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The Observer and Locality in the Quantum World

  1. Jul 19, 2007 #1
    In relativity the observer is equipped with clocks and Rulers and uses them to fix the location of events against a four fold grid system. This is supposed to be done in a completely objective manner. But the objectivity is illusionary, for the observer’s awareness of the physical world is created by the very physics he is supposedly observing. His notion of locality within a four dimensional reference grid system is the product of complex interactions of the component parts of his brain and their interactions with the larger world within which he appears to find himself. The result is that his awareness seems to be limited to a sequence of events, and these events appear to flow through the world in a particular direction: from the past to the future.

    Our experience shows us that using clocks and rulers we can pinpoint our perceived events relative to arbitrarily defined fourfold inertial reference grids.

    The observer, his rulers and clocks are all macroscopic objects formed from countless fundamental microscopic objects. Macroscopic objects are created from the integration of these more fundamental objects. The most important feature; essential to the survival of the observer; is that macroscopic objects have locality; they can be pinpointed with great accuracy relative to our reference grids and to the personal awareness of space and time experienced by the observer. It is only natural, therefore to think of the fundamental constituents also possessing locality. But because our own perception of locality is derived from the integrated behaviour of countless fundamental entities it does not necessarily mean the fundamental entities themselves possess unique locality; in the sense the observer experiences and measures the location of macroscopic objects. Nature does not give us a continuous logical process that provides us with the certainty that quantum objects possess locality as experienced by our consciousness and our experience of using clocks and rulers to fix the location of macroscopic objects relative to our reference frames. Our ability to survive and prosper in this world depends on our sense of time and place. Naturally our intuition demands that we think of quantum objects also having locality in our world but our logic now must over rule instinct and we must accept that quantum objects may not have exact locality relative to our inertial reference frames.

    Although we infer that the communication between the physical world and our consciousness is mediated by quantum objects we do not observe the quantum entities themselves we are only allowed to observe the events associated with macroscopic objects. We may use a photomultiplier to detect a quantum interaction; where the effect of a quantum interaction is amplified to give any observable result. We do not know where or when the interaction between a quantum entity belonging to detector and some other quantum entity occurs that initiates the observable effect at the detector. We can only observe the change in the macroscopic detector and it is this macroscopic event that is perceived by the observer. It is the effect on the detector that is observable and it is the macroscopic detection event to which we can assign locality relative to our inertial frame of reference. It is the group behaviour of the quantum objects forming the detector (and ourselves) that allows us to be able to assign locality to the detection event. To the individual quantum entities we are not given opportunity to assign exact locality.

    The fact that microscopic objects group together to form macroscopic objects to which we can assign locality is the basis of classical mechanics. It allows us to assign macroscopic objects certain physical quantities such as position and time momentum, mass, energy etc that can be used in mathematical relationships in order to describe how objects will behave, given certain experimental set-ups and initial conditions.

    However other than our intuition and common sense, derived from our experience of observable macroscopic objects and events there is no reason that the constituent parts of matter should possess locality. Awareness of locality is a singular condition of the observer. Of all the qualities of our perception of the world locality is by far the most important for our survival. It is hardly surprising that our instincts refuse to accept the possibility that quantum entities do not have locality as understood by our commonsense.

    Indeed much of the language of modern physics reflects our desire to express what goes on in terms of our subjective notion of locality. In some experiment we may refer to the position of a “particle” when we are referring to the observable “position” of a macroscopic slit. The slit will modify the outcome of a macroscopic detection event on a screen. We associate the location of this observable event with the “momentum” of the “particle”. We refer to the probability of “finding” a “particle” in certain volume of space, rather than to finding an observable event consequential to some quantum interaction with a detector located in the said volume of space.

    Much of the “philosophy” of modern physics rest on the notion of locality, in particular the notion that electromagnetism is mediated by a photon. The principle reason for the existence of the idea of the photon is to maintain the idea of locality at quantum level. Clearly if quantum entities that constitute matter do not have exactly defined locality then they may interact directly without the need for a carrier particle.

    Understanding how quantum entities relate to locality on our inertial reference frames is possibly one of the greatest challenges in natural philosophy.

    The validity of quantum mechanics and relativity seem beyond dispute so any solution to the problem of quantum locality must be consistent with both these foundations. The group behaviour of the quantum objects forming observable matter must therefore be consistent with the theory of relativity. In quantum mechanics the problem of locality is circumvented by the Born Rule, so that any explanation of quantum locality must explain the efficacy of this device.

    In my opinion it is the existence of the notion of the photon (and other bosons) is the principle obstacle facing natural philosophy in developing a general theory of quantum locality. Since it owes more to our instinct for survival than rational thought.
  2. jcsd
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