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Weak Value
In quantum mechanics (and computation), a weak value is a quantity related to a shift of a measuring device's pointer when usually there is pre- and postselection. It should not be confused with a weak measurement, which is often defined in conjunction. The weak value was first defined by Yakir Aharonov, David Albert, and Lev Vaidman, published in Physical Review Letters 1988, and is related to the two-state vector formalism. There is also a way to obtain weak values without postselection. Definition and Derivation There are many excellent review articles on weak values (see e.g. ) here we briefly cover the basics. Definition We will denote the initial state of a system as , \psi_i\rangle, while the final state of the system is denoted as , \psi_f\rangle. We will refer to the initial and final states of the system as the pre- and post-selected quantum mechanical states. With respect to these states, the ''weak value'' of the observable A is defined as: A_w = \frac. Notice that if ... [...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] |
Quantum Tomography
Quantum tomography or quantum state tomography is the process by which a quantum state is reconstructed using measurements on an ensemble of identical quantum states. The source of these states may be any device or system which prepares quantum states either consistently into quantum pure states or otherwise into general mixed states. To be able to uniquely identify the state, the measurements must be tomographically complete. That is, the measured operators must form an operator basis on the Hilbert space of the system, providing all the information about the state. Such a set of observations is sometimes called a quorum. In quantum process tomography on the other hand, known quantum states are used to probe a quantum process to find out how the process can be described. Similarly, quantum measurement tomography works to find out what measurement is being performed. Whereas, randomized benchmarking scalably obtains a figure of merit of the overlap between the error prone ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discover (magazine)
''Discover'' is an American general audience science magazine launched in October 1980 by Time Inc. It has been owned by Kalmbach Publishing since 2010. History Founding ''Discover'' was created primarily through the efforts of ''Time'' magazine editor Leon Jaroff. He noticed that magazine sales jumped every time the cover featured a science topic. Jaroff interpreted this as a considerable public interest in science, and in 1971, he began agitating for the creation of a science-oriented magazine. This was difficult, as a former colleague noted, because "Selling science to people who graduated to be managers was very difficult".Hevesi, Dennis"Leon Jaroff, Editor at Time and Discover Magazines, Dies at 85" ''The New York Times'', 21 October 2012 Jaroff's persistence finally paid off, and ''Discover'' magazine published its first edition in 1980. ''Discover'' was originally launched into a burgeoning market for science magazines aimed at educated non-professionals, intended to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles H
Charles is a masculine given name predominantly found in English and French speaking countries. It is from the French form ''Charles'' of the Proto-Germanic name (in runic alphabet) or ''*karilaz'' (in Latin alphabet), whose meaning was "free man". The Old English descendant of this word was '' Ċearl'' or ''Ċeorl'', as the name of King Cearl of Mercia, that disappeared after the Norman conquest of England. The name was notably borne by Charlemagne (Charles the Great), and was at the time Latinized as ''Karolus'' (as in ''Vita Karoli Magni''), later also as '' Carolus''. Some Germanic languages, for example Dutch and German, have retained the word in two separate senses. In the particular case of Dutch, ''Karel'' refers to the given name, whereas the noun ''kerel'' means "a bloke, fellow, man". Etymology The name's etymology is a Common Germanic noun ''*karilaz'' meaning "free man", which survives in English as churl (< Old English ''ċeorl''), which developed its de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Mermin
Nathaniel David Mermin (; born 30 March 1935) is a solid-state physicist at Cornell University best known for the eponymous Mermin–Wagner theorem, his application of the term " boojum" to superfluidity, his textbook with Neil Ashcroft on solid-state physics, and for contributions to the foundations of quantum mechanics and quantum information science. Education and career Mermin was born in 1935 in New Haven, Connecticut. He obtained a bachelor's degree in mathematics from Harvard University in 1956, graduating ''summa cum laude.'' He remained at Harvard for his graduate studies, earning a PhD in physics in 1961. After holding postdoctoral positions at the University of Birmingham and the University of California, San Diego, he joined the Cornell University faculty in 1964. He became a Cornell professor emeritus in 2006. Early in his career, Mermin worked in statistical physics and condensed-matter physics, including the study of matter at low temperatures, the behavior of e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthony James Leggett
Sir Anthony James Leggett (born 26 March 1938) is a British-American theoretical physicist and professor emeritus at the University of Illinois at Urbana-Champaign. Leggett is widely recognised as a world leader in the theory of low-temperature physics, and his pioneering work on superfluidity was recognised by the 2003 Nobel Prize in Physics. He has shaped the theoretical understanding of normal and superfluid helium liquids and strongly coupled superfluids. He set directions for research in the quantum physics of macroscopic dissipative systems and use of condensed systems to test the foundations of quantum mechanics. In a 2021 interview given to Federal University of Pará in Brazil, Leggett talks about his early life in London, his path to become a theoretical physicist and also his scientific works and collaborations. Early life and education Leggett was born in Camberwell, South London, and raised Catholic. His father's forebears were village cobblers in a small village ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asher Peres
Asher Peres ( he, אשר פרס; January 30, 1934 – January 1, 2005) was an Israeli physicist. He is well known for his work relating quantum mechanics and information theory. He helped to develop the Peres–Horodecki criterion for quantum entanglement, as well as the concept of quantum teleportation, and collaborated with others on quantum information and special relativity. He also introduced the Peres metric and researched the Hamilton–Jacobi–Einstein equation in general relativity. With Mario Feingold, he published work in quantum chaos that is known to mathematicians as the Feingold–Peres conjecture and to physicists as the Feingold–Peres theory. Life According to his autobiography, he was born ''Aristide Pressman'' in Beaulieu-sur-Dordogne in France, where his father, a Polish electrical engineer, had found work laying down power lines. He was given the name ''Aristide'' at birth, because the name his parents wanted, ''Asher'', the name of his maternal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grover's Algorithm
In quantum computing, Grover's algorithm, also known as the quantum search algorithm, refers to a quantum algorithm for unstructured search that finds with high probability the unique input to a black box function that produces a particular output value, using just O(\sqrt) evaluations of the function, where N is the size of the function's domain. It was devised by Lov Grover in 1996. The analogous problem in classical computation cannot be solved in fewer than O(N) evaluations (because, on average, one has to check half of the domain to get a 50% chance of finding the right input). Charles H. Bennett, Ethan Bernstein, Gilles Brassard, and Umesh Vazirani proved that any quantum solution to the problem needs to evaluate the function \Omega(\sqrt) times, so Grover's algorithm is asymptotically optimal. Since classical algorithms for NP-complete problems require exponentially many steps, and Grover's algorithm provides at most a quadratic speedup over the classical solution for un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arun K
Arun may refer to: People * Arun (given name), including a list of people with that name * Ila Arun, Indian actress * Priya Arun (born 1967), Indian actress * Bharat Arun (born 1962), Indian Test cricketer Places * Arun, Badakhshan, Afghanistan * Arun (England), a region of southeasthern England ** Arun District, West Sussex, England * Arun Banner, an administrative division (banner) of Inner Mongolia, China * Arun, Sumatra, a vassal state, now in Indonesia * Arun gas field, Sumatra, Indonesia * Aran va Bidgol ('Aran and Bidgol'), Isfahan Province, Iran **Aran va Bidgol County * Arun rural municipality, Nepal * Wat Arun, a temple in Bangkok, Thailand Rivers and canals * Arun River, China–Nepal * River Arun, in West Sussex, England * Wey and Arun Canal, in the south east of England Other uses * Aruṇa, a god in Hinduism * ''Arun''-class lifeboat * , two ships of the Royal Navy See also * * * Aaron (other) * Arran (other) * Aruna (other) * Arru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
De Broglie–Bohm Theory
The de Broglie–Bohm theory, also known as the ''pilot wave theory'', Bohmian mechanics, Bohm's interpretation, and the causal interpretation, is an interpretation of quantum mechanics. In addition to the wavefunction, it also postulates an actual configuration of particles exists even when unobserved. The evolution over time of the configuration of all particles is defined by a guiding equation. The evolution of the wave function over time is given by the Schrödinger equation. The theory is named after Louis de Broglie (1892–1987) and David Bohm (1917–1992). The theory is deterministic and explicitly nonlocal: the velocity of any one particle depends on the value of the guiding equation, which depends on the configuration of all the particles under consideration. Measurements are a particular case of quantum processes described by the theory and yields the standard quantum predictions generally associated with the Copenhagen interpretation. The theory does not have a "m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partha Ghose
Partha Ghose (born 1939) is an Indian physicist, author, philosopher, musician and former professor at the S.N. Bose National Centre for Basic Sciences in Kolkata. He is the former Chairman of Satyajit Ray Film and Television Institute, Kolkata and a member of the Board of Trustees of the Academy of Fine Arts, Kolkata. Life and works Partha Ghose is one of India's best known popularizers of modern science. He has written influential papers and booksP. Ghose, Testing Quantum Mechanics on New Ground, Cambridge University Press, UK, April 1999." on physics as well as popular books on science.P. Ghose and D. Home, Riddles in Your Tea Cup, Rupa & Co., 1990, Adam Hilger, UK, Sept 1994. The book has been published in several Indian languages, Italian, Japanese and Turkish.P. Ghose, ''Solar Eclipse : The Celestial Diamond'', Harper-Collins of India, 1996. He was an anchorperson in the popular Indian TV shows Quest and Eureka. He has directed plays and appeared in media programmes an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double-slit Interferometer
In modern physics, the double-slit experiment is a demonstration that light and matter can display characteristics of both classically defined waves and particles; moreover, it displays the fundamentally probabilistic nature of quantum mechanical phenomena. This type of experiment was first performed by Thomas Young in 1801, as a demonstration of the wave behavior of visible light. At that time it was thought that light consisted of ''either'' waves ''or'' particles. With the beginning of modern physics, about a hundred years later, it was realized that light could in fact show behavior characteristic of ''both'' waves ''and'' particles. In 1927, Davisson and Germer 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 wave theory of light ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
