Hallo! Mal wieder was zum Thema.
http://quantumcorrelations.weebly.co...ations_cde.pdf
Den Teil:
Zitat:
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Entanglement can be created by incoherent operations on a system S and an incoherent ancilla A IF AND ONLY IF the initial system state pS has nonzero coherence
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hatten wir ja schon ein bisschen diskutiert!
Quasi so:
Elektron 1 = Superposition / coherence (Spin Up/Down x); System S
wechselwirkt mit
Elektron 2 = im "gemischten Zustand" / inkohärent (Spin Down x); Ancilla A
UND wir haben Verschränkung 1 & 2
was dann bedeutet:
Zitat:
The maximum entanglement E between the system S and the initially incoherent ancilla A created by incoherent operations quantifies the initial
coherence Ce in the system state pS
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Quasi, dass die maximal (erreichbare) Verschränkung anzeigt wie viel Superpostion in Elektron 1 "drin steckt [am Start]".
(
AFAIK)
Was aber hat es eigentlich mit "Discord" auf sich?
Zitat:
The output premeasurement state ~P AB:M is entangled for all choices of the Ub IF AND ONLY IF the initial system state Pab has nonzero
discord (with respect to B)
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was dann bedeutet:
Zitat:
The minimum entanglement E between the system AB and the
apparatus M generated during a local (pre)measurement on subsystem B
quantifies the initial discord De in the system
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***
Bei Wiki heißt es:
https://en.wikipedia.org/wiki/Quantum_discord
Zitat:
In quantum information theory, quantum discord is a measure of nonclassical correlations between two subsystems of a quantum system. It includes correlations that are due to quantum physical effects but do not necessarily involve quantum entanglement.
The notion of quantum discord was introduced by Harold Ollivier and Wojciech H. Zurek[1][2] and, independently by L. Henderson and Vlatko Vedral.[3] Olliver and Zurek referred to it also as a measure of quantumness of correlations.[2] From the work of these two research groups it follows that quantum correlations can be present in certain mixed separable states;[4] In other words, separability alone does not imply the absence of quantum effects. The notion of quantum discord thus goes beyond the distinction which had been made earlier between entangled versus separable (non-entangled) quantum states.
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Wie ist ***das als Beispiel mit Elektronen? Will jemand was dazu sagen? Ein Beispiel?