@Secret ah, excellent, some fluid dynamics terms. was struggling myself. the fluid has both isotropic and heterogenous properties. space is closer to isotropic. matter is closer to heterogenous/ high density. the key aspect of holographic/ correlation aspects is that fluid waves are like/ essentially correlated space-time density variations. another key is in pondering the phonon vs photon distinction. photons are "sampled" phonons (spacetime waves). sampled by...atoms!
> In summary, Statistical Independence is not something that can be directly tested by observation or by experiment because it implicitly draws on counterfactual situations, mathematical possibilities that we do not observe and that, depending on one’s model or theory, may or may not exist.
Well eh... if the statistical dependence is ontic (i.e. it reflects something about real life) it is technically telling us what governs reality at the largest scale
because they understood relatedness way better than any western physicists Yeah, let's hope the universe is not really a tangled ball of dependence like the new agers like to say...
otherwise it will be the end of analytic science lol
"When white radiation is passed though..." - In this context, does the "white radiation" refer to the visible white light (combination of wavelengths in the visible region) or X-rays?
Ok. It's from the following question: > When white radiation is passed though a sample of hydrogen gas at room temperature, absorption lines are observed in Lyman series only.
It seems to make sense only if "white radiation" is from X-rays else we need to have Balmer instead of Lyman.
Fine. Then, it seems we'd refer to the entire electromagnetic spectrum as "white radiation" and not specifically X-rays. Did I understand that statement properly?
> One may debate whether it makes sense to speak of free will even in the second case since a deterministic theory implies that the outcome of any action or decision was in principle fixed at the beginning of the universe. But even adding a random element (as in quantum mechanics) does not allow human beings to choose one of several future options, because in this case the only ambiguities about the future evolution (in the measurement process) are entirely unaffected by anything to do with human thought. Clearly, the laws of nature are a constraint that can
This reminds me of a past dream where I dreamt of something called "superdeterministic randomness"
Thanks. For the statement from my textbook, I think X-rays is the correct choice. Do you know any golden standard for definitions in physics like "The IUPAC Gold Book" for chemistry?
Things look random,but they are not, but your entire memory states are written in such a way you think it is random
That's pretty much The Matrix ver 2
Obviously trying to glitch such a system is one of my personal research in progress
The hypothesis is that: Because of how unfree fate is, there should be a way to cause them to all ram together and eat itself out somehow
If reality is not only superdeterministic, but superdeterministic random, then the first thing I will do is to get a group of researchers to study antisuperdeterministic theory, in order to tear up fate itself lol
because I don't think fate is smart enough to avoid self contradictions
given how any computing systems always have glitches or potential to glitch
> Let us look at a simple example to illustrate why one should not fret about the inability of the experimenter to prepare a state independently of the detector. Suppose you have two fermions. The Pauli exclusion principle tells us that it is not possible to put these two particles into identical states. One could now complain that this violates the experimenter’s free will, but that would be silly. The Pauli exclusion principle is a law of nature; it’s just how the world is. Violations of Statistical Independence, likewise, merely tell us what states can exist according
On another note, I think einselection and decoherance already kinda justify why the state cannot be independent from the detector
> "The ‘big’ measurement problem is the problem of explaining how measurements can have definite outcomes, given the unitary dynamics of the theory: it is the problem of explaining how individual measurement outcomes come about dynamically.
> The ‘small’ measurement problem is the problem of accounting for our familiar experience of a classical or Boolean macroworld, given the non-Boolean character of the underlying quantum event space: it is the problem of explaining the dynamical emergence of an effectively classical probability space of macroscopic measurement outcomes in a quantum measurement process.
@Secret superdeterminism says turn Bell experiments on their head & interpret them as strong evidence for lack of statistical independence in QM measurements, at least in the way that we have "projected" it for over a century. as for reality "conspiring" against us, again, would argue that its a projection, that its actually our own (anthropocentric) biases that "conspire" to confound us. paradigm shifts are neutral but look like a conspiracy against us wrt the "broken/ receding" paradigm...
well technically, Hossefeder have clarified in her arxiv, the statistical dependence only rely on unrealisable counterfactuals, so it actually does not violate compatiblist freewill
in other words, unless reality really do conspire for some reason, we will not end up in my worse case scenario that is the "superdeterministic random" or "Matrix fatalism" reality
unrealisable counterfactuals are already ruled out by the mere existence of the laws of physics, which might explain why reading superdeterminism in details gives me a familiar feeling I have read something like that before in other interpretations
in short, I am open to it
From what I understood so far from the arxiv, superdeterminism basically outsource the factors that generate the randomness into the unrealisable counterfactuals, which science can ignore safely, thus retaining determinism
similar to how bohm oursource randomness to the initial states, and many worlds outsource it to the branches of the global wavefunction
so in a way, all these quantum interpretations are really pieces of a grand puzzle
that is the metametaphysics question: Why do all known quantum interpretations all have a similar theoretical structure
Thus the epeitaphysical question I should be asking is: Why do most of the popular quantum interpretations all have a similar theoretical structure of outsourcing the contradiction to an inaccessible entity?
i mean, the simplest answer is: they're all responses to the same cause, namely the way the QM formalism works. as such, it's not bizarre that their responses are going to have to share features: they're engaging the same underlying issue
particularly since such interpretations are, by their nature, interpretation: they don't predict different phenomena
still there are many ways to deal with a contradiction, outsourcing it is just one of the many possibilities
One thing that makes me favour bohm and objective collapse is that they both try to propose something that can be experimentally tested
(although bohm kinda felt a little bit cop out by saying that the initial conditions are inaccessible)
still, those are way better than other interpretations because they can be experimentally tested
I think collapse theories (and something else I forgot) are the only quantum interpretations I knew that actually deal with the contradiction head on, without postulating that something is inaccessible
@Secret ehhh, the initial conditions are accessible. it's just that, if you access them, you lose the opportunity to see what would have happened had you -not- accessed them
> The distinction between the predictions of quantum mechanics and the predictions of the underlying, superdeterministic theory is not unlike the distinction between climate predictions and weather forecasts. So far, with quantum mechanics, we have made predictions for longterm averages. But even though we are in both cases dealing with a non-linear and partly chaotic system, we can in addition also make short-term predictions, although with limited accuracy. The experiment proposed here amounts to recording short-term trends and examining
Ok I take back what I said about superdeterminism, but sure, an unusual regularity is to be expected for a deterministic theory
If Hossenfer's article generate a similar wave as the surreal trajectory experiment across theoretical physics, then we might saw a resurgence of superdeterministic theories just like what is observed for Bohm resurgence
If the vector L is constant, then (suppose a planet is rotating about a point due to central force) the planet keeps moving in the same plane which is perpendicular to L
And L is always perpendicular to plane of motion
So because the direction and magnitude of L is not changing
@vzn In conclusion: 1. Compatiblist freewill is not violated, so there is no fate nor unscientific problems. People thus should retire the use of the term "free choice loophole" and use "statistical independence loophole" 2. Most of the consequences of statistical dependence is actually common sense based on understanding of decoherence and entanglement 3. Good luck watching a resurgence of superdeterminism research that locate the extremely regular born rule violating state in the coming 3 years. It will be exciting times for quantum theory
I think 0.1. is more likely: which is "quantum experiments will yield exactly what they've always done: the predictions of quantum mechanics, except the results get even more weird and NewScientist will wrote a whole bunch of articles saying how subjective reality is"
too many cat state types experiments from 2015-2019 give me that impression
> In the end, if an experiment is performed based on standard quantum mechanics, and verifies standard quantum mechanics as expected, then it is irrelevant that this aspect of standard quantum mechanics might be analogous to a vaguely-formulated and incomplete speculative idea about spacetime emergence — nor can it provide any experimental support whatsoever for that idea.
that's pretty much the theory-experiment interdependence covered in this standford plato article https://plato.stanford.edu/entries/physics-experiment/
and you're supposed to change groups after the first quiz, so even if they were alphabetical at first, they certainly shouldn't be so for the second quiz
was reading about photonics, I have one question , light is consisting of several color each has different wavelength, and their combined I interfere produce white light, will I see any change in colour of resultant light If change the frequency of two lights?
Or do we always assume the colour source of lights are coherent?
But if you consider, for example, black body radiation this has a continuous spectrum i.e. it isn't made up from a finite number of separate wavelengths.
@YuvrajSingh... No. You are making this more complicated than it really is. White light is a simple mixture of wavelengths. There is no interference or beating going on. Each cone cell in our retina is sensitive to a range of wavelengths, and those 3 ranges have considerable overlap. If a mixture of light has the right amount of energy in each of those 3 ranges then we perceive it as white light.
I'm fairly sure I am asking something different that then the proposed duplicate. And the question itself demonstrates understanding of the proposed duplicate answer
Is there an alternative number to the 100% miscommunicated and hard-to-comprehend "total number of atoms in the universe" cruft
M...
Hello, I'm asking about what makes anti-symmetric tensors (say, of second rank) irreducible. The author de Shalit in his book "Shell Model" gives an argument which states that for an anti-symmetric tensor we can find three non necessary vanishing components, the latter are defined to be components of a vector from the tensor definition.
He added, there is always a transformation acts on any given vector and therefore, it is not possible to find a linear transformation of the components of a vector which transform among themselves under rotations.
My question is, I confused with there exists a transformation for any given vector, and there isn't a transformation of the components of a vector which transform among themselves.
What gets me weird is when we use this argument for a symmetric tensor.
For a symmetric tensor, we have the invariance of trace with respect to the frame of reference.
Therefore, we can reduce this symmetric tensor.
Why, in the second case we used the property of invariance to reduce a tensor, whereas, in the former, we have this transformation but we didn't accept it as an argument to reduce the anti-symmetric tensor?
We're already on "strongly encouraged to stay home" and will likely move to essential personnel only by the end of the week
But, life of the computationalist... Working from home is no big deal, so shutting down doesn't really impact me. I might actually be more productive at home
They are only encouraging us to keep space between each other right now. But I'm expecting my job site to be one of the first places to shut down around here. I can also do a lot of work from home, so I could probably get a good amount done still.
@PM2Ring They are not the same. Pataphysics is basically an art movement that critique science research being too commercialise so they treat everything as equally special
Whereas metametaphysics is an academic field that asks what questions metaphysics asks, its historical patterns and motivations
just as metaphysics basically asks what do our models and assumptions are based on
@Secret struggle with terminology myself. yes getting language right is crucial. even bohr spent decades struggling over exact terminology like precise meanings of "complementarity" etc and it was unfinished in his time. we throw around words that have associated concepts and then realize their definitions are not as precises or what we think. key word to (re)consider, "nonlocality". as for explanations of QM measurment arising from very small scale measurements, believe theyre already here...
"But, it is now known that mathematics is in fact a narrow sub-domain of ichthyology, because if you take 1 fish and put it next to another fish, you have 2 fish. Add another, that’s 3 fish. The rest can be derived from there, and I leave it as an exercise for the reader."
@Student404Mus under a general 3D rotation, the components all mix, so you can't find a subcollection of the components transforming into each other (an $SO(2)$ subgroup would, say, leave the z component unaffected, but no subspace of $R^3$ is left invariant under all $SO(3)$ transformations), and an anti-symmetric tensor is dual to a vector in 3D, so this is another way to see why they transform into themselves
@tpg2114 Plenty of my older colleagues live a rather "offline" life and are now discovering the wonderful world of things like Slack, MS Teams or other remote collaboration tools. It's entertaining to watch the culture shock :P
Am I the only one who thinks the new shade of green in the edit review looks weird/awkward? It's probably just being used to the old colour... but it just doesn't sit right with me.
i.e. Einstein was on the right track he just used too few fields, too few dimensions, too low dimensions for his p-branes, and classical non-quantum thinking :p
Guys... with multiple universities going to online instructions, even for final exams, we should be extremely vigilant about answering "homework-like" questions.
@ZeroTheHero I would say active users on this site shouldn't have to change anything they usually do, but I just reviewed some homework questions where 20k+ rep users answered the questions. So I guess that isn't the case
@ZeroTheHero Downvote and flag for mod attention, there isn't much more you can do. >20kers can in principle vote to delete themselves but since there aren't that many of them and there's no review queue for such delete votes it's not really useful
@AaronStevens We've actually pulled together a list of projects we wanted for various summer interns, time permitting, that could be done in 8-12 weeks. So if the shutdown happens and it lasts more than a couple of weeks such that the experimental folks run out of work to do, we're going to have them power through our project wish list if they want to keep getting paid
@ACuriousMind and @AaronStevens, do you also delete answers to question which are suspected to be homework-like as opposed to ones that are explicitly labeled as such?
@ACuriousMind All of those things are (mostly) banned for us... We just got MS Teams, but it's only accessible from on-site... which makes it less than ideal for remote work.
@kb314 There isn't really such a thing as "suspected to be homework-like". "homework-like" is a close reason that applies to a question regardless of whether or not it is actual homework. People can disagree over whether a given question is homework-like or not, but it does not depend in any way on the OP labeling it as such.
@AaronStevens, unless I am mistaken I was under the impression that it is kosher to post homework questions if the intention is to clarify a conceptual issue. Of course, after having posted complete answers to a few homework-like questions, I now understand that contributors should not do so. @ACuriousMind, I understand. I thought that the moderators use that tag to closely monitor issues related to students attempting to glean solutions off of contributors on physics.se.
@kb314 Yes, you are right. If a question involves an explicit homework question, the question should just be there to provide context to the actual physical principles being asked about
@ACuriousMind, sorry about some of those answers to homework questions. I didn't pay much attention to the type of question or even the explicit 'homework-and-exercises' tag. I apologize!
I think the main use of the tag is so that people can filter it out in their tag settings. There's also a lot of history involved in the "homework(-like) policy" and it can be a bit confusing to understand what exactly is going on for new users.
@AaronStevens, I understand. This se would like to be a place for people to clarify their concepts rather than receiving explicit training on physics problems via crowd-sourcing solutions.
@kb314 No worries, we usually just delete the answers and move on, I'd honestly not have known that I'd deleted some of your answers if you hadn't said so right now :P
@kb314 Yep, you got it :) PSE isn't a homework help site, so we try to keep explicit homework questions and solutions to those questions off of the site
But that doesn't mean homework questions cannot be referred to in a PSE post
Although in my experience most of the time if a question refers to a homework question, it is off topic
@ACuriousMind, it was a little confusing. I just joined up and learning the ropes. But I really like most of the questions and following discussions. I think they are really helpful even when treating elementary concepts. What I find hard is to garner enough attention on questions that are itching me from people who are related to that area.
@AaronStevens, also some bio-physics problems are purely in the domain of mathematical-physics. As such even the latest-and-greatest papers in that area consist of control theoreticians and probabilists. But I agree that for keeping a focused forum, questions (even bio-physics ones) should be curated to be about the physics of any phenomenon.
Ah, if your field is interdisciplinary you have the additional problem that your topic is probably split across several SE sites in an uneven manner, where each site has different ideas about what is on-topic
@Secret, I agree. But people are mostly excited if you can do experiments. For instance, reinforcement learning or in fact all of machine learning is an application of applied statistics to various problems, including optimal control as in RL. However, those methods are directly applicable to show computers playing video games and such... Even academically more profitable than working on the actual physics
Plus if it's interdisciplinary, there's always the chance that any focused site will still not have enough interest in the topic; because too much of it falls outside the sscope, even if it's on topic.
that is true, interdisiniplinary stuff tends to spread across multiple fields which is why it is better to crowd people from relevant disciplines together to discuss in a (video) conference
they are also a lot more applied hence the money factor
Personally, I handle an interdisciplinary question by making tailored versions to all relevant fields
@YuvrajSingh... Aaron and I were describing how the site currently deals with HW-like questions. Do you mean to say that our description was incorrect or that you don't like the way it works?
molecular motors and quantum entanglement in plants are pretty physics heavy for example, bioinformatics is a bit of a mix depending on the nature of the project
@kb314 I think quite a few active users on PSE are educated as engineers and not physicists. I know I am, and quite a few other users around the ~10k range are.
@ACuriousMind I don't dislike how it works, especially on the issue of homework-like questions. But the policy is not communicated in a clear and concise manner, especially to new users. For instance, such a communication must necessarily provide an example of a homework question which can be re-worded to be acceptable and useful to this community.
@JMac and @ACuriousMind, thanks! Makes feel a little less out of place.
@kb314 The homework close banner points users to good examples. Unfortunately without enough reputation you cannot see the close banner unless it is your question
Which I still don't agree with them changing it to work that way
@kb314 I agree. Also for historical reasons, most long-time users are unfortunately pretty burnt-out on discussing the HW-policy and any effort to create new documentation would inevitably rekindle old arguments. So motivation is...rather low.
And additionally, such examples would be useless for most users whose questions are closed as HW because the majority really is just students copy-pasting their exercise into the question box. Such questions usually simply cannot be "reworded" to be on topic because the asker never reaööy had a question about physics to begin with - they just wanted to get points on their homework.
I'm fairly sure I am asking something different that then the proposed duplicate. And the question itself demonstrates understanding of the proposed duplicate answer
Is there an alternative number to the 100% miscommunicated and hard-to-comprehend "total number of atoms in the universe" cruft
M...
