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Quantum Speed Limit
In quantum mechanics, a quantum speed limit (QSL) is a limitation on the minimum time for a quantum system to evolve between two distinguishable states. QSL are closely related to time-energy uncertainty relations. In 1945, Leonid Mandelstam and Igor Tamm derived a time-energy uncertainty relation that bounds the speed of evolution in terms of the energy dispersion. Over half a century later, Norman Margolus and Lev Levitin showed that the speed of evolution cannot exceed the mean energy, a result known as the Margolus–Levitin theorem. Realistic physical systems in contact with an environment are known as open quantum systems and their evolution is also subject to QSL. Quite remarkably it was shown that environmental effects, such as non-Markovian dynamics can speed up quantum processes, which was verified in a cavity QED experiment. QSL have been used to explore the limits of computation The limits of computation are governed by a number of different factors. In particular, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Mechanics
Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, quantum field theory, quantum technology, and quantum information science. Classical physics, the collection of theories that existed before the advent of quantum mechanics, describes many aspects of nature at an ordinary (macroscopic) scale, but is not sufficient for describing them at small (atomic and subatomic) scales. Most theories in classical physics can be derived from quantum mechanics as an approximation valid at large (macroscopic) scale. Quantum mechanics differs from classical physics in that energy, momentum, angular momentum, and other quantities of a bound system are restricted to discrete values ( quantization); objects have characteristics of both particles and waves (wave–particle duality); and there are limits to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Math
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics with the major subdisciplines of number theory, algebra, geometry, and analysis, respectively. There is no general consensus among mathematicians about a common definition for their academic discipline. Most mathematical activity involves the discovery of properties of abstract objects and the use of pure reason to prove them. These objects consist of either abstractions from nature orin modern mathematicsentities that are stipulated to have certain properties, called axioms. A ''proof'' consists of a succession of applications of deductive rules to already established results. These results include previously proved theorems, axioms, andin case of abstraction from naturesome basic properties that are considered true starting points of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonid Mandelstam
Leonid Isaakovich Mandelstam or Mandelshtam ( be, Леанід Ісаакавіч Мандэльштам; rus, Леонид Исаакович Мандельштам, p=lʲɪɐˈnʲit ɨsɐˈakəvʲɪtɕ mənʲdʲɪlʲˈʂtam, a=Ru-Leonid_Mandelstam.ogg, links=y; 4 May 1879 – 27 November 1944) was a Soviet physicist of Belarusian-Jewish background. Life Leonid Mandelstam was born in Mogilev, Russian Empire (now Belarus). He studied at the Novorossiya University in Odessa, but was expelled in 1899 due to political activities, and continued his studies at the University of Strasbourg. He remained in Strasbourg until 1914, and returned with the beginning of World War I. He was awarded the Stalin Prize in 1942. Mandelstam died in Moscow, USSR (now Russia). Scientific achievements The main emphasis of his work was broadly considered theory of oscillations, which included optics and quantum mechanics. He was a co-discoverer of inelastic ''combinational scattering of light'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Igor Tamm
Igor Yevgenyevich Tamm ( rus, И́горь Евге́ньевич Тамм , p=ˈiɡərʲ jɪvˈɡʲenʲjɪvitɕ ˈtam , a=Ru-Igor Yevgenyevich Tamm.ogg; 8 July 1895 – 12 April 1971) was a Soviet physicist who received the 1958 Nobel Prize in Physics, jointly with Pavel Alekseyevich Cherenkov and Ilya Mikhailovich Frank, for their 1934 discovery and demonstration of Cherenkov radiation. He also predicted the Quasi-particle Phonon, and in 1951, together with Andrei Sakharov were the proposers of the Tokamak system. Biography According to Russian sources, Tamm had German noble descent on his father's side through his grandfather Theodor Tamm, who emigrated from Thuringia. Although his surname "Tamm" is rather common in Estonia, other sources state he was Jewish or had Jewish ancestry. He studied at a gymnasium in Elisavetgrad (now Kropyvnytskyi, Ukraine). In 1913–1914 he studied at the University of Edinburgh together with his school-friend Boris Hessen. At the outbreak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norman Margolus
Norman H. Margolus (born 1955) is a Canadian-American physicist and computer scientist, known for his work on cellular automata and reversible computing.. He is a research affiliate with the Computer Science and Artificial Intelligence Laboratory at the Massachusetts Institute of Technology. Education and career Margolus received his Ph.D. in physics in 1987 from the Massachusetts Institute of Technology (MIT) under the supervision of Edward Fredkin. He founded and was chief scientist for Permabit, an information storage device company. Research contributions Margolus was one of the organizers of a seminal research meeting on the connections between physics and computation theory, held on Mosquito Island in 1982. He is known for inventing the block cellular automaton and the Margolus neighborhood for block cellular automata, which he used to develop cellular automaton simulations of billiard-ball computers.. Reprinted in . In the same work, Margolus also showed that the bil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lev Levitin
Lev B. Levitin is a Russian-American engineer currently a Distinguished Professor at Boston University and a Life Fellow of the IEEE. His current research interests include information theory, physical aspects of computation, complex systems and quantum measurement. He is known for the Margolus–Levitin theorem The Margolus–Levitin theorem states that the processing rate of all forms of computation (including quantum computation) cannot be higher than about 6 × 1033 operations per second per joule of energy. The theorem is named for Norman Margol .... References Year of birth missing (living people) Living people Boston University faculty Fellow Members of the IEEE Russian engineers American electrical engineers {{US-electrical-engineer-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonlinear Phenomena
In mathematics and science, a nonlinear system is a system in which the change of the output is not proportional to the change of the input. Nonlinear problems are of interest to engineers, biologists, physicists, mathematicians, and many other scientists because most systems are inherently nonlinear in nature. Nonlinear dynamical systems, describing changes in variables over time, may appear chaotic, unpredictable, or counterintuitive, contrasting with much simpler linear systems. Typically, the behavior of a nonlinear system is described in mathematics by a nonlinear system of equations, which is a set of simultaneous equations in which the unknowns (or the unknown functions in the case of differential equations) appear as variables of a polynomial of degree higher than one or in the argument of a function which is not a polynomial of degree one. In other words, in a nonlinear system of equations, the equation(s) to be solved cannot be written as a linear combination of the un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Margolus–Levitin Theorem
The Margolus–Levitin theorem states that the processing rate of all forms of computation (including quantum computation) cannot be higher than about 6 × 1033 operations per second per joule of energy. The theorem is named for Norman Margolus and Lev B. Levitin, who derived this fundamental limit on the rate of computation. Stating the bound for one bit is as follows: :A quantum system of energy ''E'' needs at least a time of \frac to go from one state to an orthogonal state, where ''h'' is the Planck constant () and ''E'' is average energy. See also * Bekenstein bound * Bremermann's limit * Landauer's principle * Kolmogorov complexity * Koomey's law * Limits to computation * Moore's law References * * * * Lloyd, Seth; Ng, Y. Jack,Black Hole Computers, ''Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Quantum System
In physics, an open quantum system is a quantum-mechanical system that interacts with an external quantum system, which is known as the ''environment'' or a ''bath''. In general, these interactions significantly change the dynamics of the system and result in quantum dissipation, such that the information contained in the system is lost to its environment. Because no quantum system is completely isolated from its surroundings, it is important to develop a theoretical framework for treating these interactions in order to obtain an accurate understanding of quantum systems. Techniques developed in the context of open quantum systems have proven powerful in fields such as quantum optics, quantum measurement theory, quantum statistical mechanics, quantum information science, quantum thermodynamics, quantum cosmology, quantum biology, and semi-classical approximations. Quantum system and environment A complete description of a quantum system requires the inclusion of the environment. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Review Letters
''Physical Review Letters'' (''PRL''), established in 1958, is a peer-reviewed, scientific journal that is published 52 times per year by the American Physical Society. As also confirmed by various measurement standards, which include the ''Journal Citation Reports'' impact factor and the journal ''h''-index proposed by Google Scholar, many physicists and other scientists consider ''Physical Review Letters'' to be one of the most prestigious journals in the field of physics. ''According to Google Scholar, PRL is the journal with the 9th journal h-index among all scientific journals'' ''PRL'' is published as a print journal, and is in electronic format, online and CD-ROM. Its focus is rapid dissemination of significant, or notable, results of fundamental research on all topics related to all fields of physics. This is accomplished by rapid publication of short reports, called "Letters". Papers are published and available electronically one article at a time. When published in s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limits Of Computation
The limits of computation are governed by a number of different factors. In particular, there are several physical and practical limits to the amount of computation or data storage that can be performed with a given amount of mass, volume, or energy. Hardware limits or physical limits Processing and memory density * The Bekenstein bound limits the amount of information that can be stored within a spherical volume to the entropy of a black hole with the same surface area. * Thermodynamics limit the data storage of a system based on its energy, number of particles and particle modes. In practice, it is a stronger bound than the Bekenstein bound. Processing speed * Bremermann's limit is the maximum computational speed of a self-contained system in the material universe, and is based on mass–energy versus quantum uncertainty constraints. Communication delays * The Margolus–Levitin theorem sets a bound on the maximum computational speed per unit of energy: 6 × 1033 op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Journal Of Physics
''New Journal of Physics'' is an online-only, open-access, peer-reviewed scientific journal covering research in all aspects of physics, as well as interdisciplinary topics where physics forms the central theme. The journal was established in 1998 and is a joint publication of the Institute of Physics and the Deutsche Physikalische Gesellschaft. It is published by IOP Publishing. The editor-in-chief An editor-in-chief (EIC), also known as lead editor or chief editor, is a publication's editorial leader who has final responsibility for its operations and policies. The highest-ranking editor of a publication may also be titled editor, managing ... is Andreas Buchleitner ( Albert Ludwigs University). ''New Journal of Physics'' is part of the SCOAP3 initiative. Abstracting and indexing The journal is indexed and abstracted in: References External links * {{Official website, http://iopscience.iop.org/1367-2630 Open access journals Physics journals IOP Publishing academic j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
