Where does modern Physics take us?

Discussion in 'Chit Chat' started by nitro, Jun 4, 2015.

  1. Let;s be clear, this is almost as rank speculation as the existence of God.

    It's ok to speculated (dream) but chickens come home to roost with the scant evidence.:confused:

    Anything is NOT possible. This notion has very very little evidence and will probably be discredited (as most notions are on the edge of discovery and knowledge)
     
    #41     Nov 28, 2015
  2. nitro

    nitro

    #42     Dec 1, 2015
  3. nitro

    nitro

    Topology is very important in modern Physics

     
    #43     Dec 20, 2015
  4. nitro

    nitro

    #44     Jan 2, 2016
  5. Q

    Quantum entanglement is a physical phenomenon that occurs when pairs or groups of particles are generated or interact in ways such that the quantum state of each particle cannot be described independently — instead, a quantum state may be given for the system as a whole.

    https://en.wikipedia.org/wiki/Quantum_entanglement

    Concept

    Meaning of entanglement


    An entangled system is defined to be one whose quantum state cannot be factored as a product of states of its local constituents (e.g. individual particles). If entangled, one constituent cannot be fully described without considering the other(s). Note that the state of a composite system is always expressible as a sum, or superposition, of products of states of local constituents; it is entangled if this sum necessarily has more than one term.

    Quantum systems can become entangled through various types of interactions. For some ways in which entanglement may be achieved for experimental purposes, see the section below on methods. Entanglement is broken when the entangled particles decohere through interaction with the environment; for example, when a measurement is made.[29]

    As an example of entanglement: a subatomic particle decays into an entangled pair of other particles. The decay events obey the various conservation laws, and as a result, the measurement outcomes of one daughter particle must be highly correlated with the measurement outcomes of the other daughter particle (so that the total momenta, angular momenta, energy, and so forth remains roughly the same before and after this process). For instance, a spin-zero particle could decay into a pair of spin-½ particles. Since the total spin before and after this decay must be zero (conservation of angular momentum), whenever the first particle is measured to be spin up on some axis, the other (when measured on the same axis) is always found to be spin down. (This is called the spin anti-correlated case; and if the prior probabilities for measuring each spin are equal, the pair is said to be in the singlet state.)

    Mystery of time

    There exist physicists who say that time is an emergent phenomenon that is a side effect of quantum entanglement.[40][41] The Wheeler–DeWitt equation that combines general relativity and quantum mechanics – by leaving out time altogether – was introduced in the 1960s and it was taken up again in 1983, when the theorists Don Page and William Wootters made a solution based on the quantum phenomenon of entanglement. Page and Wootters argued that entanglement can be used to measure time.[42]

    In 2013, at the Istituto Nazionale di Ricerca Metrologica (INRIM) in Turin, Italy, Ekaterina Moreva, together with Giorgio Brida, Marco Gramegna, Vittorio Giovannetti, Lorenzo Maccone, and Marco Genovese performed the first experimental test of Page and Wootters' ideas. Their result has been interpreted to confirm that time is an emergent phenomenon for internal observers but absent for external observers of the universe.[42]

    Source for the arrow of time

    Physicist Seth Lloyd says that quantum uncertainty gives rise to entanglement, the putative source of the arrow of time. According to Lloyd; "The arrow of time is an arrow of increasing correlations."[43]

    Non-locality and hidden variables

    There is much confusion about the meaning of entanglement, non-locality and hidden variables and how they relate to each other. As described above, entanglement is an experimentally verified and accepted property of nature, which has critical implications for the interpretations of quantum mechanics. The question becomes, "How can one account for something that was at one point indefinite with regard to its spin (or whatever is in this case the subject of investigation) suddenly becoming definite in that regard even though no physical interaction with the second object occurred, and, if the two objects are sufficiently far separated, could not even have had the time needed for such an interaction to proceed from the first to the second object?"[44] The latter question involves the issue of locality, i.e., whether for a change to occur in something the agent of change has to be in physical contact (at least via some intermediary such as a field force) with the thing that changes. Study of entanglement brings into sharp focus the dilemma between locality and the completeness or lack of completeness of quantum mechanics.

    Bell's theorem and related results rule out a local realistic explanation for quantum mechanics (one which obeys the principle of locality while also ascribing definite values to quantum observables). However, in other interpretations, the experiments that demonstrate the apparent non-locality can also be described in local terms: If each distant observer regards the other as a quantum system, communication between the two must then be treated as a measurement process, and this communication is strictly local.[45] In particular, in the Many-worlds interpretation, the underlying description is fully local.[46] More generally, the question of locality in quantum physics is extraordinarily subtle and sometimes hinges on precisely how it is defined.

    In the media and popular science, quantum non-locality is often portrayed as being equivalent to entanglement. While it is true that a bipartite quantum state must be entangled in order for it to produce non-local correlations, there exist entangled states that do not produce such correlations. A well-known example of this is the Werner state that is entangled for certain values of p_{sym}, but can always be described using local hidden variables.[47] In short, entanglement of a two-party state is necessary but not sufficient for that state to be non-local. Moreover, it was shown that, for arbitrary number of party, there exist states that are genuinely entangled but admits a fully local strategy. It is important to recognize that entanglement is more commonly viewed as an algebraic concept, noted for being a precedent to non-locality as well as to quantum teleportation and to superdense coding, whereas non-locality is defined according to experimental statistics and is much more involved with the foundations and interpretations of quantum mechanics.
    UQ
     
    #45     Jan 3, 2016
  6. nitro

    nitro

    #46     Jan 4, 2016
  7. wildchild

    wildchild

    You cannot prove a hypothesis or theory is correct, you can only disprove it.
     
    #47     Jan 4, 2016
  8. wildchild

    wildchild

     
    #48     Jan 4, 2016
  9. nitro

    nitro

     
    #49     Jun 22, 2016