Einzelnen Beitrag anzeigen
  #8  
Alt 02.10.16, 13:37
Plankton Plankton ist offline
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Standard AW: Quanten-Kausalität: A verursacht B verursacht A

Zitat:
Zitat von Hawkwind Beitrag anzeigen
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Spekulationen über Spekulationen ... .
Hmmm.... der Thread gehört eigentlich in "Theorien jenseits der Standardphysik". Wenn die Moderation möchte, das wäre nett.
Jedenfalls ist das ein theoretische Betrachtung dieses Gedankenexperiments!
Ich finde eben diesen Ansatz interessant! Man geht davon aus die QM gilt nur lokal und erzeugt dann [auch mit Verschränkung] neuartige Situationen (die global Kausalität verletzen).
Zitat:
Strategy for accomplishing communication task by using processes with definite and indefinite causal order.

(a) There exists a global background time according to which Alice’s actions are strictly before Bob’s. She sends her input a to Bob, who can read
it out at some later time and give his estimate y=a. However, Bob cannot send his bit b to Alice as the system passes through her laboratory at some earlier time. Consequently, she can only make a random guess of Bob’s bit. This results in a probability of success of 3/4 [*2].
(b) If the assumption of a definite order is dropped, it is possible to devise a resource (i.e. a process matrix W) and a strategy that enables
a probability of success (2+√2)/4 > 3/4 [*8](see text).
Mich fasziniert so etwas schon allein aus dem Grund, weil es eine Arbeit ist welche in die Richtung "Raumzeit entsteht aus Quantenmechanik" geht. Gibt zwar hier keine parallelen zur AdS/CFT-Korrespondenz, wenn allerdings wirklich "Raumzeit aus Verschränkung" gemacht ist, dann wären Situationen wie beschrieben hier einleuchtend!

Zitat:
Furthermore, since the conformal space-time metric is a description of the causal relation between space-time points [39, 40], one can expect
that an extension of general relativity to the quantum domain would involve situations where different causal orders could coexist “in superposition”. The formalism we presented may offer a natural route in this direction: based only on the assumption that quantum mechanics is valid locally, it yields causal relations that cannot be understood as arising from a definite, underlying order.
Die Frage die angeschnitten wird liegt wohl nur im Gedankenspiel derart:

Zitat:
This is remarkable, since if Alice and Bob perform their experiments inside laboratories that they believe are isolated from the outside world for the duration of their operations, and if they believe that they are able to freely choose the bits a, b, and b', they will have to conclude that the events in their experiment do not take place in a causal sequence. Indeed, the framework only assumes that the local operations
from the input to the output system of each party are correctly described by quantum mechanics, and it is compatible with any physical situation in which one would have all the reasons to believe that each party’s operations are freely chosen in a closed laboratory.
Interestingly, both the classical bound (2) and the quantum violation (8) match the corresponding numbers in the CHSH-Bell inequality [31], which strongly resembles inequality (2).
However, the physical situations to which these inequalities correspond is very different: Bell inequalities can be violated in space-like separated laboratories, while (8) cannot be achieved neither with space-like nor with time-like separated laboratories. It is an open question whether (8) is the maximal possible violation allowed by quantum mechanics.
Wahrscheinlich findet man das wirklich nur interessant, wenn man von Sachen wie AdS/CFT, VWI, Dekohärenz bereits begeistert ist bzw. von der Hypothese --> Raum und Zeit als Ergebnis von Quantenverschränkungen!
Gruß

BTW: Reine Theorie war auch mal die ART, SRT, QM etc. pp. Experimente folgten erst später.
Mit Zitat antworten