/sci/ - Science & Math

>tfw no physicalism (because of qualia)

>>9112343
What do you think it is?

>>5914557
>>5914561
Theoretical physics has disproven objectivism.

>>5567852
Are you implying physicists do not care about generality? ;-) I know many people (myself included) who do string topology, if you could consider that a "mathematician" - they love A and B models. Some algebraic geometers are, in a sense, working with actional functionals

>>5567841
How do you know this? If >>5566596 is the OP, which I assume He is, "generalized case" could mean anything.

>>5567817
http://ncatlab.org/nlab/show/generalized+smooth+space

>>5567835
Okay, I give up.

>>5567832
That should be
<span class="math">\displaystyle\Omega_{\mathrm{loc}(\mathcal{F}\times M)[/spoiler]

>>5567832
That should be <span class="math">\Omega_{\mathrm{loc}(\mathcal{F}\times M)[/spoiler].

>>5567814
Until he specifies what exactly <span class="math">X[/spoiler] is allowed to be, you are unable to do any true computations in superspace. Although his second equation appears to only have dependence on the 1-jet, <span class="math">\Omega_{\mathrm{loc}(\mathcal{F}\times M)[/spoiler] may be nontrivial or nonexistent based on whatever the superfield maps into.

None of it. We do not experience "perception", we experience qualia. Qualia are induced by perception. The perception alone is without qualia.

>>5567714
Forgetting that zeta function regularization implies the stability of our vacuum. ;-)

What is <span class="math">X[/spoiler] allowed to map into? Your answers will obviously be dependent on this.

>>5566449
To add to >>5567692, an orbifold really does not really require the notion of a manifold, just a "generalized smooth space"- at least this is how it is defined in the context of string theory, in Joe's textbook for example. Generally the group will act with finite stabilizers also.

>>5566305
Good answer, although it should also be mentioned that these "kinks" are not to be taken as singularities, divergences, or any other kinds of physical inconsistencies. They may be treated smoothly using dual descriptions.

>>5565468
This is just breathtakingly incorrect. I see that you must believe this comment is intelligent but it is not necessarily so. You are creating a false analogy - you cannot compare cutting-edge physics with vague pseudo-science that boasts order-of-magnitude errors and pseudo-philosophical babbling.

Are there any other serious laymen misconceptions ITT or is it simply a gang of quasi-religious, psychiatrically ill bigots spewing incoherent and illogical crackpot proclamations about string theory?

>>5565251
Assuming you are lacking an acquaintance with Physics, there is an entire website dedicated to this question: http://whystringtheory.com/

But I think the fact that string theory is able to qualitatively describe and predict every observation we have done - and there are literally trillions of these - with just a single input parameter, the fact that it is directly implied by the mathematical structure of the standard model, the fact that there are no alternatives, the fact that there is inevitably quantization of gravity + unification of all matter/force fields, and the fact that the theory cannot be deformed/modified without spoiling its consistency are some of the "leading" reasons to be convinced that it is "probably true".

>>5434943
That is quite hard to beat ;-), I would have to opt for the non-commutative analogue or

<div class="math">\mathcal H^r(\mathcal M)=\bigoplus_{p+q=r}\mathcal H^{p,q}(\mathcal M),\;\mathcal H^{p,q}(\mathcal M)=\overline{\mathcal H^{q,p}(\mathcal M)}</div>
For complex M, pic very related.
>>5435037
Not him, but I found Higson and Roe's "Analytic K-Homology" to have a decent and modern review in terms of the algebraic K-theory. Nothing is better than the original papers, however.
>>5435058
It is the Atiyah-Singer index theorem, a beautiful result in the study of manifolds with endless applications. In general, the theorem allows us to calculate certain analytic data - the indices i.e. sums and differences of the numbers of independent solutions to differential equations of various kinds - in terms of topological data about the base manifold, e.g. the Betti numbers or the number of holes in the manifolds. The index of the Dirac operator for example is important to physicists as it determines the number of generations of leptons and quarks in the conventional compactifications of string theory with 6 internal dimensions, among numerous other things.

>>5434943
That is quite hard to beat ;-), I would have to opt for the non-commutative analogue or

<div class="math">\Omega^k(M)=\rm{im}\Delta_k\oplus\ker\Delta_k=\Delta(\Omega^k(M))\oplus\mathcal H^k;~~\forall\alpha\in\Omega^k(M),\;\exists\omega\in\Omega^k(M):\Delta\omega=\alpha\Longleftrightarrow \alpha\perp\mathcal H^k</div>
For complex M, pic very related.
>>5435037
Not him, but I found Higson and Roe's "Analytic K-Homology" to have a decent and modern review in terms the aspects of algebraic K-theory. Nothing is better than the original papers, however.
>>5435058
It is the Atiyah-Singer index theorem, a beautiful result in the study of manifolds with endless applications. In general, the theorem allows us to calculate certain analytic data - the indices i.e. sums and differences of the numbers of independent solutions to differential equations of various kinds - in terms of topological data about the base manifold, e.g. the Betti numbers or the number of holes in the manifolds. The index of the Dirac operator for example is important to physicists as it determines the number of generations of leptons and quarks in the conventional compactifications of string theory with 6 internal dimensions, among numerous other things.

The number of breathtakingly stupid mental defects squeezed into this post is just astronomical. What kind of neurological pygmy simultaneously allows for this incompetent drivel and the technical abilities necessary for computer use?

>>5282928
>if some evidence contrary to M-theory comes up, they'll change it to make it work out and say it's still valid. There's a difference.
Why do you recite this parasitic, kibitz, pseudointellectual ideology? It is just unbelievably dishonest. Where have you acquired this information from? Do you have a source for this crackpottery, or are you just babbling philosophical nonsense that you irrationally convince yourself to be true on an emotional basis?

Unlike the standard model or quantum field theory, it is impossible "deform" or "change" string theory "to make it work". All of the solutions are exact. Any deformation will render the theory non-unitary, leading to the violation of basic postulates of quantum mechanics. This means a very specific thing; it may be demonstrated by very specific techniques, and understanding why it is true is completely essential to understanding why the term "string theory" exists and why we study it at all. If something prevents you from learning the technical insights linked to this point, you can't really start to understand what string theory is.

>>5283500 cont
To make the predictions specific, one needs to deal with a particular quantum field theory (the standard model) which means one must determine the field content and the parameters; there is an analogous extra choice - the choice of the right discrete compactification - in string theory that is needed to produce the equivalent predictions of string theory. There are compactifications of string theory that have the standard model field content at low energies, after SUSY breaking (below all these other scales of new physics).

Your suggestion that the string theory “is the start of a religion” is just a proof that you don't have the slightest clue what you're talking about. If you agree on the validity of the way standard model particle physics is done, your "argument" is equivalent to an argument against quantum mechanics in the 1920s saying that a potato looks classical, so it's a problem for quantum mechanics. Just to be sure, this "argument" is invalid because according to quantum mechanics, a potato also behaves in a similar way as classical physics used to predict. Still, the right theory - for atoms as well as potatoes - is quantum mechanics.

>>5282916
>M-theory is untestable
String theory is the only theory in the quantum gravity regime to provide testable predictions. It is the only theory containing a finite landscape of vacuum solutions, each located on a point of configuration space. These are “self-contained theories of everything”, meaning each vacuum will predict all the observable phenomena that can ever occur. We eliminate vacua that are not our own by analyzing collider data. Eventually, and without any need for Planck-scale experiments, we will find our own vacuum. It may even happen within our lifetimes.

>pretty damn close to unfalsifiable, sounds like the start of a religon to me.
Do you consider quantum electrodynamics a religion as well? Or evolution? I mean, both of these are also "pretty damn close to unfalsifiable". It is very hard to falsify a very promising theory - almost by definition. A promising theory is a theory that seems consistent with all/most things we can see right now. That fact that these things are harder to falsify but at the same time qualitative just means that they are more likely to be correct. "Religion" does not contain any sort of qualitative framework, it does not make predictions, and it is very much so falsified by observation (evolution, unmalleable physical laws, etc).

To clarify your misconception, though, in the standard model we deal with a particular field content that has to be extracted from the experiments, much like the coupling constants and masses; in the same way, there are compactifications of string theory and the data equivalent to the particle content and parameters - which compactification - has to be extracted from the experiment.

>>5282909
>It's M-theory now.
This is breathtakingly incorrect. M-theory is the maximally decompactified aspect of string theory, but this does not imply it is more "fundamental" or can replace "string theory". All of the string theories, including M-theory, are equivalent to one another via dualities.