# Applications of Quantum physics/Quantum Mechanics?



## Creole Neo

an absurd man said:


> Why would classical speeds be an issue? If it can someday transfer bulk bulk matter from point a to point b faster than any other mode of transportation then there will be an obvious incentive to develop the technology.


Frankly all it means is you can transmit qubits alongside c-bits. Nothing interesting or special like transporting classical matter, or transporting c-info or q-info in any means more interesting or swift than classical transmissions. It's the sort of foundational science necessary to maintain a compatible internet for quantum computers, not the kind of thing that pushes us meaningfully closer to the singularity. My bad for not making it clear enough: QT is not nearly as interesting or disappointing as the media's love-hate relationship with it would imply.


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## HAL

@Diophantine @inbi

Actually I'm fairly sure quantum mechanics is somewhat statistical.

Wave functions break down into probabilistic representations of the thing you want to know more about.

With wave functions, you use things on them called operators. For example, if you want to know about the position of a particle in a confined quantum system, you use the position operator. Essentially you perform some operation on the mathematical wave function, which changes the function so it then describes the thing you want to know about.

In the case of using the position operator, you're left with a function that describes the probability of the particle being in a certain place.

This image may or may not help: (EDIT: Didn't realise the image was actually a GIF. Awesome!)










It's the double-slit experiment, the one where light comes through two slits then the waves interact with each other, causing light and dark fringes on the screen.

By mathematically modelling the photons entering the two slits as a quantum physical system, you can use the position operator and will find a wave function that looks like that shown at the top of the image.

The wave function, as a probability function, is saying simply that there is a greater likelihood of photons hitting the screen at the points where the function has a higher value - where there is a higher probability of the photons landing there. So the peaks in the wave function are the light fringes, and the troughs of the wave function are the dark fringes (since the probability approaches zero).

What this is saying is that _statistically_ you can expect the photons to land in those positions. You can't know for sure, but the wave function, as a probability function, describes it in that way.

"It is most probable that the photons will land on the screen in that way, and statistically we can verify this is the case."


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## intjonn

10 Ways Quantum Physics Will Change the World : Discovery Channel




*<<<===========take it frum a koon!*


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## Diophantine

@_HAL_

Of course, QM is pretty darn statistical. Your observables are described by the expectation values (stats!), while the normalization of WF's and uncertainty (std. deviation from stats!) is pretty darn useful. 

I realize my not equals sign must have been heavily misinterpreted. What I meant was that all QM is statistical, but not all statistics is QM. That _biophysical systems are not necessarily quantum systems if they are governed by statistical laws_; or rather, if we interpret them as such.


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## RobynC

Tezcatlipoca said:


> Time Warp: LSU Researcher Shows Possibility of Cloning Quantum Information from the Past


So basically you could violate the heisenberg uncertainty principle so long as you didn't alter the past?

This would effectively allow one to collect information from the past and thus ensure they could never be defeated, correct?


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## Diophantine

@_RobynC_

As far as I know from my QM course and Griffiths, you cannot "violate" the uncertainty principle in QM. That's kind of like talking about the applications of _Newtonian _dynamics and saying something _violates _Newton's second law. Uncertainty principle means that you cannot measure the state of a particle without collapsing it to one of the possible states. For instance, if the information was encoded by up or down spins on magnetic chips, one would measure a spin up or spin down, but not both, on a single electron (unless you get into weird quantum entanglement things, feel free to research it, some people claim it could lead to faster than light information transfer and therefore make this type of stuff possible- Superluminal communication - Wikipedia, the free encyclopedia ). This article is saying that there is no way to copy quantum information (a.k.a. reproduce a state of the system) and not violate the uncertainty principle at the same time. Here's the actual journal article, which talks about wanting to "avoid grandfather-like paradoxes", i.e. violating fundamental quantum mechanics principles. http://www.imsc.res.in/~aqis13/extended/shorttalks/Todd_Brun_48.pdf Specific quote about this: 



> If one views a density operator as a statistical ensemble or as a state of knowledge, then Deutsch already realized that his model still leads to grandfather-like paradoxes... *However, if one considers a density operator to be the fundamental object which characterizes a quantum state, then Deutsch’s model indeed resolves these paradoxes.*


i.e. without breaking quantum mechanics, let's make a conceptual/mathematical formulation where we take continuous measurements of the system and set up an algorithm to copy information. Then _maybe_, _hypothetically_, we could have something that would loop through these states. Theoretically.


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## Tezcatlipoca

RobynC said:


> So basically you could violate the heisenberg uncertainty principle so long as you didn't alter the past?
> 
> This would effectively allow one to collect information from the past and thus ensure they could never be defeated, correct?


No.


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## DemonAbyss10

The transistor wasnt even possible without some of the early theories and such of quantum mechanics. So yes, it does have applications. The fact that quantum computers are now in use proves such.


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## suremarc

DemonAbyss10 said:


> The transistor wasnt even possible without some of the early theories and such of quantum mechanics. So yes, it does have applications. The fact that quantum computers are now in use proves such.


That doesn't mean that transistors necessarily "use" quantum mechanics. The early pioneers of the transistor relied on classical methods to construct it, and that makes sense because QM calculations _usually_ get classical-looking results. Although, to my understanding, the invention of more modern transistors like the field effect transistor were dependent on QM theory. Source

Also, quantum computers have nothing to do with transistors (most of them don't use transistors) and are for all intents and purposes not in use... quantum computing is still very primitive. The largest quantum computers have around 500 qubits, and are not really useful for anything besides scientific experimentation for studying them. And as for what we've achieved with quantum computing.. the largest integer factored through quantum algorithms is 143. But quantum computing does have potential for the future, if we manage to build much larger quantum computers.


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## RobynC

@Tezcatlipoca

Can you clarify by "no"?


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## Tezcatlipoca

It may cause more difficulty doing so than to just leave it at that.


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## RobynC

Give it a shot


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## LibertyPrime

RobynC said:


> @Tezcatlipoca
> 
> Can you clarify by "no"?


Time travel is impossible because time only exists as an abstract mathematical concept through which we measure change. It does not exist as a actual physical thing. In essence there is only the present change. You cannot undo change without change and then you are right back in the present, you never really move forwards or backwards though time, because time has no arrow. From the past into the future direction is not a reality, because we only ever have the present aka you can not un-eat an apple.

As humans however we require the concept of time to make sense of change, the past is memory & records of change, we can not go back in time or forward.

People who talk about time travel nowadays can be considered crackpots tbh...its pseudoscience .



> Locality is the notion that particles can interact only from adjoining positions in space and time. And unitarity holds that the probabilities of all possible outcomes of a quantum mechanical interaction must add up to one. The concepts are the central pillars of quantum field theory in its original form, but in certain situations involving gravity, both break down, suggesting neither is a fundamental aspect of nature.
> 
> In keeping with this idea, the new geometric approach to particle interactions removes locality and unitarity from its starting assumptions. *The amplituhedron is not built out of space-time and probabilities*; *these properties merely arise as consequences of the jewel’s geometry.* *T**he usual picture of space and time, and particles moving around in them, is a construct.*


*
This means space-time is emergent not fundamental.*

Source: http://www.wired.com/2013/12/amplituhedron-jewel-quantum-physics/


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## suremarc

FreeBeer said:


> Time travel is impossible because time only exists as an abstract mathematical concept through which we measure change. It does not exist as a actual physical thing. In essence there is only the present change. You cannot undo change without change and then you are right back in the present, you never really move forwards or backwards though time, because time has no arrow. From the past into the future direction is not a reality, because we only ever have the present aka you can not un-eat an apple.
> 
> As humans however we require the concept of time to make sense of change, the past is memory & records of change, we can not go back in time or forward.
> 
> People who talk about time travel nowadays can be considered crackpots tbh...its pseudoscience .
> 
> 
> *
> This means space-time is emergent not fundamental.*
> 
> Source: Scientists Discover a Jewel at the Heart of Quantum Physics | Science | WIRED


Really, citing Wired? Clearly a credible source. Stop disseminating your bullshit to people on the internet who don't know better. And stop looking for validation in unrelated threads. 

Time travel is no more pseudo-intellectual tomfoolery than the point you're arguing. Quantum mechanics also implies that matter is emergent and not fundamental, but that doesn't mean matter doesn't exist. Matter is a measurable quantity that has well-defined behavior in much of modern physics. It impractical to use quantum mechanics to calculate the trajectory of a trebuchet projectile--it's just not appropriate in that context both because of the heavy, complex calculations involved and because quantum mechanics largely concerns microscopic phenomena. 

I will reiterate what I told you in another thread: the amplituhedron is a simplified alternative for efficient particle collision calculations, and as far as we know, that's it. It is completely disjoint from the macroscopic cosmological model of the universe and provides no leverage in disproving macroscopic phenomena such as the law of entropy--from which we derive our definition of the cosmological arrow of time, and explain why the psychological arrow of time runs in the same direction. 

No theory as of yet has truly reconciled quantum mechanics with macroscopic phenomena including the properties of space-time and the direction of time (2nd law of thermodynamics). A theory of quantum gravity is still far into the future, and it's silly to jump on the prospect simply because Wired or PopSci publishes an article proclaiming such--they're not interested in intellectual discovery, they're interested in grabbing the attention of naive readers like you. 

So while quantum mechanics makes incredibly accurate predictions about nature (and is the basis of modern chemistry, really), it remains a practical theory. Even the world's foremost experts in quantum theory fail to reach consistent conclusions about its implications. 

On a personal note: we're both Seekers (469), and we both search for truth. But be careful about where you draw your convictions from, because many authorities may seek only to facetiously and dishonestly promote controversial worldviews simply for the attention, and in the vast majority of cases they are facilitating false intellectual pursuit. 

And the the vast majority of graduate professors will tell you this: if you think you've understood quantum mechanics, you're wrong. The mathematics involved in high-level QM courses get incredibly complex, and the most hotly contested topics in QM are understood by very few people in the world. It is meaningless to discuss the philosophical implications of quantum theory if you haven't done the math--and in general it's meaningless to talk philosophy without making any connections to reality, because you don't get any valuable perspective from indulging in philosophical fantasy.


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## RobynC

@FreeBeer



> Time travel is impossible because time only exists as an abstract mathematical concept through which we measure change.


Then what causes change? Also why does all the change occur in a specific sequence, not all at once?



> As humans however we require the concept of time to make sense of change, the past is memory & records of change, we can not go back in time or forward.





> *This means space-time is emergent not fundamental.*


Meaning, it's the byproduct of something else, it emerges out of other processes. What are these?


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## LibertyPrime

@suremarc

 why not? I don't get your obsession with authority on the subject, the fact that the past and the future are mental constructs we use to measure change is self evident. You can not really believe that time as we know it is a physical thing that exists outside of consciousness. The observer is a requirement.

o.o well similarly I can argue that ethics does not exist outside of the conscious observer(s). What we deem as right and wrong has no value outside of us. So in essence without us ethics does not exist, indeed ethics does not exist out there as a physical thing. It is emergent from consciousness. A rock is a emergent physical thing, ideas are not physical or palpable, neither is consciousness.

o.o I only believe what makes sense to me, but that doesn't mean its not true even if I don't believe it. I can think the world is flat, while it actually isn't. Absolute objective reality exists outside of myself, I am aware of this.

You can disagree with me and hold a completely different opinion at any time & Robyn can consider both sides. I may be wrong, but this is what I think is actually true in light of the problems between classical physics and quantum theory.

You'd say time exists because we can measure it (because that is the definition), but that is still within the human context of how we try to make sense of what we see. The universe may actually not work like that at all. We require the concept of time, because all of known macroscopic physics would break down without it.

I suggest checking out Julian Barbour








RobynC said:


> FreeBeer
> 
> Then what causes change? Also why does all the change occur in a specific sequence, not all at once?
> 
> 
> 
> [/B]Meaning, it's the byproduct of something else, it emerges out of other processes. What are these?


Quantum experiment shows how time emerges from entanglement


> This is an elegant and powerful idea. It suggests that time is an emergent phenomenon that comes about because of the nature of entanglement. And it exists only for observers inside the universe. Any god-like observer outside sees a static, unchanging universe, just as the Wheeler-DeWitt equations predict.


o.o as I said in another post, we seem carry time with us in our heads.


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## Diophantine

RobynC said:


> @_Tezcatlipoca_
> 
> Can you clarify by "no"?


I am sure it's pretty much what I said, just summed up in one word. No because just no. 










A.k.a. The uncertainty principle is the backbone of QM, if you break it, QM is meaningless.

Secondly, the actual journal said nothing about breaking the uncertainty principle, it actually talked about _keeping the math within the framework of QM_.


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## Tezcatlipoca

Recently a way around uncertainty was discovered for a particular case, however that is only marginally relevant to the original discussion but I thought it should be noted
http://www.nature.com/nphoton/journal/v7/n4/full/nphoton.2013.24.html


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## Diophantine

Tezcatlipoca said:


> Recently a way around uncertainty was discovered for a particular case, however that is only marginally relevant to the original discussion but I thought it should be noted
> http://www.nature.com/nphoton/journal/v7/n4/full/nphoton.2013.24.html


How is that a "way around the uncertainty principle"? Here's the original article: http://arxiv.org/pdf/1206.2618v3.pdf 

What they did was they built up the statistical picture of the system by continuously fitting their results to the Dirac probability distribution to a_ beam of particles_ _they measure many times_. Whereas HUP is talking about a single state. And before you say you can apply what they found for continuous stream of photons to just one, please see this: http://en.wikipedia.org/wiki/No-cloning_theorem

They have a good idea of one part of the system while having a bad idea of the other part, falling within the limits of HUP. They characterized their system with probabilities which is what QM has been doing all along. Nowhere do I see them "circumventing" the uncertainty principle or anything like that. 

Classic example of headline blowing things out of proportion, as is typical with QM research being hyped. And Heisenberg is still as relevant now as it was in the 1930's.


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## RobynC

@FreeBeer



> Quantum experiment shows how time emerges from entanglement


*I. Entanglement*

.....1. How does measuring the polarization of something create entanglement? 
.....2. How does one break entanglement?

*II. Time/Polarization of Entangled Particles*
So effectively the polarization of the 1st and 2nd photon entangled produces a measure of time?

*III. Experiments / Future Trends*

.....1. The first experiment seems to be based around the idea of using entangled particles to create a "small universe" with the "clock" either independent or dependent on this to measure the passage of time

.....2. Looking at what I read, it would appear they wish to create a larger scale experiment, what I'm interested about is what it entails? I'm curious if they're planning on making some kind of gigantic universe simulation? That strikes me as potentially ethically problematic if you end up with a sufficiently complicated system (if you've ever seen the game "Life", even relatively small rules can produce rather complicated results that mimic organic systems...)

*IV. Other Questions/Notes* 
I'm curious as to this experiment yielding a result similar to a holographic universe theory, whereby basically a 3D image is the result of one or more 2D images. In this case, the polarization of several entangled particles ends up producing the phenomenon of time.


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## FearAndTrembling

I remember Wilczek said you have to let one thing "float":

According to the original uncertainty principle, to pin down a position accurately we must live with a large uncertainty in momentum. An addendum to Heisenberg’s original uncertainty principle is required by the theory of relativity, which relates space to time and momentum to energy. This additional principle says that to pin down a time accurately we must live with a large uncertainty in energy. Combining the two principles, we discover that to take high-resolution, short-time snapshots, we must let momentum and energy float.

Ironically, the central technique of the Friedman-Kendall- Taylor experiments, as we mentioned, was precisely to concentrate on measuring the energy and momentum. But there’s no contradiction. On the contrary, their technique is a wonderful example of Heisenberg’s uncertainty principle cleverly harnessed to give certainty. The point is that to get a sharply resolved space-time image you can—and must—combine results from many collisions with different amounts of energy and momentum going into the proton. Then, in effect, image processing runs the uncertainty principle backwards. You orchestrate a carefully designed sampling of results at different energies and momenta to extract accurate positions and times.


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## Tezcatlipoca

Diophantine said:


> How is that a "way around the uncertainty principle"? Here's the original article: http://arxiv.org/pdf/1206.2618v3.pdf
> 
> What they did was they built up the statistical picture of the system by continuously fitting their results to the Dirac probability distribution to a_ beam of particles_ _they measure many times_. Whereas HUP is talking about a single state. And before you say you can apply what they found for continuous stream of photons to just one, please see this: No-cloning theorem - Wikipedia, the free encyclopedia
> 
> They have a good idea of one part of the system while having a bad idea of the other part, falling within the limits of HUP. They characterized their system with probabilities which is what QM has been doing all along. Nowhere do I see them "circumventing" the uncertainty principle or anything like that.
> 
> Classic example of headline blowing things out of proportion, as is typical with QM research being hyped. And Heisenberg is still as relevant now as it was in the 1930's.


From your link:

Weakmeasurementsoccurintheoppositeregime,wherethecouplingis muchlessthanthepointerwidthδw.Inthiscase,theeigenstatesofˆAare notresolvedbythepointer,sothewavefunctiondoesnotcollapse.Therefore, asubsequentmeasurementperformedonthequantumstatecanbeusedto extractfurtherinformation.Ifthesubsequentmeasurementisstrong,suchthat theeigenstatesareresolved,wecanchoosetoconsideronlythestatisticsof oneparticularoutcome;thisiscalledpost-selectionandthechosenoutcomeof interestisthepost-selectedstate.


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## LibertyPrime

RobynC said:


> @<span class="highlight"><i><a href="http://personalitycafe.com/member.php?u=16518" target="_blank">FreeBeer</a></i></span>
> 
> *I. Entanglement*
> 
> .....1. How does measuring the polarization of something create entanglement?
> .....2. How does one break entanglement?
> 
> *II. Time/Polarization of Entangled Particles*
> So effectively the polarization of the 1st and 2nd photon entangled produces a measure of time?









> *III. Experiments / Future Trends*
> 
> .....1. The first experiment seems to be based around the idea of using entangled particles to create a "small universe" with the "clock" either independent or dependent on this to measure the passage of time
> 
> .....2. Looking at what I read, it would appear they wish to create a larger scale experiment, what I'm interested about is what it entails? * I'm curious if they're planning on making some kind of gigantic universe simulation? That strikes me as potentially ethically problematic if you end up with a sufficiently complicated system (if you've ever seen the game "Life", even relatively small rules can produce rather complicated results that mimic organic systems...)*


The universe we live in is already this such a simulation, no need to create one, just figure out a way to test it clearly.



> *IV. Other Questions/Notes*
> I'm curious as to this experiment yielding a result similar to a holographic universe theory, whereby basically a 3D image is the result of one or more 2D images. In this case, the polarization of several entangled particles ends up producing the phenomenon of time.


I don't know. I'm not a physicist.


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## Diophantine

Tezcatlipoca said:


> From your link:
> 
> Weakmeasurementsoccurintheoppositeregime,wherethecouplingis muchlessthanthepointerwidthδw.Inthiscase,theeigenstatesofˆAare notresolvedbythepointer,sothewavefunctiondoesnotcollapse.Therefore, asubsequentmeasurementperformedonthequantumstatecanbeusedto extractfurtherinformation.Ifthesubsequentmeasurementisstrong,suchthat theeigenstatesareresolved,wecanchoosetoconsideronlythestatisticsof oneparticularoutcome;thisiscalledpost-selectionandthechosenoutcomeof interestisthepost-selectedstate.


And? Again, this is based on a continuous measurement of a beam of photons rather than the state of one particular photon. The uncertainty principle still stands. If you don't understand why, please look into the uncertainty principle more as well as read the paper closely.


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## ThatOneWeirdGuy

HAL said:


> I agree with quantum computing. I know fuck all about it, but it's such a hotly discussed subject that it is surely on its way. The pinnacle will be when computers reach their maximum physically possible speed. This will presumably be done only with quantum mechanics.


As far as I understand, they're relatively quite slow, but they can process ridiculous amounts of information at a time. Theoretically.

Which really doesn't make much sense to me, tbh, considering speed is how much information can be processed in a given amount of time. Just what I was told, maybe someone else knows what he was talking about.


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## suremarc

> why not? I don't get your obsession with authority on the subject, the fact that the past and the future are mental constructs we use to measure change is self evident. You can not really believe that time as we know it is a physical thing that exists outside of consciousness. The observer is a requirement.


Again, not necessarily true depending on your interpretation of quantum mechanics. Most physicists will disagree with the statement that consciousness is a necessary component (in the QM conference poll I cited, only 6% of 33 experts held that view). The observer doesn't exist outside of reality as something supernatural--it's not the act of conscious measurement, but the act of _interfering_ with quantum systems that causes the wave function collapse. 



> o.o well similarly I can argue that ethics does not exist outside of the conscious observer(s). What we deem as right and wrong has no value outside of us. So in essence without us ethics does not exist, indeed ethics does not exist out there as a physical thing. It is emergent from consciousness. A rock is a emergent physical thing, ideas are not physical or palpable, neither is consciousness.


Ethics isn't related to science in the slightest because it's not quantifiable. Time, however, is. This is philosophical fantasy. 



> o.o I only believe what makes sense to me, but that doesn't mean its not true even if I don't believe it. I can think the world is flat, while it actually isn't. Absolute objective reality exists outside of myself, I am aware of this.
> 
> You can disagree with me and hold a completely different opinion at any time & Robyn can consider both sides. I may be wrong, but this is what I think is actually true in light of the problems between classical physics and quantum theory.


And you shouldn't because it _is_ wrong, and you shouldn't be spreading false beliefs to people uneducated in theoretical physics. 



> You'd say time exists because we can measure it (because that is the definition), but that is still within the human context of how we try to make sense of what we see. The universe may actually not work like that at all. We require the concept of time, because all of known macroscopic physics would break down without it.


There's no scientific basis for that claim--it's pure philosophical silliness. Until a). you get your M.D. in quantum physics, or b). a model quantum gravity without space-time is successfully published and accepted, stop making unsupported assertions. 

As for Barbour, don't believe everything you read.
EDIT: My mistake, _The Secret_ isn't by Barbour. I was confusing it with _The End Of Time_. But you should still read that link.


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## Diophantine

suremarc said:


> There's no scientific basis for that claim--it's pure philosophical silliness. Until a). you get your M.D. in quantum physics, or b). a model quantum gravity without space-time is successfully published and accepted, stop making unsupported assertions.


M.D. in quantum mechanics? Is that like for a doctor who specializes in the psychiatry of physicists? :tongue:


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## suremarc

Diophantine said:


> M.D. in quantum mechanics? Is that like for a doctor who specializes in the psychiatry of physicists? :tongue:


Hey, I'm just a lowly 16 year old. Don't expect me to know shit about college :sad:


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## Tezcatlipoca

Diophantine said:


> And? Again, this is based on a continuous measurement of a beam of photons rather than the state of one particular photon. The uncertainty principle still stands. If you don't understand why, please look into the uncertainty principle more as well as read the paper closely.


Normally it would not be possible to get this information about the polarization states through a single measurement which is what the article was referring to. You are using "get around" to signify a different operation than that to which the author was referring.


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## RobynC

1. So basically if you duplicate a photon into four, then hit four separate electrons with them, all the photons which are entangled effectively entangle them by causing them to all behave the same? 

2. How is the universe a simulation? I've heard the simulation argument, but unless you mean the holographic theory of the universe (which is what I described), I'm not sure if one can verify something like this (or refute it truthfully)

3. You know how you can take several two-dimensional images: (Side, top, front, back) and combine them into a 3D image?


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## PaladinX




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## suremarc

This proposition bugs me: 


> *That strikes me as potentially ethically problematic if you end up with a sufficiently complicated system (if you've ever seen the game "Life", even relatively small rules can produce rather complicated results that mimic organic systems...)*


The first thing to note is that the system in which Conway's game of life resides in is very simple. It's a grid of cells with only two possible states (dead or alive). CGL mimics _life_ in the sense that the patterns formed in it are unpredictable and capable of exhibiting great complexity. But even its most elaborate structures created come nowhere near close to the complexity of organic systems--really, the gap is like that of Heaven and Earth. 

The manner in which Conway's game of life represents information, intrinsically, is extremely limited. Even simpler systems built in CGL appear relatively complex (for example, a universal Turing machine). Further so, the conditions for the emergence of conscious (or even complex) lifeforms depend on very specific criteria--a fine-tuned universe. Here's a nice graphic on that: 










The point being, any simulation of a universe potentially inhabited by conscious lifeforms would have to be both _extremely_ complex and hold _massive_ amounts of information, with the added requirement of being specially designed so that complex and conscious lifeforms are even capable of emerging. Plus, if we hope to study such a system, the computer would need to have insane computing power to handle a sufficient amount of information. To put this in more material terms: *we'd need more 10^100 qubits to simulate our own universe. *Source

Even supposing that the first signs of life appeared in our universe 2-3 million years after the Big Bang, the extended length of time preceding such an event would necessitate that we set our system clock at, say, 1 day per second, to reach that point within 35 years. That's not realistic by any standard.


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## Creole Neo

I'd agree, suremarc, that the machinery required to simulate something on the order of our universe would be truly massive. You might be interested, though, in a slight adjustment of Conway's rules to a continuous floating-point ruleset:


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## Diophantine

Tezcatlipoca said:


> *Normally it would not be possible to get this information about the polarization states through a single measurement which is what the article was referring to.* You are using "get around" to signify a different operation than that to which the author was referring.


Sorry but even with that one is still not getting around HUP. Why? Because the measurement they used is a weak measurement - no wavefunction collapse occurs. You actually don't know 100% of the information about the state, but you come pretty darn close. The uncertainty that remains is due to HUP.  Here's some reading about why weak measurement doesn't contradict, and in fact goes hand in hand with, the HUP. Introduction to Weak Measurements and Weak Values | Tamir | Quanta

Weak measurement of polarization has been done in 1991 and in years after that. Nothing really new about this article except its tabloid headline and possible applications to qubits, etc. 

To quote the article:



> An important result is that a single weak value completely determines the wavefunction of a qubit (see Supplementary Note 2). *For a single photon, the weak measurement has very large uncertainty*; thus*, the above procedure must be repeated on many photons*, or equivalently on a classical light beam, to establish the weak value with a high degree of condence.


Do you see now that the HUP is not violated in any way? A qubit is actually a two-state system (aka the two polarization states) and one couples the polarization value to a measurement device. The single weak value is not really a "single measurement". A single weak value is the result of weak measurement.

Here's a study using the same type of measurement in 2011. Tabloids must have missed their chance to hype up this one, a pity. Science Magazine: Observing the average trajectories of single photons

Note about photon entanglement: I don't think it is fair to discuss it without being familiar with the math and the terminology on this page http://en.wikipedia.org/wiki/Photon_entanglement .


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## John Coltrane

TheIsrafil said:


> I've been watching a bit on Quantum Physics and I find myself wondering, "what is the absolute pinnacle of possibility for this amazing science?" So, I'd like to hear your ideas on this.


Quantum computers! Essentially using the phenomenon of superposition to carry out certain computations in a different way to classical computation & in a few cases incredibly efficiently. Take Peter Shor's use of a quantum computer to calculate Fast Fourier Transforms very rapidly as an example. FFTS have a symmetry that allows them to be split up and carried out in parallel in a manner ideally suited to a quantum computer. A rapid FFT can be used to solve problems like the discrete logarithim problem and the factorization of large integers. The latter can then be used to break a public-key cryptosystem.


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## suremarc

Creole Neo said:


> I'd agree, suremarc, that the machinery required to simulate something on the order of our universe would be truly massive. You might be interested, though, in a slight adjustment of Conway's rules to a continuous floating-point ruleset:


That's fascinating! Although the information density is probably much higher (at least 8 bits per float), it would seem that that system has much more flexibility with the added degrees of freedom. It also has the added bonus of looking cool 

I'm no engineer, but I may try and toy around with the program and see if I can build something interesting..


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## Tezcatlipoca

@Diophantine: I understood it. I was saying you were being overly technical for the purposes of RobynC's query. It is enough to know the uncertainty is reduced significantly. The reason I kept my initial answer so succinct was to avoid these sorts of miscommunications. Thank you for the articles.


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## RobynC

@suremarc

Reply: 46

1. Cosnciousness isn't really a necessary component of QM; in fact the "observer" is merely an interactor.

2. I don't know how people ever came to believe Science/Ethics are interconnected

Reply: 52

1. The point was simple rules can give rise to complicated systems. A sufficient level of complexity could possibly cross the line.

2. Firstly: Our universe has 10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 Q-bits in it?

Secondly: If a simulated universe was created, presumably the "outside" universe would have more Q-Bits available

Thirdly: If a simulated universe existed: It could theoretically be much older than the simulated one.


@Creole Neo

What's a continuous floating point?


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## Creole Neo

RobynC said:


> @Creole Neo
> 
> What's a continuous floating point?


Continuous and floating point are separate adjectives applied to the new ruleset. Floating point as opposed to integer, and continuous meaning a continuous count of stuff within a certain radius of the point being measured as opposed to a discrete grid counting only adjacent cells.


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## RobynC

@Creole Neo

1. What's a ruleset?

2. What is the point being measured? Could you provide a hypothetical example

3. Could you explain this in a simple way that could be provided to a person who is not a computer science expert


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