Search found 561 matches

by Tchebu
Fri May 31, 2013 3:07 pm UTC
Forum: Science
Topic: Is Quantum Mechanics REALLY "Unintuitive?"
Replies: 32
Views: 10798

Re: Is Quantum Mechanics REALLY "Unintuitive?"

It's an unscientific prejudice of mine, but I think QM at the present time is not just incomplete, but incomplete in a way that is 'wrong'. As an analogy, I'd say it's still at the Lamarkian* stage of rightness, and we're still waiting for Darwin... I'd say QM is just as complete as classical mecha...
by Tchebu
Fri May 31, 2013 12:57 am UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2958
Views: 720674

Re: FTL Communication Breaking Causality?

This doesn't seem so bad just yet, because this backwards in time communication still happens between spacelike separated events, however, suppose that Bob has another ansible which can send an instantaneous (in the S2 frame) signal to a bomb sitting next to Alice and he triggers it immediately aft...
by Tchebu
Thu May 30, 2013 9:45 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2958
Views: 720674

Re: FTL Communication Breaking Causality?

Consider the ladder paradox as described in your link with the ladder moving toward the right. Include a third reference frame which is a frame that's moving with respect to the barn with the same speed as the ladder but in the opposite direction. Let's call the barn's reference frame S0, the ladder...
by Tchebu
Thu May 30, 2013 12:44 am UTC
Forum: Science
Topic: Question About Entanglement
Replies: 12
Views: 5912

Re: Question About Entanglement

Just to reiterate what's already been said, but perhaps more explicitly, the problem is that the spins along different directions aren't independent. Once you've said "spin up along z" you've already specified as much as you can about the other directions, because |+z> = |+x> + |-x> = -i(|...
by Tchebu
Mon May 27, 2013 2:57 pm UTC
Forum: Science
Topic: metric expansion of space (question)
Replies: 2
Views: 4210

Re: metric expansion of space (question)

In GR gravity IS a distortion of the metric. The metric is to mass (or more precisely the stress-energy tensor) what the electric field is to charge. So while your scenario is possible (and in fact happens all the time) with electromagnetic forces overcoming the expansion of space, in the case of gr...
by Tchebu
Sat May 25, 2013 2:29 am UTC
Forum: Science
Topic: Likelihood of existence of alternate universes?
Replies: 78
Views: 17153

Re: Likelihood of existence of alternate universes?

The interpretation that is often bandied about is that a mixed state will have "separate worlds" until it is "observed". At which point people get very excited about what "observed" means. My understanding is that "observed" really just means "interacts ...
by Tchebu
Fri May 24, 2013 12:55 am UTC
Forum: Mathematics
Topic: n-dimension rotation: Data rotation
Replies: 4
Views: 2220

Re: n-dimension rotation: Data rotation

The orthogonal group seems like the thing you're looking for.
by Tchebu
Wed May 22, 2013 3:40 am UTC
Forum: Science
Topic: [Physics] Adding forces
Replies: 22
Views: 8660

Re: [Physics] Adding forces

What I want is, like: + If forces A and B are in the exact same direction, the larger magnitude will be taken + If forces A and B have directly opposite directions, then the result is (A + B) I suspect that the reason you want the first feature is because of the everyday intuition that if someone s...
by Tchebu
Tue May 21, 2013 12:37 am UTC
Forum: Science
Topic: Question regarding the speed of light
Replies: 12
Views: 4800

Re: Question regarding the speed of light

Similarly, saying that c defines our units of distance, so c must be constant, is begging the question; we define the units that way because c is constant. The point is that the only physically relevant constants that actually change physical processes instead of just rescaling units have to be dim...
by Tchebu
Tue May 14, 2013 4:26 pm UTC
Forum: Science
Topic: Evolution question - how does complexity arise?
Replies: 201
Views: 28565

Re: Evolution question - how does complexity arise?

I believe Tchebu wasn't advocating that mobility equals complexity. S/He was just pointing out what is usually perceived as a defining characteristic of complexity. I also think s/he meant vertebrates, and not animals, in his/hers comparison. Yes, basically this (oh and I'm male, PolakoVoador). And...
by Tchebu
Tue May 14, 2013 1:30 am UTC
Forum: Science
Topic: Evolution question - how does complexity arise?
Replies: 201
Views: 28565

Re: Evolution question - how does complexity arise?

but if you break it down, what does people (stereo)typically make happy? wife/husband, kids, .... ... friends, hobbies, fulfilling careers, creative endeavors, listening to music, discussing the mysteries of nature on the xkcd science forum, watching cat videos on youtube... And, awesomely enough, ...
by Tchebu
Mon May 13, 2013 9:24 pm UTC
Forum: Science
Topic: Evolution question - how does complexity arise?
Replies: 201
Views: 28565

Re: Evolution question - how does complexity arise?

No, it is pretty true. If you want to be depressed about the futility of it all, take an Animal Behavior class, and you'll see how ALL behavior, from human to star fish, can be boiled down to 'females found it sexy', or 'increases the chances of making it to the point where females might find somet...
by Tchebu
Mon May 13, 2013 8:49 pm UTC
Forum: Science
Topic: Evolution question - how does complexity arise?
Replies: 201
Views: 28565

Re: Evolution question - how does complexity arise?

So do plants - it isn't via magic that they keep their leaves orientated towards the sun... Certainly, but only if you stare at them carefully enough. That's my point, that the perceived complexity of something actually depends on the level of detail at which you study it. I don't think we actually...
by Tchebu
Mon May 13, 2013 5:07 pm UTC
Forum: Science
Topic: Evolution question - how does complexity arise?
Replies: 201
Views: 28565

Re: Evolution question - how does complexity arise?

I think it's also important to distinguish between the different scales or levels on which we evaluate complexity if we're going to come up with a proper definition. At least part of the reason we intuitively think mammals are more complex than tomatoes is because mammals have visible moving parts a...
by Tchebu
Sun May 12, 2013 10:36 pm UTC
Forum: Science
Topic: Evolution question - how does complexity arise?
Replies: 201
Views: 28565

Re: Evolution question - how does complexity arise?

But "more complex" isn't actually "best". As I said, the best way to dominate the biosphere is to be a fungus or something... But if you're not a fungus you can still do okay enough to make viable offspring, you'll just never make as many as a fungus would, neither in numbers nor...
by Tchebu
Sun May 12, 2013 9:23 pm UTC
Forum: Science
Topic: Evolution question - how does complexity arise?
Replies: 201
Views: 28565

Re: Evolution question - how does complexity arise?

Complexity in the environment doesn't require complexity in the adaptations to it. The best way to live is pretty much "eat a lot and reproduce quickly" as evidenced by the vast dominance of primitive single-celled organisms. Doesn't matter how complex the environment is, if you can make b...
by Tchebu
Sat May 04, 2013 5:20 pm UTC
Forum: Science
Topic: Can light go on forever?
Replies: 71
Views: 18221

Re: Can light go on forever?

Just here to chip in that it is an interesting question and that everyone here is comparing it to light that we have observed, and thus did not travel in a straight line never being stopped. Apples and carrots. Because I share your inclinations on this fine day, I'd like to push your point further....
by Tchebu
Mon Apr 29, 2013 2:29 pm UTC
Forum: Science
Topic: Can light go on forever?
Replies: 71
Views: 18221

Re: Can light go on forever?

It goes on forever... pretty much like any other object that doesn't interact with other stuff...
by Tchebu
Mon Apr 22, 2013 4:08 pm UTC
Forum: Science
Topic: Question about Information
Replies: 21
Views: 1981

Re: Question about Information

This new example isn't any different from the first one. The guy on the outside fires a positron and an electron causing the guy inside to see two photons. This is the tricky statement. The inside guy becomes a superposition of states in which he saw the various outcomes of an electron-positron coll...
by Tchebu
Mon Apr 22, 2013 2:29 pm UTC
Forum: Science
Topic: An Intuition Regarding Strings
Replies: 16
Views: 3250

Re: An Intuition Regarding Strings

You're probably right in that sufficiently high frequency photons require quantum gravity to treat properly, but the point is that whatever the answer is, it's not "it will make a black hole so there's a frequency cutoff" because black holes spacetimes are topologically different from non-...
by Tchebu
Mon Apr 22, 2013 1:47 pm UTC
Forum: Science
Topic: Question about Information
Replies: 21
Views: 1981

Re: Question about Information

I left issues of quantum observation out of the considerations because it essentially amounts to someone passing by and stirring everything without us keeping track of it, in which case of course we'll lose track of things... If you wish to say that the final state of my collision is exactly two pho...
by Tchebu
Mon Apr 22, 2013 12:42 am UTC
Forum: Science
Topic: Question about Information
Replies: 21
Views: 1981

Re: Question about Information

But no natural process replicates the mathematical structure of addition of real numbers without any additional (punintended) details. In principle some precise measurements of the buckets' energy and momentum as well as anything they may have touched in the process can let me figure out which item ...
by Tchebu
Sun Apr 21, 2013 4:30 am UTC
Forum: Science
Topic: Question about Information
Replies: 21
Views: 1981

Re: Question about Information

The point is that specific states have a unique time evolution into both future and past. You can still quantify the amount of classical uncertainty you have due to measurement error by evolving a neighborhood of that state toward the past. From there you can make your measurements arbitrarily preci...
by Tchebu
Wed Mar 27, 2013 12:00 am UTC
Forum: Science
Topic: An Intuition Regarding Strings
Replies: 16
Views: 3250

Re: An Intuition Regarding Strings

Myea, I'm being stupid... never mind.
by Tchebu
Mon Mar 25, 2013 6:48 pm UTC
Forum: Science
Topic: An Intuition Regarding Strings
Replies: 16
Views: 3250

Re: An Intuition Regarding Strings

Well there's always the Planck length. At that point the wavelength becomes smaller than the schwarzschild radius corresponding to the photon's energy.
by Tchebu
Mon Mar 25, 2013 4:08 pm UTC
Forum: Science
Topic: Best proofs of evolution
Replies: 392
Views: 54665

Re: Best proofs of evolution

Thanks, so it's down to the "goals"? How is survival of information in the system we call "evolution", different than survival of information in the system we call a brain/person/individual (either animal or human here)? The thing is, intelligence isn't a clear cut thing, it's m...
by Tchebu
Sun Mar 24, 2013 10:29 pm UTC
Forum: Science
Topic: Best proofs of evolution
Replies: 392
Views: 54665

Re: Best proofs of evolution

So, what in the system of life (including anything else in the universe), is doing the selecting here? If it's "survival", we still need a mechanism that "prefers" survival of a specific, right? Things die. If you die before you reproduce, the percentage of the population that y...
by Tchebu
Sun Mar 24, 2013 5:05 pm UTC
Forum: Science
Topic: Best proofs of evolution
Replies: 392
Views: 54665

Re: Best proofs of evolution

The engineers aren't the ones doing the selection. The algorithm does it based on the fitness function. Notice that if you start with only the first and the 3rd axiom, without a fitness function and removal of those who don't fit it, you'll still have organisms that dominate the percentage of the po...
by Tchebu
Tue Mar 19, 2013 6:32 pm UTC
Forum: Science
Topic: Quantum Physics Interpretation
Replies: 44
Views: 7248

Re: Quantum Physics Interpretation

There are direct mappings between the states and the wavefunction. Definitions surrounding density matrices have direct implications for what the wavefunction 'means'. Yes, and I don't see how claiming that density matrices correspond to probability distributions on certain bases of my hilbert spac...
by Tchebu
Tue Mar 19, 2013 2:08 am UTC
Forum: Science
Topic: Quantum Physics Interpretation
Replies: 44
Views: 7248

Re: Quantum Physics Interpretation

Its basically the same thing, if you take the frequentist definition of probability. Its still the case that probability distributions are features of multiple trials, not single trials. Well I think that's at least part of the point of MWI is that it becomes a feature of a single trial, but tells ...
by Tchebu
Tue Mar 19, 2013 12:57 am UTC
Forum: Science
Topic: Quantum Physics Interpretation
Replies: 44
Views: 7248

Re: Quantum Physics Interpretation

We COULD (well, maybe, its actually a bit tricky to stay consistent with quantum mechanics. Mike Weissman at UIUC has a nice attempt but it requires modifying the Schroedinger equation) just modify the concept of the classical probability ensemble to insist on multiple outcomes (roll a single die, ...
by Tchebu
Sun Mar 17, 2013 5:31 pm UTC
Forum: Science
Topic: Quantum Physics Interpretation
Replies: 44
Views: 7248

Re: Quantum Physics Interpretation

Fair enough, I didn't realize the term was that specific. Thanks for the chance to flesh out my thoughts better.
by Tchebu
Sun Mar 17, 2013 4:01 pm UTC
Forum: Science
Topic: Quantum Physics Interpretation
Replies: 44
Views: 7248

Re: Quantum Physics Interpretation

Fair enough, I understand the objection now and it's a fair one. I would point out thought that when we "measure numbers", we're really making statements like "I saw the light on my device turn green, which is a configuration that results from being coupled to eigenstate with eigenval...
by Tchebu
Sun Mar 17, 2013 6:57 am UTC
Forum: Science
Topic: Quantum Physics Interpretation
Replies: 44
Views: 7248

Re: Quantum Physics Interpretation

Yeah, of course, but those off-diagonal terms simply indicate the imperfection of the measurement and can be made arbitrarily small depending on the specifics of the coupling between the systems. It's essentially the same as perfect voltmeters being impossible because they always have finite resista...
by Tchebu
Sun Mar 17, 2013 6:11 am UTC
Forum: Science
Topic: Quantum Physics Interpretation
Replies: 44
Views: 7248

Re: Quantum Physics Interpretation

By measurement, I mean a process described by the usual unitary time evolution of the measured system coupled to the measurement apparatus which evolves a state (a|a>+b|b>+...)|something> into the entangled state a|a>|A>+b|b>|B>+... the density matrix is then simply the density matrix which describe...
by Tchebu
Sun Mar 17, 2013 12:43 am UTC
Forum: Science
Topic: Quantum Physics Interpretation
Replies: 44
Views: 7248

Re: Quantum Physics Interpretation

After measurement, my measuring device is described by a density matrix, which is diagonal in the basis corresponding to the possible measurement outcomes. So essentially the state is a classical probabilistic ensemble. This is exactly the statement that "I always get an [outcome corresponding ...
by Tchebu
Fri Mar 15, 2013 4:56 pm UTC
Forum: Science
Topic: Quantum Physics Interpretation
Replies: 44
Views: 7248

Re: Quantum Physics Interpretation

I'm surprised by people who find many world's plausible. I think its because they've never tried to do calculations with it. Take the Von Neumann axioms, get rid of the measurement axiom, and actually try to calculate something. You will not get very far. The calculations we do don't depend on the ...
by Tchebu
Thu Mar 14, 2013 6:40 pm UTC
Forum: Science
Topic: Quantum Physics Interpretation
Replies: 44
Views: 7248

Re: Quantum Physics Interpretation

Where's the "shut up and calculate" interpretation?... oh, right, Everett...
by Tchebu
Wed Feb 27, 2013 1:24 am UTC
Forum: Science
Topic: Higgs boson analogy question
Replies: 5
Views: 2446

Re: Higgs boson analogy question

The Higgs being stuck in that valley and only moving along it is what I referred to when I said the Higgs gains a non-zero value at low energies. Moreover, one neat (and somewhat important technical) detail is that massive bosons generally have one extra degree of freedom compared to their massless ...
by Tchebu
Tue Feb 26, 2013 2:44 am UTC
Forum: Science
Topic: Higgs boson analogy question
Replies: 5
Views: 2446

Re: Higgs boson analogy question

I never liked the syrup analogy either... Consider electromagnetism. Charge is basically the ability of particles to interact with the electromagnetic field and a charge placed in some background EM field has some potential energy by virtue of interacting with the field. Now... at low energies the H...

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