Could the future already exist? The idea of quantum mechanics is that nature is inherently probabilistic. Particles have no hard properties, only likelihoods, until they are observed. However, even though probability waves would still retain a use in statistical prediction, we find that all testable observations, such as those which make computers run and physics work, continue to function if we adopt predeterminism as the principle driving force for reality. In fact, it seems like many big mysteries of QM such as entanglement, dark energy and the double slit experiment make a lot more sense. Why is there such a strong past-present-future time bias? It's entirely possible that human perception of time is the result of evolution and nothing more. Life must collect energy from states when it is readily available to survive, and the laws of thermodynamics state that things become more disorganized over time. Now, organic intelligent life must be able to predict the future, so evolution has given us this time bias of past-present-future. If this is true, time is free to travel both forwards and backwards and there is no reason for Quantum Mechanics to suggest that the future is decided by chance. Thanks to Einstein's theory of relativity, we know that time passes at a different rate depending on the energy state of an observer. For example, an atomic clock on Earth synchronized with an atomic clock on a space rocket will desynchronize over time. The passage of time is not uniform throughout space. Our solar system is moving towards Lamba Herculis at a rate of 45000mph. Therefore, not all regions of space may travel through time with equal impetus. Distant galaxies accelerating away from us may be the difference between energy states of the two systems. What pulls time forwards? The answer is attraction. The future exerts an effect on the present and vice versa. Many such forces have been defined, but there may be more to discover i.e dark energy. Quantum entanglement is defined as the 'spooky action at a distance' one or more particles can exhibit on each other. Changing the spin of one particle will affect the spin of the other, for example. The speeds of these interactions travel faster than light, seemingly breaking the laws of physics. However, according to predeterminism, these particles are not traveling, but being inferred, so the speed of light is not violated. This could be the basis behind FTL communication or FTL teleportation. The spontaneous appearance of antiparticle pairs has long suggested the magical nature of quantum mechanics. However, this has been a red herring. There is nothing magical about a chemical reaction. The antiparticle existed and exerted its effect on the present particle. It did not randomly decide to pop into existence, but already had its part to play ordained since the dawn of creation. Particles move freely backwards and forwards through time as defined by the physical laws of the universe. The double slit experiment shows how light and matter can display characteristics of both waves and particles. In the original experiment, a laser emits photons through a double slit setup onto a photo-receptive plate, resulting in an interference pattern suggesting that light behaves as a wave. However, the light absorbed is always found in discrete bands as individual particles. Furthermore, when a detector is placed at a slit we find that each photon only passes through one slit, functioning like a particle. This phenomenon is known as complementarity - the act of measuring a particle interacts with it such that the original trajectory is destroyed, and the interference pattern disappears. Now consider the experiment from the particle's point of view. It exists on the plate until such time that a force draws it towards the double slit, backwards through time and into the photon emitter. When undisturbed, it can take either pathway through the double slits, owing to the unpredictable movement of microscopic particles. When we try to detect the particle, it already 'knows' that it cannot take one pathway over the other. Of course, the past has equal effect on the future state, so the particle in the future originates from such a point that the intereference pattern does not exist. This represents the fundamental nature of predeterminism.
But do we know what state a bound electron on the surface of the material constituting the double slit will be in when the photon traveling backwards in time interacts with it? I know of no physics that will accomplish this that does not involve estimates of probability. This would mean that the uncertainty principle works independent of the direction of time's arrow, and also that the future is not something that is predetermined. Or, to put it another way, estimates can be made about aspects of the future, but these too are only probabilities.
That's not for us to 'know'. It's for the photon to 'know'. Our body might 'know' such things, but our mind cannot. That's why we have evolved intelligence and the ability to predict things in order to survive.
Not sure this (the part I have bolded) is entirely correct, although it is a commonly used "sound-bite" regarding QE. I'm not sure it's correct because, as I understand it, to change the spin of one particle will render the previously entangled particles to no longer be entangled. The entangled nature of the particles is such that if one is measured as X then the other will have the corresponding position Y (X and Y being according to the nature of their entanglement... e.g. it might be that for an entangled pair X is spin up and Y is spin down etc). But as soon as you alter one of the pairs, that entanglement is broken. So it is not possible to simply alter one of the pairs and see the other alter accordingly. This is not how entanglement works, or at least not how I understand it to work. As such, it is not possible to use QE for FTL communication in this manner, as the "communication" requires comparison of results of the observations of the particles... which can only be done using conventional communication speeds. But I may have this wrong... my understanding isn't what it could be, alas.
You're quite right. To say that changing the spin of one entangled particle can change the other is a very common misconception about entanglement. Probably because the truth - that we can measure one spin to find out what the other spin is - sounds like plain classical correlation to the uninitiated, so it's not "sexy" enough for pop science reporters.
The universe was believed to be deterministic until circa 1890-1920. Quantum Theory, especially the Uncertainty Principle, sounded its death knell. Almost all (if not all) modern physicists believe that probability laws describe all physical interactions. Most agree with the following thought experiment. (not a quote: I like the format)
The way I see it, physicists are making the observation that things seemingly appear randomly and without a pattern, then using this observation to state that the mechanism of time is based on probability laws. Sounds good. The problem is that while the observation implies the statement, it does not prove it. There are other possibilities which work equally well. One simply has to provide insights into how predeterminism would fit current observations to find that this is the case. The result is a space-time in which such dimensions are the properties of energy and inseparable. It makes no sense to ask what came before the big bang as there was no time. The expansion phase is the measurement of attraction given by future states. At least, this would be the logical conclusion if the big bang theory and predeterminism were true.
The problem with this statement is this: to change the spin of a particle, you need to know what it is. To know what the spin of a particle is you have to measure it. To measure the spin of a particle you have to choose some direction for the measurement. To say the spin of an entangled partner is "affected by" the measurement of the first is one (not very good) way to describe the correlations.
This probably belongs in forum 'General Philosophy', not 'Physics and Math'. I see no math here, very little physics, lots of philosophy, and a quick search reveals this is the case. I was holding until this looked like it was heading in a different direction than the other thread on the Double Slit, which has been obliterated for good cause. Looks OK so far. There is exactly ZERO probability that once a photon begins to propagate in a given direction in a vacuum, that it will reverse direction and propagate back the way it came or in another direction, unless it has been absorbed and reemitted from a mirror, or otherwise becomes bound. Even if it did reflect from something, this is not equivalent to time travel in any real sense. For all intents and purposes, the passage of time when energy becomes bound is the same as for the case when it continues to propagate at c in a straight line. Time dilation is infinite by the math associated with relativity.
From DanShawen Post #10 I believe that many (almost all?) physicists familiar with Quantum processes would disagree with your statement. Radioactive decay is one well known phenomenon which is random. Quantum tunneling is another. These processes are surely within the scope of physics.
See for yourself: https://en.wikipedia.org/wiki/Predeterminism Physics/Math/ or philosophy? This thread belongs in philosophy. Quantum theory was the end of "determinism" of any variety. Nuclear decays are no more "random" than a clock is. Their rates can be predicted, and also measured with very sensitive instruments like NEMO-3 for detecting rare events like double beta decay. Perhaps the best example is this one: https://en.wikipedia.org/wiki/Isotopes_of_zirconium "...one very long-lived radioisotope (96Zr), a primordial nuclide that decays via double beta decay with an observed half-life of 2.0×1019 years…" which is 10^10 times the age of the known universe. Long lived isotopes like this one reason is why it is laughable when string theory predicts the decay of protons. When confronted with the fact that it has been experimentally determined that proton decay doesn't happen within many lifetimes of the known universe, they only shrug and say or mumble in their incomprehensible language something to the effect of: "not long enough". For them, it is no stretch to think of time going backward, so perhaps what they mean is something like: "well, if you run time backwards, then the decay of the proton happens in 13.7 billion years. Nonsense.
From DanShawen Post # 12 The above is incorrect: Physicists use the half life to specify the rate of decay for radioactive because it is a probabilistic phenomenon. Note that the half life is the time expected for half of a group of radioactive atoms to decay. If the half life of an atom is one year, half are expected to decay in one year; 3/4 in two years; 7/8 in 3 years; et cetera. The above indicates a probabilistic phenomenon.
"Why is there such a strong past-present-future time bias?" I attribute one reason to a evolved perception that we are experiencing 'now'. We are actually experiencing a few nanoseconds in the past. I refer to this factor as quanta-drag. It is like jet lag in that it makes our perspective shift into trying to guess the future rather than concentrating on the past. This now gives rise to an intuitive perception of a future moment. It also causes people to believe the past is an illusion, yet in reality we are only observers of our past. We look to the ends of the universe only to see the distant past.
That's not what's happening in quantum physics: http://webpages.charter.net/sn9/science/bellstheorem.html
