterrestrial intelligence. ** SETI Institute, an astronomical research organization *** SETIcon, a former convention organized by the SETI Institute ** Berkeley SETI Research Center, an astronomical research organization *** SETI@home, a distributed computing project ** Active SETI, the attempt to send messages to intelligent aliens Egyptology * Seti (commander), grandfather of Seti I * Seti (Viceroy of Kush) * Seti I (died 1279 BC), pharaoh * Seti II (died 1197 BC), pharaoh * Seti-Merenptah, a son of Seti II * Seti, son of Amun-her-khepeshef * Sethi, one of List of children of Ramesses II#, the sons of Ramesses II Music * SETI (band), an ambient music band from New York City * SETI (The Kovenant album), ''SETI'' (The Kovenant album), an album by metal band The Kovenant Places * Seti River, a tributary of the Karnali River in Nepal * Seti Gandaki River or Seti River, a tributary of the Trishuli River in Nepal * S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Wheeler Astro Lab
Wheeler may refer to: Places United States * Wheeler, Alabama, an unincorporated community * Wheeler, Arkansas, an unincorporated community * Wheeler, California, an unincorporated community * Wheeler, Illinois, a village * Wheeler, Indiana, a census-designated place * Wheeler, Mississippi, an unincorporated community * Wheeler, Nebraska, a ghost town * Wheeler, New York, a town * Wheeler, Oregon (other) * Wheeler, Texas, a city * Wheeler, Virginia, an unincorporated community * Wheeler, Washington, a census-designated place * Wheeler, West Virginia, an unincorporated community * Wheeler, Wisconsin, a village * Wheeler County (other) * Wheeler Crest or Ridge, a ridge in Mono and Inyo Counties, California * Wheeler Dam, Alabama ** Wheeler Lake, the lake created by the dam * Wheeler Geologic Area, a protected area of Mineral County, Colorado * Wheeler Island, Connecticut * Wheeler Islands (West Virginia) * Wheeler National Wildlife Refuge, near Decatur, Alabama * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Glan–Thompson Prism
A Glan–Thompson prism is a type of polarizing prism similar to the Nicol prism and Glan–Foucault prism. Design A Glan–Thompson prism consists of two right-angled calcite prisms that are cemented together by their long faces. The optical axes of the calcite crystals are parallel and aligned perpendicular to the plane of reflection. Birefringence splits light entering the prism into two rays, experiencing different refractive indices; the ''p''-polarized ordinary ray is totally internally reflected from the calcite–cement interface, leaving the ''s''-polarized extraordinary ray to be transmitted. The prism can therefore be used as a polarizing beam splitter. Traditionally Canada balsam was used as the cement in assembling these prisms, but this has largely been replaced by synthetic polymers. Characteristics Compared to the similar Glan–Foucault prism, the Glan–Thompson has a wider acceptance angle, but a much lower limit of maximal irradiance In radiometry, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Pockels Cell
In optics, the Pockels effect, or Pockels electro-optic effect, is a directionally-dependent linear variation in the refractive index of an optical medium that occurs in response to the application of an electric field. It is named after the German physicist Friedrich Carl Alwin Pockels, who studied the effect in 1893. The non-linear counterpart, the Kerr effect, causes changes in the refractive index at a rate proportional to the square of the applied electric field. In optical media, the Pockels effect causes changes in birefringence that vary in proportion to the strength of the applied electric field. The Pockels effect occurs in crystals that lack inversion symmetry, such as monopotassium phosphate (, abbr. KDP), potassium dideuterium phosphate (, abbr. KD*P or DKDP), lithium niobate (), beta-barium borate (BBO), barium titanate (BTO) and in other non-centrosymmetric media such as electric-field poled polymers or glasses. The Pockels effect has been elucidated through e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mach–Zehnder Interferometer
The Mach–Zehnder interferometer is a device used to determine the relative phase shift variations between two collimated beams derived by splitting light from a single source. The interferometer has been used, among other things, to measure phase shifts between the two beams caused by a sample or a change in length of one of the paths. The apparatus is named after the physicists Ludwig Mach (the son of Ernst Mach) and Ludwig Zehnder; Zehnder's proposal in an 1891 article was refined by Mach in an 1892 article. Mach–Zehnder interferometry has been demonstrated with electrons as well as with light. The versatility of the Mach–Zehnder configuration has led to its being used in a range of research topics efforts especially in fundamental quantum mechanics. Design The Mach–Zehnder interferometer is a highly configurable instrument. In contrast to the well-known Michelson interferometer, each of the well-separated light paths is traversed only once. If the source ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Interferometer
Interferometry is a technique which uses the '' interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber optics, engineering metrology, optical metrology, oceanography, seismology, spectroscopy (and its applications to chemistry), quantum mechanics, nuclear and particle physics, plasma physics, biomolecular interactions, surface profiling, microfluidics, mechanical stress/strain measurement, velocimetry, optometry, and making holograms. Interferometers are devices that extract information from interference. They are widely used in science and industry for the measurement of microscopic displacements, refractive index changes and surface irregularities. In the case with most interferometers, light from a single source is split into two beams that travel in different optical paths, which are then combined again to produce interference; two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Niels Bohr
Niels Henrik David Bohr (, ; ; 7 October 1885 – 18 November 1962) was a Danish theoretical physicist who made foundational contributions to understanding atomic structure and old quantum theory, quantum theory, for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and a promoter of scientific research. Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another. Although the Bohr model has been supplanted by other models, its underlying principles remain valid. He conceived the principle of Complementarity (physics), complementarity: that items could be separately analysed in terms of contradictory properties, like behaving as a Wave–particle duality, wave or a stream of particles. The notion of complementarity dominated Bohr's thinking in both science and philoso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Albert Einstein
Albert Einstein (14 March 187918 April 1955) was a German-born theoretical physicist who is best known for developing the theory of relativity. Einstein also made important contributions to quantum mechanics. His mass–energy equivalence formula , which arises from special relativity, has been called "the world's most famous equation". He received the 1921 Nobel Prize in Physics for . Born in the German Empire, Einstein moved to Switzerland in 1895, forsaking his German citizenship (as a subject of the Kingdom of Württemberg) the following year. In 1897, at the age of seventeen, he enrolled in the mathematics and physics teaching diploma program at the Swiss ETH Zurich, federal polytechnic school in Zurich, graduating in 1900. He acquired Swiss citizenship a year later, which he kept for the rest of his life, and afterwards secured a permanent position at the Swiss Patent Office in Bern. In 1905, he submitted a successful PhD dissertation to the University of Zurich. In 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Wojciech H
Wojciech () is a Polish name, equivalent to Czech Vojtěch , Slovak Vojtech, and German Woitke. The name is formed from two Slavic roots: * ''wój'' (Slavic: ''voj''), a root pertaining to war. It also forms words like ''wojownik'' ("warrior") and ''wojna'' ("war"). * ''ciech'' (from an earlier form, ''tech''), meaning "joy". The resulting combination means "he who enjoys war" or "joyous warrior". Its Polish diminutive forms include ''Wojtek'' , ''Wojtuś'' , ''Wojtas'', ''Wojcio'', ''Wojteczek'', ''Wojcieszek'', ''Wojtaszka'', ''Wojtaszek'', ''Wojan'' (noted already in 1136), ''Wojko'', and variants noted as early as 1400, including ''Woytko'', ''Woythko'', and ''Voytko''. The feminine form is Wojciecha (). Related names in South Slavic languages include ''Vojko'', ''Vojislav'', and ''Vojteh''. The name has been rendered into German in several different variations, including: ''Woitke'', ''Witke'', ''Voitke'', ''Voytke'', ''Woytke'', ''Vogtke'', ''Woytegk'', ''Woytek'', ''Wogtk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Quantum Potential
The quantum potential or quantum potentiality is a central concept of the de Broglie–Bohm formulation of quantum mechanics, introduced by David Bohm in 1952. Initially presented under the name ''quantum-mechanical potential'', subsequently ''quantum potential'', it was later elaborated upon by Bohm and Basil Hiley in its interpretation as an information potential which acts on a quantum particle. It is also referred to as ''quantum potential energy'', ''Bohm potential'', ''quantum Bohm potential'' or ''Bohm quantum potential''. In the framework of the de Broglie–Bohm theory, the quantum potential is a term within the Schrödinger equation which acts to guide the movement of quantum particles. The quantum potential approach introduced by Bohmfull text)full text) provides a physically less fundamental exposition of the idea presented by Louis de Broglie: de Broglie had postulated in 1925 that the relativistic wave function defined on spacetime represents a pilot wave which gui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
