Then how am I supposed to eliminate my delta brain wave?
isn't the predestination paradox a logical explanation too?
[QUOTE=bobsmit;23625870]Then how am I supposed to eliminate my delta brain wave?[/QUOTE]
Have sex with your mother?
:gonk:
Oh God my mind hurts.
Wait, so now it would be possible for me to go back in time, bone someone, and come back without any really really bad consequences?
[QUOTE=David29;23625188]This.
I don't know why he is being rated dumb because one widely accepted idea is that every action or decision creates a 'split' leading to two (or more) different time-lines branching off from this. So for example, I have a can of cider next to me and I just chose not to take a swig of it. However, if I went back and did drink it, then I would branch off into the alternate time-line.[/QUOTE]
The reason why that isn't right is while the universe is said to branch at a random event, that only happens when there is a truly random event. Someone making a decision is not really a random event.
Think about it like this. Every person is operating on input that they receive. When someone receives the exact same input their decision will never ever change, so no branching occurs when you make a choice, I'm sorry to say.
The brain is a bunch of very complex chemical and electrical interactions, so if everything is perfectly identical it's as predictable as water pouring into a bucket.
some argue there is no random event in the universe, only extremely spontaneous hidden variables
I thought this meant that this time machine gets around the grandfather paradox by simply not allowing you to travel back in time if it means you kill your grandfather.
[QUOTE=Disgruntled;23627592]Wait, so now it would be possible for me to go back in time, bone someone, and come back without any really really bad consequences?[/QUOTE]
Unless you get the clap
[editline]08:49AM[/editline]
[QUOTE=Jabberwocky;23635468]I thought this meant that this time machine gets around the grandfather paradox by simplying not allowing you to travel back in time if it means you kill your grandfather.[/QUOTE]
That's what I though! Hi-five!
[QUOTE=Disfunction;23629411]The reason why that isn't right is while the universe is said to branch at a random event, that only happens when there is a truly random event. Someone making a decision is not really a random event.
Think about it like this. Every person is operating on input that they receive. When someone receives the exact same input their decision will never ever change, so no branching occurs when you make a choice, I'm sorry to say.
The brain is a bunch of very complex chemical and electrical interactions, so if everything is perfectly identical it's as predictable as water pouring into a bucket.[/QUOTE]
[img]http://fishbowl.pastiche.org/archives/pictures/matrix-architect.jpg[/img]
"The problem is choice."
[QUOTE=Disfunction;23629411]The reason why that isn't right is while the universe is said to branch at a random event, that only happens when there is a truly random event. Someone making a decision is not really a random event.
Think about it like this. Every person is operating on input that they receive. When someone receives the exact same input their decision will never ever change, so no branching occurs when you make a choice, I'm sorry to say.
The brain is a bunch of very complex chemical and electrical interactions, so if everything is perfectly identical it's as predictable as water pouring into a bucket.[/QUOTE]
The actual idea is based on the quantum probability. When a particle exists as a probability wave it DOES exist in all states at the same time. This is something that has been proven in the past (I can't remember off the top of my head who it was, someone called something Bell I think).
When decoherence sets in the probability wavefunction collapses and what we call 'reality' is observed. Some interpretations of QM predict that when this happens a new branch of reality is created for each possible outcome. This is the essence of the many worlds interpretation of QM. It relies on the fact that the laws of nature are fundamentally probabilistic, NOT deterministic.
Only if we could travel back to the future.
Chaos theory guys
[QUOTE=Ickylevel;23619904]I knew this. That you can go to the past and kill your father without consequences. Then you go back to the present but you are not in the same dimension you came from (you can never go back to were you came from).[/QUOTE]
...why was this guy rated dumb, this is the commonly held scientific hypothesis that allows shit to happen and not violate causality.
He was right.
[QUOTE=Killuah;23620331]I like how the picture has Ket-Vectors of the wavefunction but is totally useles without explaination.[/quote]
I thought exactly the same. Putting a (scientific) picture into a post withou explaing what it's actually showing is useless.
All I see there is a probably entangled two-particle system in a) since Alice and Bob are generally used as pseudonyms for entangled particles.
[quote=Killuah]
[quote]Postselection, however, makes the solution easy to find. Simply allow the variables to take any value at random and then postselect on the condition that the answer must be true. This automatically disregards any wrong'uns that come up.[/quote]
Explains nothing.[/QUOTE]
It's just badly explained. Actually if you have a state prepared, it can be described as a superposition of different Eigenstates of the Hamiltonian how you know. Now you put that into your system which only allows a certain (yet unknown) combination of those Eigenstates (the "true"-answer). All other propability-amplitudes of the respective Eigenstates which do not fit in are supressed. Now you can measure the remaining propability amplitudes which give in respect to the variables your desired result.
[editline]11:49AM[/editline]
[QUOTE=Socram;23623707]Quantum physics are dumb.
Whoops, can't explain it! Must be another dimension![/QUOTE]
The field of Quantum Physics is wide and you are probably talking about String Hypothesis.
Without QM (which is btw amongst General and Special Relativity the most proven physical theory every) you wouldn't sit infront of your freaking computer.
Could someone dumb this down for us, normal pepole? :v:
[QUOTE=Disfunction;23629411][B]The reason why that isn't right is while the universe is said to branch at a random event, that only happens when there is a truly random event. Someone making a decision is not really a random event.[/B]
Think about it like this. Every person is operating on input that they receive. When someone receives the exact same input their decision will never ever change, so no branching occurs when you make a choice, I'm sorry to say.
The brain is a bunch of very complex chemical and electrical interactions, so if everything is perfectly identical it's as predictable as water pouring into a bucket.[/QUOTE]
No it just branches off to handle every possibility, it doesn't have to be random but the idea is best explained with random experiences, but decisions make more sense anyway.
[QUOTE=ZuXer;23637991]Could someone dumb this down for us, normal pepole? :v:[/QUOTE]
The time machine will only let you back in time if you don't fuck up the future by doing so.
You're allowed to change some stuff as long as other stuff is compensated so that the same future, the one where you came from, is reached. ie. playing around with the values for variables as long as they arrive at the same 'true' answer.
[QUOTE=ZuXer;23637991]Could someone dumb this down for us, normal pepole? :v:[/QUOTE]
Altered pasts must all arrive at the same future.
[QUOTE=Sir Tristan;23620541]I lold
quantum physician ahahahahaha[/QUOTE]
Duh, everyone knows the real title is "Professor in Quantrumatrics" :rolleyes:
[QUOTE=bravehat;23638008]No it just branches off to handle every possibility, it doesn't have to be random but the idea is best explained with random experiences, but decisions make more sense anyway.[/QUOTE]
Many-World Interpretation got replaced by Decoherence and is a useless waste of universes.
So...
Back to the Future was right?...
I don't understand all these crazy words and numbers...
[QUOTE=aVoN;23641618]Many-World Interpretation got replaced by Decoherence and is a useless waste of universes.[/QUOTE]
Wait so what's the basic overview and implications of Decoherence then? I'd read it myself but I have the cold and my mind can't be fucked trying to make sense of shit just now.
[QUOTE=bravehat;23642005]Wait so what's the basic overview and implications of Decoherence then? I'd read it myself but I have the cold and my mind can't be fucked trying to make sense of shit just now.[/QUOTE]
I think in layman's terms its just a that when two particles wave functions collide and are 'decoherent' with each other, the probability wavefunction collapses and reality is observed. In this sense there are no 'many worlds'.
There are a few counters to this, such as these advantages of Many Worlds:
[quote]* MWI removes the observer-dependent role in the quantum measurement process by replacing wavefunction collapse with quantum decoherence. Since the role of the observer lies at the heart of most if not all "quantum paradoxes," this automatically resolves a number of problems; see for example Schrödinger's cat thought-experiment, the EPR paradox, von Neumann's "boundary problem" and even wave-particle duality. Quantum cosmology also becomes intelligible, since there is no need anymore for an observer outside of the universe.
* MWI is realist, deterministic, local theory, akin to classical physics (including the theory of relativity), at the expense of losing counterfactual definiteness. MWI achieves this by removing wavefunction collapse, which is indeterministic and non-local, from the deterministic and local equations of quantum theory.
* MWI (or other, broader multiverse considerations) provides a context for the anthropic principle which may provide an explanation for the fine-tuned universe.
* MWI, being a decoherent formulation, is axiomatically more streamlined than the Copenhagen and other collapse interpretations; and thus favoured under certain interpretations of Ockham's razor.[49] Of course there are other decoherent interpretations that also possess this advantage with respect to the collapse interpretations.[/quote]
[url]http://en.wikipedia.org/wiki/Many-worlds_interpretation[/url]
These are the common objections and misconceptions of the theory:
[quote] * MWI states that there is no special role nor need for precise definition of measurement in MWI, yet uses the word "measurement" repeatedly through out its exposition.
MWI response: "measurements" are treated a subclass of interactions, which induce subject-object correlations in the combined wavefunction. There is nothing special about measurements (they don't trigger any wave function collapse, for example); they are just another unitary time development process. This is why no precise definition of measurement is required in Everett's formulation.
* The many-worlds interpretation is very vague about the ways to determine when splitting happens, and nowadays usually the criterion is that the two branches have decohered. However, present day understanding of decoherence does not allow a completely precise, self contained way to say when the two branches have decohered/"do not interact", and hence many-worlds interpretation remains arbitrary. This is the main objection opponents of this interpretation raise,[citation needed] saying that it is not clear what is precisely meant by branching, and point to the lack of self contained criteria specifying branching.
MWI response: the decoherence or "splitting" or "branching" is complete when the measurement is complete. In Dirac notation a measurement is complete when:
\lang O[i]|O[j]\rang = \delta_{ij}
where O[i] represents the observer having detected the object system in the i-th state. Before the measurement has started the observer states are identical; after the measurement is complete the observer states are orthonormal. Thus a measurement defines the branching process: the branching is as well- or ill- defined as the measurement is. Thus branching is complete when the measurement is complete. Since the role of the observer and measurement per se plays no special role in MWI (measurements are handled as all other interactions are) there is no need for a precise definition of what an observer or a measurement is — just as in Newtonian physics no precise definition of either an observer or a measurement was required or expected. In all circumstances the universal wavefunction is still available to give a complete description of reality.
Also, it is a common misconception to think that branches are completely separate. In Everett's formulation, they may in principle quantum interfere (i.e. "merge" instead of "splitting") with each other in the future, although this requires all "memory" of the earlier branching event to be lost, so no observer ever sees two branches of reality.
* There is circularity in Everett's measurement theory. Under the assumptions made by Everett, there are no 'good observations' as defined by him, and since his analysis of the observational process depends on the latter, it is void of any meaning. The concept of a 'good observation' is the projection postulate in disguise and Everett's analysis simply derives this postulate by having assumed it, without any discussion.[53]
MWI response: Everett's treatment of observations / measurements covers both idealised good measurements and the more general bad or approximate cases. Thus it is legitimate to analyse probability in terms of measurement; no circularity is present.
* Talk of probability in Everett presumes the existence of a preferred basis to identify measurement outcomes for the probabilities to range over. But the existence of a preferred basis can only be established by the process of decoherence, which is itself probabilistic or arbitrary.
MWI response: Everett analysed branching using what we now call the "measurement basis". It is fundamental theorem of quantum theory that nothing measurable or empirical is changed by adopting a different basis. Everett was therefore free to choose whatever basis he liked. The measurement basis was simply the simplest basis in which to analyse the measurement process.
* We cannot be sure that the universe is a quantum multiverse until we have a theory of everything and, in particular, a successful theory of quantum gravity. If the final theory of everything is non-linear with respect to wavefunctions then many-worlds would be invalid.
MWI response: All accepted quantum theories of fundamental physics are linear with respect to the wavefunction. Whilst quantum gravity or string theory may be non-linear in this respect there is no evidence to indicate this at the moment.
* Conservation of energy is grossly violated if at every instant near-infinite amounts of new matter are generated to create the new universes.
MWI response: Conservation of energy is not violated since the energy of each branch has to be weighted by its probability, according to the standard formula for the conservation of energy in quantum theory. This results in the total energy of the multiverse being conserved.
* Occam's Razor rules against a plethora of unobservable universes — Occam would prefer just one universe; i.e. any non-MWI interpretation.
MWI response: Occam's razor actually is a constraint on the complexity of physical theory, not on the number of universes. MWI is a simpler theory since it has fewer postulates. See the "advantages" section.
* Unphysical universes: If a state is a superposition of two states ΨA and ΨB, i.e. Ψ = (aΨA + bΨB), i.e. weighted by coefficients a and b, then if b \ll a, what principle allows a universe with vanishingly small probability b to be instantiated on an equal footing with the much more probable one with probability a? This seems to throw away the information in the probability amplitudes. Such a theory makes little sense.
MWI response: The magnitude of the coefficients provides the weighting that makes the branches or universes "unequal", as Everett and others have shown, leading the emergence of the conventional probabilistic rules.
* Violation of the principle of locality, which contradicts special relativity: MWI splitting is instant and total: this may conflict with relativity, since an alien in the Andromeda galaxy can't know I collapse an electron over here before she collapses hers there: the relativity of simultaneity says we can't say which electron collapsed first — so which one splits off another universe first? This leads to a hopeless muddle with everyone splitting differently. Note: EPR is not a get-out here, as the alien's and my electrons need never have been part of the same quantum, i.e. entangled.
MWI response: the splitting can be regarded as causal, local and relativistic, spreading at, or below, the speed of light (e.g. we are not split by Schrödinger's cat until we look in the box).[61] For spacelike separated splitting you can't say which occurred first — but this is true of all spacelike separated events, simultaneity is not defined for them. Splitting is no exception; many-worlds is a local theory.
[/quote]
Personally I find Many Worlds to be a very romantic idea for the way the universe works, and I really hope its right. But that's just me being optimistic I guess.
[QUOTE=Socram;23623707]Quantum physics are dumb.
[/QUOTE]
Tyrone u crazy?
[QUOTE=bravehat;23638008]No it just branches off to handle every possibility, it doesn't have to be random but the idea is best explained with random experiences, but decisions make more sense anyway.[/QUOTE]
why would it be for every possibility if only one possibility can ever happen
[editline]03:20PM[/editline]
[url]http://www.youtube.com/watch?v=_VxQuPBX1_U[/url]
[QUOTE=bravehat;23638174]Altered pasts must all arrive at the same future.[/QUOTE]
[img]http://voreblog.files.wordpress.com/2009/03/daniel.jpg[/img]
In all due seriousness, this is actually rather fascinating.
Probability drive GO!
[b][i]Theoretical[/i][/b] science. :colbert:
[QUOTE=Paramud;23656390][b][i]Theoretical[/i][/b] science. :colbert:[/QUOTE]
Technically [I]all[/I] science is theoretical. It's just that some aspects of science are much more readily observable and understandable in day to day life, and so are much more easily accepted. As aVon said above, QM is one of the most successful theories ever devised by man. From that viewpoint, id say its less 'theoretical' (taking into account the connotations used behind that word) than pretty much any other theory used today.
Sorry, you need to Log In to post a reply to this thread.
