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No-cloning Theorem
In physics, the no-cloning theorem states that it is impossible to create an independent and identical copy of an arbitrary unknown quantum state, a statement which has profound implications in the field of quantum computer, quantum computing among others. The theorem is an evolution of the 1970 no-go theorem authored by James L. Park, in which he demonstrates that a non-disturbing measurement scheme which is both simple and perfect cannot exist (the same result would be independently derived in 1982 by William Wootters and Wojciech H. Zurek as well as Dennis Dieks the same year). The aforementioned theorems do not preclude the state of one system becoming quantum entanglement, entangled with the state of another as cloning specifically refers to the creation of a separable state with identical factors. For example, one might use the controlled NOT gate and the Hadamard transform#Quantum computing applications, Walsh–Hadamard gate to entangle two qubits without violating the no-cl ... [...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] |
No-broadcast Theorem
In physics, the no-broadcasting theorem is a result of quantum information theory. In the case of pure quantum states, it is a corollary of the no-cloning theorem. The no-cloning theorem for pure states says that it is impossible to create two copies of an unknown state given a single copy of the state. Since quantum states cannot be copied in general, they cannot be broadcast. Here, the word "broadcast" is used in the sense of conveying the state to two or more recipients. For multiple recipients to each receive the state, there must be, in some sense, a way of duplicating the state. The no-broadcast theorem generalizes the no-cloning theorem for mixed states. The theorem also includes a converse: if two quantum states do commute, there is a method for broadcasting them: they must have a common basis of eigenstates diagonalizing them simultaneously, and the map that clones every state of this basis is a legitimate quantum operation, requiring only physical resources indepe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Measurement In Quantum Mechanics
In quantum physics, a measurement is the testing or manipulation of a physical system to yield a numerical result. A fundamental feature of quantum theory is that the predictions it makes are probabilistic. The procedure for finding a probability involves combining a quantum state, which mathematically describes a quantum system, with a mathematical representation of the measurement to be performed on that system. The formula for this calculation is known as the Born rule. For example, a quantum particle like an electron can be described by a quantum state that associates to each point in space a complex number called a probability amplitude. Applying the Born rule to these amplitudes gives the probabilities that the electron will be found in one region or another when an experiment is performed to locate it. This is the best the theory can do; it cannot say for certain where the electron will be found. The same quantum state can also be used to make a prediction of how the electro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Operation
In quantum mechanics, a quantum operation (also known as quantum dynamical map or quantum process) is a mathematical formalism used to describe a broad class of transformations that a quantum mechanical system can undergo. This was first discussed as a general stochastic transformation for a density matrix by George Sudarshan. The quantum operation formalism describes not only unitary time evolution or symmetry transformations of isolated systems, but also the effects of measurement and transient interactions with an environment. In the context of quantum computation, a quantum operation is called a quantum channel. Note that some authors use the term "quantum operation" to refer specifically to completely positive (CP) and non-trace-increasing maps on the space of density matrices, and the term "quantum channel" to refer to the subset of those that are strictly trace-preserving. Quantum operations are formulated in terms of the density operator description of a quantum mechanic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tensor Product
In mathematics, the tensor product V \otimes W of two vector spaces V and W (over the same field) is a vector space to which is associated a bilinear map V\times W \rightarrow V\otimes W that maps a pair (v,w),\ v\in V, w\in W to an element of V \otimes W denoted . An element of the form v \otimes w is called the tensor product of v and w. An element of V \otimes W is a tensor, and the tensor product of two vectors is sometimes called an ''elementary tensor'' or a ''decomposable tensor''. The elementary tensors span V \otimes W in the sense that every element of V \otimes W is a sum of elementary tensors. If bases are given for V and W, a basis of V \otimes W is formed by all tensor products of a basis element of V and a basis element of W. The tensor product of two vector spaces captures the properties of all bilinear maps in the sense that a bilinear map from V\times W into another vector space Z factors uniquely through a linear map V\otimes W\to Z (see the section below ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bra–ket Notation
Bra–ket notation, also called Dirac notation, is a notation for linear algebra and linear operators on complex vector spaces together with their dual space both in the finite-dimensional and infinite-dimensional case. It is specifically designed to ease the types of calculations that frequently come up in quantum mechanics. Its use in quantum mechanics is quite widespread. Bra–ket notation was created by Paul Dirac in his 1939 publication ''A New Notation for Quantum Mechanics''. The notation was introduced as an easier way to write quantum mechanical expressions. The name comes from the English word "bracket". Quantum mechanics In quantum mechanics and quantum computing, bra–ket notation is used ubiquitously to denote quantum states. The notation uses angle brackets, and , and a vertical bar , to construct "bras" and "kets". A ket is of the form , v \rangle. Mathematically it denotes a vector, \boldsymbol v, in an abstract (complex) vector space V, and physicall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Journal Of Physics
The ''American Journal of Physics'' is a monthly, peer-reviewed scientific journal published by the American Association of Physics Teachers and the American Institute of Physics. The editor-in-chief is Beth Parks of Colgate University."Current Frequency: Monthly, 2002; and Former Frequency varies, 1940-2001" Confirmation of Editor, ISSN, CODEN, and other relevant information. Aims and scope The focus of this journal is undergraduate and graduate level physics. The intended audience is college and university physics teachers and students. Coverage includes current research in physics, instructional laboratory equipment, laboratory demonstrations, teaching methodologies, lists of resources, and book reviews. In addition, historical, philosophical and cultural aspects of physics are also covered. According to the 2021 Journal Citation Reports from Clarivate, this journal has a 2020 impact factor of 1.022. History The former title of this journal was ''American Physics Teach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giancarlo Ghirardi
Giancarlo Ghirardi (28 October 1935 – 1 June 2018) was an Italian physicist and emeritus professor of theoretical physics at the University of Trieste. He is well known for the Ghirardi–Rimini–Weber theory (GRW), which he proposed in 1985 together with Alberto Rimini and Tullio Weber, and for his contributions to the foundations of quantum mechanics. He independently rederived, in a referee report to ''Foundations of Physics'', the no-cloning theorem, before the works by William Wootters and Wojciech H. Zurek and by Dennis Dieks in 1982, but after the actual first derivation by James L. Park in 1970. His research interests related to a variety of topics of theoretical physics, but focused beginning in 1983 mainly on the foundations of quantum mechanics. Ghirardi was a member of the editorial boards of ''Foundations of Physics'' and '' Studies in History and Philosophy of Science''. He was president of the Italian Society for the Foundations of Physics, of which he was o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superluminal Communication
Faster-than-light communication, also called superluminal communication, is a hypothetical process in which information is conveyed at faster-than-light speeds. The current scientific consensus is that faster-than-light communication is not possible, and to date it has not been achieved in any experiment. Faster-than-light communication other than possibly through wormholes is likely impossible because, in a Lorentz-invariant theory, it could be used to transmit information into the past. This would complicate causality, but no theoretical arguments conclusively preclude this possibility. A number of theories and phenomena related to faster-than-light communication have been proposed or studied, including tachyons, neutrinos, quantum nonlocality, wormholes, and quantum tunneling. Proposed mechanisms Tachyons Tachyonic particles are hypothetical particles that travel faster than light, which could conceivably allow for superluminal communication. Because such a particle wou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nick Herbert (physicist)
Nick Herbert (born September 7, 1936) is an American physicist and author, best known for his book '' Quantum Reality''. Biography Herbert studied engineering physics at The Ohio State University, graduating in 1959. He received a Ph.D. in physics from Stanford University in 1967 for work on nuclear scattering experiments. After a one-year teaching job at Monmouth College in Illinois, Herbert held a number of posts in industry. The most illustrious of these was senior physicist at Memorex Corporation in Santa Clara, California, where he developed new magnetic materials, as well as magnetic, electrostatic and optical measuring devices, and carried out theoretical work on Lorentz microscopy. He was also senior physicist at Smith-Corona Marchant Corporation in Palo Alto, California where he developed a new theory of xerographic process and worked on early developments in ink jet printing. While employed in industry, Herbert was part of the Fundamental Fysiks Group at Lawrence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Kaiser (physicist)
David I. Kaiser is an American physicist and historian of science. He is Germeshausen Professor of the History of Science at the Massachusetts Institute of Technology (MIT) and a full professor in MIT's department of physics. He also served as an inaugural associate dean for MIT's cross-disciplinary program in Social and Ethical Responsibilities of Computing. Kaiser is the author or editor of several books on the history of science, including ''Drawing Theories Apart: The Dispersion of Feynman Diagrams in Postwar Physics'' (2005), ''How the Hippies Saved Physics: Science, Counterculture, and the Quantum Revival'' (2011), and ''Quantum Legacies: Dispatches from an Uncertain World'' (2020). He received the Apker Award from the American Physical Society in 1993 and was elected a Fellow of the American Physical Society in 2010. His historical scholarship has been honored with the Pfizer Award (2007)History of Science Society"Pfizer Award" and the Davis Prize (2013)History of Science So ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fortschritte Der Physik
The German Physical Society (German: , DPG) is the oldest organisation of physicists. As of 2022, the DPG's worldwide membership is cited as 52,220, making it one of the largest national physics societies in the world. The DPG's membership peaked in 2014 when it reached 63,000, but it has been decreasing since then. It holds an annual conference () and multiple spring conferences (), which are held at various locations and along topical subjects of given sections of the DPG. The DPG concerns the fields of pure and applied physics and aims to foster connections among German physicists, as well as the exchange of ideas between its members and foreign colleagues. The bylaws of the DPG commit the organization and its members to maintain scientific integrity and ethics, including freedom, tolerance, truthfulness, and dignity in scientific work, as well as the promotion of gender equality in the fields of physics and related sciences. Conferences The DPG itself does not carry out any r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
