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Non-Hermitian Quantum Mechanics
In physics, non-Hermitian quantum mechanics describes quantum mechanical systems where Hamiltonians are not Hermitian. History The first paper that has "non-Hermitian quantum mechanics" in the title was published in 1996 by Naomichi Hatano and David R. Nelson. The authors mapped a classical statistical model of flux-line pinning by columnar defects in high-Tc superconductors to a quantum model by means of an inverse path-integral mapping and ended up with a non-Hermitian Hamiltonian with an imaginary vector potential in a random scalar potential. They further mapped this into a lattice model and came up with a tight-binding model with asymmetric hopping, which is now widely called the Hatano-Nelson model. The authors showed that there is a region where all eigenvalues are real despite the non-Hermiticity. Parity–time (PT) symmetry was initially studied as a specific system in non-Hermitian quantum mechanics. In 1998, physicist Carl Bender and former graduate student Stefa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics
Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events." It is one of the most fundamental scientific disciplines. "Physics is one of the most fundamental of the sciences. Scientists of all disciplines use the ideas of physics, including chemists who study the structure of molecules, paleontologists who try to reconstruct how dinosaurs walked, and climatologists who study how human activities affect the atmosphere and oceans. Physics is also the foundation of all engineering and technology. No engineer could design a flat-screen TV, an interplanetary spacecraft, or even a better mousetrap without first understanding the basic laws of physics. (...) You will come to see physics as a towering achievement of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Dirac
Paul Adrien Maurice Dirac ( ; 8 August 1902 – 20 October 1984) was an English mathematician and Theoretical physics, theoretical physicist who is considered to be one of the founders of quantum mechanics. Dirac laid the foundations for both quantum electrodynamics and quantum field theory. He was the Lucasian Professor of Mathematics at the University of Cambridge and a professor of physics at Florida State University. Dirac shared the 1933 Nobel Prize in Physics with Erwin Schrödinger for "the discovery of new productive forms of atomic theory". Dirac graduated from the University of Bristol with a first class honours Bachelor of Science degree in electrical engineering in 1921, and a first class honours Bachelor of Arts degree in mathematics in 1923. Dirac then graduated from the University of Cambridge with a PhD in physics in 1926, writing the first ever thesis on quantum mechanics. Dirac made fundamental contributions to the early development of both quantum mechanic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorje C
The Vajra (, , ), is a legendary and ritualistic tool, symbolizing the properties of a diamond (indestructibility) and a thunderbolt (irresistible force). It is also described as a "ritual weapon". The use of the bell and vajra together as symbolic and ritual tools is found in all schools of Tibetan Buddhism. The vajra is a round, symmetrical metal scepter with two ribbed spherical heads. The ribs may meet in a ball-shaped top, or they may be separate and end in sharp points. The vajra is considered inseparable from the bell, and both are sold in dharma stores only in matching sets. The bell is also metal with a ribbed spherical head. The bell also depicts the face of Dhatvisvari, a female buddha and the consort of Akshobhya. The vajra has also been associated as the weapon of Indra, the Vedic king of the devas and heaven. It is used symbolically by the dharmic traditions of Hinduism, Buddhism, and Jainism, often to represent firmness of spirit and spiritual power. Accordi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Magnetic Resonance
Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are disturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with a frequency characteristic of the magnetic field at the nucleus. This process occurs near resonance, when the oscillation frequency matches the intrinsic frequency of the nuclei, which depends on the strength of the static magnetic field, the chemical environment, and the magnetic properties of the isotope involved; in practical applications with static magnetic fields up to ca. 20 tesla, the frequency is similar to VHF and UHF television broadcasts (60–1000 MHz). NMR results from specific magnetic properties of certain atomic nuclei. High-resolution nuclear magnetic resonance spectroscopy is widely used to determine the structure of organic molecules in solution and study molecular physics and crystals as well as non-crysta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Circuit
An electrical network is an interconnection of electrical components (e.g., battery (electricity), batteries, resistors, inductors, capacitors, switches, transistors) or a model of such an interconnection, consisting of electrical elements (e.g., voltage sources, current sources, Electrical resistance and conductance, resistances, inductances, capacitances). An electrical circuit is a network consisting of a closed loop, giving a return path for the current. Thus all circuits are networks, but not all networks are circuits (although networks without a closed loop are often referred to as "open circuits"). A resistive network is a network containing only resistors and ideal current and voltage sources. Network analysis (electrical circuits), Analysis of resistive networks is less complicated than analysis of networks containing capacitors and inductors. If the sources are constant (Direct current, DC) sources, the result is a DC network. The effective resistance and current dist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamaterial
A metamaterial (from the Greek word μετά ''meta'', meaning "beyond" or "after", and the Latin word ''materia'', meaning "matter" or "material") is a type of material engineered to have a property, typically rarely observed in naturally occurring materials, that is derived not from the properties of the base materials but from their newly designed structures. Metamaterials are usually fashioned from multiple materials, such as metals and plastics, and are usually arranged in repeating patterns, at scales that are smaller than the wavelengths of the phenomena they influence. Their precise shape, geometry, size, orientation, and arrangement give them their "smart" properties of manipulating electromagnetic, acoustic, or even seismic waves: by blocking, absorbing, enhancing, or bending waves, to achieve benefits that go beyond what is possible with conventional materials. Appropriately designed metamaterials can affect waves of electromagnetic radiation or sound in a manner n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classical Mechanics
Classical mechanics is a Theoretical physics, physical theory describing the motion of objects such as projectiles, parts of Machine (mechanical), machinery, spacecraft, planets, stars, and galaxies. The development of classical mechanics involved Scientific Revolution, substantial change in the methods and philosophy of physics. The qualifier ''classical'' distinguishes this type of mechanics from physics developed after the History of physics#20th century: birth of modern physics, revolutions in physics of the early 20th century, all of which revealed limitations in classical mechanics. The earliest formulation of classical mechanics is often referred to as Newtonian mechanics. It consists of the physical concepts based on the 17th century foundational works of Sir Isaac Newton, and the mathematical methods invented by Newton, Gottfried Wilhelm Leibniz, Leonhard Euler and others to describe the motion of Physical body, bodies under the influence of forces. Later, methods bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demetrios N
Demetrius is the Latinized form of the Ancient Greek male given name ''Dēmḗtrios'' (), meaning "devoted to goddess Demeter". Alternate forms include Demetrios, Dimitrios, Dimitris, Dmytro, Dimitri, Dimitrie, Dimitar, Dumitru, Demitri, Dhimitër, Dimitrije and Zmicier, in addition to other forms (such as Russian Dmitry) descended from it. Nicknames include Demmie, Dimmie, Demi, Jim, Jimmy, Jimmie, Metry, Metrie, Mimmie, Demetri, Dmitri, Mitică, Mitya and Dima. Demetrius and its variations may refer to the following: Real people Ancient *Demetrius of Alopece, 4th century BC Greek sculptor noted for his realism *Demetrius of Phalerum ( – BC) *Demetrius (somatophylax), somatophylax of Alexander the Great (d. 330 BC) *Demetrius I of Macedon (337–283 BC), called ''Poliorcetes'', son of Antigonus I Monophthalmus, King of Macedonia 294–288 BC *Demetrius the Fair (Demetrius the Handsome, Demetrius of Cyrene) (285 BC-249/250 BC) - Hellenistic king of Cyrene *Demetrius I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mark Krein
Mark Grigorievich Krein (, ; 3 April 1907 – 17 October 1989) was a Soviet mathematician, one of the major figures of the Soviet school of functional analysis. He is known for works in operator theory (in close connection with concrete problems coming from mathematical physics), the problem of moments, classical analysis and representation theory. He was born in Kyiv, leaving home at age 17 to go to Odesa. He had a difficult academic career, not completing his first degree and constantly being troubled by anti-Semitic discrimination. His supervisor was Nikolai Chebotaryov. He was awarded the Wolf Prize in Mathematics in 1982 (jointly with Hassler Whitney), but was not allowed to attend the ceremony. David Milman, Mark Naimark, Israel Gohberg, Vadym Adamyan, Mikhail Livsic and other known mathematicians were his students. He died in Odesa. On 14 January 2008, the memorial plaque of Mark Krein was unveiled on the main administration building of I.I. Mechnikov Odesa Na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gian Carlo Wick
Gian Carlo Wick (15 October 1909 – 20 April 1992) was an Italian theoretical physicist who made important contributions to quantum field theory. The Wick rotation, Wick contraction, Wick's theorem, and the Wick product are named after him.Gian-Carlo Wick, October 15, 1909—April 20, 1992, Maurice Jacob biographical memoir, National Academies Press. Accessed online 6 October 2009. Life Gian Carlo Wick, first name "Gian Carlo", was born in in 1909. Wick's father was a Latinist and Greekist, and his mother, |
Tsung-Dao Lee
Tsung-Dao Lee (; November 24, 1926 – August 4, 2024) was a Chinese-American physicist, known for his work on parity violation, the Lee–Yang theorem, particle physics, relativistic heavy ion (RHIC) physics, nontopological solitons, and soliton stars. He was a university professor emeritus at Columbia University in New York City, where he taught from 1953 until his retirement in 2012. In 1957, at the age of 30, Lee won the Nobel Prize in Physics with Chen Ning Yang for their work on the violation of the parity law in weak interactions, which Chien-Shiung Wu experimentally proved from 1956 to 1957, with her well known Wu experiment. Lee remains the youngest Nobel laureate in the science fields after World War II. He is the third-youngest Nobel laureate in sciences in history after William L. Bragg (who won the prize at 25 with his father William H. Bragg in 1915) and Werner Heisenberg (who won in 1932 also at 30). Lee and Yang were the first Chinese laureates. Sinc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
