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Strategies & Market Trends : 2026 TeoTwawKi ... 2032 Darkest Interregnum -- Ignore unavailable to you. Want to Upgrade?

To: TobagoJack who wrote (51291)	6/14/2009 4:51:50 AM
From: energyplay	1 Recommendation Read Replies (1) \| Respond to of 219785

Yes, and God punished Britain for selling opium. He made them boil all their food for a hundred years....

To: TobagoJack who wrote (51291)	6/14/2009 7:31:39 AM
From: dvdw©	Read Replies (2) \| Respond to of 219785

SAAAD Quantum entanglement From Wikipedia, the free encyclopedia (Redirected from Spooky action at a distance) Jump to: navigation, search Quantum mechanics Uncertainty principle Introduction to... Quantum entanglement is a possible property of a quantum mechanical state of a system of two or more objects in which the quantum states of the constituting objects are linked together so that one object can no longer be adequately described without full mention of its counterpart — even though the individual objects may be spatially separated. This interconnection leads to non-classical correlations between observable physical properties of remote systems, often referred to as nonlocal correlations. For example, quantum mechanics holds that observables such as spin are indeterminate until such time as some physical intervention is made to measure the spin of the object in question. In the singlet state of two spins it is equally likely that any given particle will be observed to be spin-up as that it will be spin-down. Measuring any number of particles will result in an unpredictable series of measures that will tend more and more closely to half up and half down. However, if this experiment is done with entangled particles the results are quite different. When two members of an entangled pair are measured, one will always be spin-up and the other will be spin-down.[citation needed] The distance between the two particles is irrelevant. Theories involving 'hidden variables' have been proposed in order to explain this result; these hidden variables account for the spin of each particle, and are determined when the entangled pair is created. It may appear then that the hidden variables must be in communication no matter how far apart the particles are, that the hidden variable describing one particle must be able to change instantly when the other is measured. If the hidden variables stop interacting when they are far apart, the statistics of multiple measurements must obey an inequality (called Bell's inequality), which is, however, violated — both by quantum mechanical theory and in experiments.[citation needed] When pairs of particles are generated by the decay of other particles, naturally or through induced collision, these pairs may be termed "entangled", in that such pairs often necessarily have linked and opposite qualities, i.e. of spin or charge. The assumption that measurement in effect "creates" the state of the measured quality goes back to the arguments of, among others: Schrödinger, and Einstein, Podolsky, and Rosen[citation needed] (see EPR paradox) concerning Heisenberg's uncertainty principle and its relation to observation (see also the Copenhagen interpretation). The analysis of entangled particles by means of Bell's theorem, can lead to an impression of non-locality (that is, that there exists a connection between the members of such a pair that defies both classical and relativistic concepts of space and time). This is reasonable if it is assumed that each particle departs the scene of the pair's creation in an ambiguous state (as per a possible interpretation of Heisenberg). In such case, either dichotomous outcome of a given measurement remains a possibility; only measurement itself would precipitate a distinct value. On the other hand, if each particle departs the scene of its "entangled creation" with properties that would unambiguously determine the value of the quality to be subsequently measured, then a postulated instantaneous transmission of information across space and time would not be required to account for the result. The Bohm interpretation postulates that a guide wave exists connecting what are perceived as individual particles such that the supposed hidden variables are actually the particles themselves existing as functions of that wave. Observation of wavefunction collapse can lead to the impression that measurements performed on one system instantaneously influence other systems entangled with the measured system, even when far apart. Yet another interpretation of this phenomenon is that quantum entanglement does not necessarily enable the transmission of classical information faster than the speed of light because a classical information channel is required to complete the process.[citation needed] Mathematical formulation of... [show]Background Classical mechanics Old quantum theory Interference · Bra-ket notation Hamiltonian [hide]Fundamental concepts Quantum state · Wave function Superposition · Entanglement Measurement · Uncertainty Exclusion · Duality Decoherence · Ehrenfest theorem · Tunneling [show]Experiments Double-slit experiment Davisson–Germer experiment Stern–Gerlach experiment Bell's inequality experiment Popper's experiment Schrödinger's cat Elitzur-Vaidman bomb-tester Quantum eraser [show]Formulations Schrödinger picture Heisenberg picture Interaction picture Matrix mechanics Sum over histories [show]Equations Schrödinger equation Pauli equation Klein–Gordon equation Dirac equation Bohr Theory and Balmer-Rydberg Equation [show]Interpretations Copenhagen · Ensemble Hidden variable theory · Transactional Many-worlds · Consistent histories Relational · Quantum logic · Pondicherry [show]Advanced topics Quantum field theory Quantum gravity Theory of everything [show]Scientists Planck · Einstein · Bohr · Sommerfeld · Bose · Kramers · Heisenberg· Born · Jordan · Pauli · Dirac · de Broglie ·Schrödinger · von Neumann · Wigner · Feynman · Candlin · Bohm · Everett · Bell · Wien This box: view • talk • edit Contents [hide] 1 Background 2 Pure states 3 Ensembles 4 Reduced density matrices 5 Entropy 5.1 Definition 5.2 As a measure of entanglement 6 Applications of entanglement 7 See also 8 References 9 External links