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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 are attempts to decide whether light somehow "senses" the experimental apparatus in the double-slit experiment it travels through, adjusting its behavior to fit by assuming the appropriate determinate state for it, or whether light remains in an indeterminate state, exhibiting both wave-like and particle-like behavior until measured. The common intention of these several types of experiments is to first do something that, according to some hidden-variable models, would make each photon "decide" whether it was going to behave as a particle or behave as a wave, and then, before the photon had time to reach the detection device, create another change in the system that would make it seem that the photon had "chosen" to behave in the opposite way. Some interpreters of these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Archibald Wheeler 1985
John is a common English name and surname: * John (given name) * John (surname) John may also refer to: New Testament Works * Gospel of John, a title often shortened to John * First Epistle of John, often shortened to 1 John * Second Epistle of John, often shortened to 2 John * Third Epistle of John, often shortened to 3 John People * John the Baptist (died c. AD 30), regarded as a prophet and the forerunner of Jesus Christ * John the Apostle (lived c. AD 30), one of the twelve apostles of Jesus * John the Evangelist, assigned author of the Fourth Gospel, once identified with the Apostle * John of Patmos, also known as John the Divine or John the Revelator, the author of the Book of Revelation, once identified with the Apostle * John the Presbyter, a figure either identified with or distinguished from the Apostle, the Evangelist and John of Patmos Other people with the given name Religious figures * John, father of Andrew the Apostle and Saint Peter * Pope John ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wheeler Astro Lab Beam-splitterVersion
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, A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delayed-choice Quantum Eraser
A delayed-choice quantum eraser experiment, first performed by Yoon-Ho Kim, R. Yu, S. P. Kulik, Y. H. Shih and Marlan O. Scully, and reported in early 1998, is an elaboration on the quantum eraser experiment that incorporates concepts considered in John Archibald Wheeler's delayed-choice experiment. The experiment was designed to investigate peculiar consequences of the well-known double-slit experiment in quantum mechanics, as well as the consequences of quantum entanglement. The delayed-choice quantum eraser experiment investigates a paradox. If a photon manifests itself as though it had come by a single path to the detector, then "common sense" (which Wheeler and others challenge) says that it must have entered the double-slit device as a ''particle''. If a photon manifests itself as though it had come by two indistinguishable paths, then it must have entered the double-slit device as a ''wave''. Accordingly, if the experimental apparatus is changed while the photon is in mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SETI
The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other planets. Scientific investigation began shortly after the advent of radio in the early 1900s, and focused international efforts have been ongoing since the 1980s. In 2015, Stephen Hawking and Israeli billionaire Yuri Milner announced a project called Breakthrough Listen. History Early work There have been many earlier searches for extraterrestrial intelligence within the Solar System. In 1896, Nikola Tesla suggested that an extreme version of his wireless electrical transmission system could be used to contact beings on Mars. In 1899, while conducting experiments at his Colorado Springs experimental station, he thought he had detected a signal from Mars since an odd repetitive static signal seemed to cut off when Mars set in the night ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glan–Thompson Prism
A Glan–Thompson prism is a type of polarizing prism similar to the Nicol and Glan–Foucault prisms. 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 (due to optical damage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pockels Cell
The Pockels effect or Pockels electro-optic effect, named after Friedrich Carl Alwin Pockels (who studied the effect in 1893), changes or produces birefringence in an optical medium induced by an electric field. In the Pockels effect, also known as the linear electro-optic effect, the birefringence is proportional to the electric field. In the Kerr effect, the refractive index change (birefringence) is proportional to the square of the field. The Pockels effect occurs only in crystals that lack inversion symmetry, such as KH2PO4 (KDP), KD2PO4 (KD*P or DKDP), lithium niobate (LiNbO3), and in other non-centrosymmetric media such as electric-field poled polymers or glasses. The electro-optic properties of materials like KDP and its isomorphs that exhibits that Pockels effect has been extensively studied over the years to allow accurate models for simulations. Pockels cells Pockels cells are voltage-controlled wave plates. The Pockels effect is the basis of the operation of Pockels ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Demonstrations of Mach–Zehnder interferometry with particles other than photons (particles of light) had been demonstrated as well in multiple experiments. The versatility of the Mach–Zehnder configuration has led to its being used in a wide range of fundamental research topics in quantum mechanics, including studies on counterfactual definiteness, quantum entanglement, quantum computation, quantum cryptography, quantum logic, Elitzur–Vaidman bomb tester, the quant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, remote sensing, 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 in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 gu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
