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Quantum Conditional Entropy
The conditional quantum entropy is an entropy measure used in quantum information theory. It is a generalization of the conditional entropy of classical information theory. For a bipartite state \rho^, the conditional entropy is written S(A, B)_\rho, or H(A, B)_\rho, depending on the notation being used for the von Neumann entropy. The quantum conditional entropy was defined in terms of a conditional density operator \rho_ by Nicolas Cerf and Chris Adami, who showed that quantum conditional entropies can be negative, something that is forbidden in classical physics. The negativity of quantum conditional entropy is a sufficient criterion for quantum Separable state, non-separability. In what follows, we use the notation S(\cdot) for the von Neumann entropy, which will simply be called "entropy". Definition Given a bipartite quantum state \rho^, the entropy of the joint system AB is S(AB)_\rho \ \stackrel\ S(\rho^), and the entropies of the subsystems are S(A)_\rho \ \stack ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entropy Measure
Entropy is a Science, scientific concept, most commonly associated with states of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynamics, where it was first recognized, to the microscopic description of nature in statistical physics, and to the principles of information theory. It has found far-ranging applications in chemistry and physics, in biological systems and their relation to life, in cosmology, economics, sociology, Atmospheric science, weather science, climate change and information systems including the transmission of information in Telecommunications, telecommunication. Entropy is central to the second law of thermodynamics, which states that the entropy of an isolated system left to spontaneous evolution cannot decrease with time. As a result, isolated systems evolve toward thermodynamic equilibrium, where the entropy is highest. A consequence of the second law of thermodynamics is that certain p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Separable State
In quantum mechanics, separable states are multipartite quantum states that can be written as a convex combination of product states. Product states are multipartite quantum states that can be written as a tensor product of states in each space. The physical intuition behind these definitions is that product states have no correlation between the different degrees of freedom, while separable states might have correlations, but all such correlations can be explained as due to a classical random variable, as opposed to being due to entanglement. In the special case of pure states the definition simplifies: a pure state is separable if and only if it is a product state. A state is said to be entangled if it is not separable. In general, determining if a state is separable is not straightforward and the problem is classed as NP-hard. Separability of bipartite systems Consider first composite states with two degrees of freedom, referred to as ''bipartite states''. By a postulate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andreas Winter
Andreas J. Winter (born 14 June 1971, Mühldorf, Germany) is a German mathematician and mathematical physicist at the Universitat Autònoma de Barcelona (UAB) in Spain. He received his Ph.D. in 1999 under Rudolf Ahlswede and Friedrich Götze at the Universität Bielefeld in Germany before moving to the University of Bristol and then to the Centre for Quantum Technologies (CQT) at the National University of Singapore. In 2013 he was appointed ICREA Research Professor at UAB. Winter's research is focused in the field of quantum information theory. Some of his main contributions concern the understanding of quantum communication protocols, the coding theory for quantum channels, and the theory of quantum entanglement. Together with Michał Horodecki and Jonathan Oppenheim, he discovered quantum state-merging and used this primitive to show that quantum information could be negative. Together with Marcin Pawlowski, Tomasz Paterek, Dagomir Kaszlikowski, and Valerio Scarani, he discov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jonathan Oppenheim
Jonathan Oppenheim is a professor of physics at University College London. He is an expert in quantum information theory and quantum gravity. Life Oppenheim obtained a bachelor's degree at the University of Toronto in 1993 and PhD at the University of British Columbia in 2001. His PhD thesis titled Q''uantum Time'', focused on time ordering in quantum mechanics and was supervised by Bill Unruh. In 2004, he was a postdoctoral researcher under Jacob Bekenstein and a Royal Society University Fellow at the University of Cambridge before moving to University College London. In 2005, together with Michał Horodecki and Andreas Winter, Oppenheim discovered quantum state-merging and used this primitive to show that quantum information could be negative. Following on this work, Oppenheim and collaborators have developed a resource theory for thermodynamics on the nano and quantum scale. In 2017, Oppenheim and Lluis Masanes derived the third law of thermodynamics using quantum i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michał Horodecki
Michał Horodecki (born 1973) is a Polish physicist at the University of Gdańsk working in the field of quantum information theory, notable for his work on entanglement theory. He co-discovered the Peres-Horodecki criterion for testing whether a state is entangled, and used it to find bound entanglement together with his brother Paweł Horodecki and father Ryszard Horodecki. He co-discovered with Jonathan Oppenheim, Paweł Horodecki and Karol Horodecki that secret key can be drawn from some bound entangled states. Together with Fernando Brandao he proved that every one-dimensional quantum state with a finite correlation length obeys an area law for entanglement entropy. Together with Jonathan Oppenheim and Andreas Winter, he discovered quantum state-merging and used this primitive to show that quantum information could be negative. 2015 he was awarded the ''Minister of Science and Higher Education Awards'' of the Polish government The government of Poland takes the form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum State
In quantum physics, a quantum state is a mathematical entity that embodies the knowledge of a quantum system. Quantum mechanics specifies the construction, evolution, and measurement of a quantum state. The result is a prediction for the system represented by the state. Knowledge of the quantum state, and the rules for the system's evolution in time, exhausts all that can be known about a quantum system. Quantum states may be defined differently for different kinds of systems or problems. Two broad categories are * wave functions describing quantum systems using position or momentum variables and * the more abstract vector quantum states. Historical, educational, and application-focused problems typically feature wave functions; modern professional physics uses the abstract vector states. In both categories, quantum states divide into pure versus mixed states, or into coherent states and incoherent states. Categories with special properties include stationary states for tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Communication
In quantum information theory, a quantum channel is a communication channel that can transmit quantum information, as well as classical information. An example of quantum information is the general dynamics of a qubit. An example of classical information is a text document transmitted over the Internet. Terminologically, quantum channels are completely positive (CP) trace-preserving maps between spaces of operators. In other words, a quantum channel is just a quantum operation viewed not merely as the reduced dynamics of a system but as a pipeline intended to carry quantum information. (Some authors use the term "quantum operation" to include trace-decreasing maps while reserving "quantum channel" for strictly trace-preserving maps.) Memoryless quantum channel We will assume for the moment that all state spaces of the systems considered, classical or quantum, are finite-dimensional. The memoryless in the section title carries the same meaning as in classical information th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mixed State (physics)
In quantum physics, a quantum state is a mathematical entity that embodies the knowledge of a quantum system. Quantum mechanics specifies the construction, evolution, and measurement of a quantum state. The result is a prediction for the system represented by the state. Knowledge of the quantum state, and the rules for the system's evolution in time, exhausts all that can be known about a quantum system. Quantum states may be defined differently for different kinds of systems or problems. Two broad categories are * wave functions describing quantum systems using position or momentum variables and * the more abstract vector quantum states. Historical, educational, and application-focused problems typically feature wave functions; modern professional physics uses the abstract vector states. In both categories, quantum states divide into pure versus mixed states, or into coherent states and incoherent states. Categories with special properties include stationary states for time in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Review A
''Physical Review A'' (also known as PRA) is a monthly peer-reviewed scientific journal published by the American Physical Society covering atomic, molecular, and optical physics and quantum information. the editor was Jan M. Rost ( Max Planck Institute for the Physics of Complex Systems). History In 1893, the '' Physical Review'' was established at Cornell University. It was taken over by the American Physical Society (formed in 1899) in 1913. In 1970, ''Physical Review'' was subdivided into ''Physical Review A'', ''B'', ''C'', and ''D''. At that time, section ''A'' was subtitled ''Physical Review A: General Physics''. In 1990, a process was started to split this journal into two, resulting in the creation of '' Physical Review E'' in 1993. Hence, in 1993, ''Physical Review A'' changed its statement of scope to ''Atomic, Molecular and Optical Physics.'' In January 2007, the section of ''Physical Review E'' that published papers on classical optics was merged into ''Physical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Information Theory
Quantum information is the information of the state of a quantum system. It is the basic entity of study in quantum information theory, and can be manipulated using quantum information processing techniques. Quantum information refers to both the technical definition in terms of Von Neumann entropy and the general computational term. It is an interdisciplinary field that involves quantum mechanics, computer science, information theory, philosophy and cryptography among other fields. Its study is also relevant to disciplines such as cognitive science, psychology and neuroscience. Its main focus is in extracting information from matter at the microscopic scale. Observation in science is one of the most important ways of acquiring information and measurement is required in order to quantify the observation, making this crucial to the scientific method. In quantum mechanics, due to the uncertainty principle, non-commuting observables cannot be precisely measured simultaneously, as ... [...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. The journal is considered one of the most prestigious in the field of physics. Over a quarter of Physics Nobel Prize-winning papers between 1995 and 2017 were published in it. ''PRL'' is published both online and as a print journal. Its focus is on short articles ("letters") intended for quick publication. The Lead Editor is Hugues Chaté. The Managing Editor is Robert Garisto. History The journal was created in 1958. Samuel Goudsmit, who was then the editor of '' Physical Review'', the American Physical Society's flagship journal, organized and published ''Letters to the Editor of Physical Review'' into a new standalone journal'','' which became ''Physical Review Letters''. It was the first journal intended for the rapid publication of short articles, a format that eventually became popular in many other fiel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chris Adami
Christoph Carl Herbert "Chris" Adami (born August 30, 1962) is a German-American professor of microbiology and molecular genetics, as well as professor of physics and astronomy, at Michigan State University. He is a core faculty member of the Ecology, Evolution, and Behavior (EEB) Program there. Education Adami was born in Brussels, Belgium, and graduated from the European School of Brussels I. He obtained a Diplom in physics from the University of Bonn and an MA and a Ph.D. in theoretical nuclear physics from Stony Brook University in 1991. Adami was a Division Prize Fellow in the lab of Steven E. Koonin at the California Institute of Technology from 1992-1995, and was subsequently on the Caltech faculty as a senior research associate. Career Before joining Michigan State University, he was a professor of Applied Life Sciences at the Keck Graduate Institute in Claremont, California. Adami is best known for his work on Avida, an artificial life simulator used to study evolutiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
