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What's your background to make such a claim? Are you aware that String theory has made contributions to condensed matter physics and mathematics? Not to speak o

by pa7x1 5y ago

What's your background to make such a claim? Are you aware that String theory has made contributions to condensed matter physics and mathematics? Not to speak of its applications to quantum gravity, for example, being able to calculate the entropy of a black hole from counting microstates.

adrian_b 5y ago
You are too optimistic about the contributions of the string theory. A lot of papers and books have been published about the string theory and all claim to calculate something. As an interesting mathematical model, string theory certainly qualifies. On the other hand, as a mathematical model usable in physics, a theory like string theory must pass 3 criteria: 1. It should be able to calculate some numerical values of physical quantities that can be measured. 2. Those measurements must be made and the results must be as predicted, with a reasonable accuracy. 3. It should not be possible to compute the same numerical values that have been validated by measurements using other simpler mathematical models. I have browsed through many research papers and a few books about string theory and I have never seen any results even remotely approaching the fulfillment of these 3 criteria.
- pa7x1 5y ago
  I think you misunderstand how physical theories work. All physical theories we know have free variables that need to be fixed before being able to make any numerical predictions. In classical electrodynamics it's the permittivity and permeability of the vacuum. In Newton's theory is G. In General Relativity is G and \lambda. In QED is the fine-structure constant, \alpha. And the Standard Model of particle physics has 20 free parameters that have to be set by hand using input from the experiment before being able to use it to make precise numerical computations and having any predictive power. If you don't fix these inputs you don't have a theory, you have a family of theories and you cannot discern which one is the correct one. On top of that, Quantum Field Theory (QFT) the "theory" (continue reading to see why the word theory is a misnomer) that underlies the Standard Model is not constraining enough and you still need to pick the right gauge theories that model our universe. So QFT is better understood as a framework, from which we build a model of reality by hand-picking some theories that seem to suit our universe, then we fix their free parameters using experiments and only then we can predict everything else. String Theory is much the same as QFT in this regard. It's a framework for building physical theories. It arguably has less free-parameters (it has only 1), the string tension. Buy you still need to pick the right models within the framework, here again String Theory is arguably more constraining but you still have an immense amount of options, commonly referred as the String Theory landscape (or vacua) and relate to how you compactify the extra dimensions. So if you applied the same criteria to Quantum Field Theory you would come to the conclusion that is "an interesting mathematical model" but a "useless physical theory". Disclaimer: I studied Theoretical Physics. I do not work in academia or in physics, for that matter. My sustenance does not depend on money flowing into High Energy physics.

by pa7x1 5y ago

adrian_b 5y ago

You are too optimistic about the contributions of the string theory. A lot of papers and books have been published about the string theory and all claim to calculate something. As an interesting mathematical model, string theory certainly qualifies. On the other hand, as a mathematical model usable in physics, a theory like string theory must pass 3 criteria: 1. It should be able to calculate some numerical values of physical quantities that can be measured. 2. Those measurements must be made and the results must be as predicted, with a reasonable accuracy. 3. It should not be possible to compute the same numerical values that have been validated by measurements using other simpler mathematical models. I have browsed through many research papers and a few books about string theory and I have never seen any results even remotely approaching the fulfillment of these 3 criteria.

pa7x1 5y ago
I think you misunderstand how physical theories work. All physical theories we know have free variables that need to be fixed before being able to make any numerical predictions. In classical electrodynamics it's the permittivity and permeability of the vacuum. In Newton's theory is G. In General Relativity is G and \lambda. In QED is the fine-structure constant, \alpha. And the Standard Model of particle physics has 20 free parameters that have to be set by hand using input from the experiment before being able to use it to make precise numerical computations and having any predictive power. If you don't fix these inputs you don't have a theory, you have a family of theories and you cannot discern which one is the correct one. On top of that, Quantum Field Theory (QFT) the "theory" (continue reading to see why the word theory is a misnomer) that underlies the Standard Model is not constraining enough and you still need to pick the right gauge theories that model our universe. So QFT is better understood as a framework, from which we build a model of reality by hand-picking some theories that seem to suit our universe, then we fix their free parameters using experiments and only then we can predict everything else. String Theory is much the same as QFT in this regard. It's a framework for building physical theories. It arguably has less free-parameters (it has only 1), the string tension. Buy you still need to pick the right models within the framework, here again String Theory is arguably more constraining but you still have an immense amount of options, commonly referred as the String Theory landscape (or vacua) and relate to how you compactify the extra dimensions. So if you applied the same criteria to Quantum Field Theory you would come to the conclusion that is "an interesting mathematical model" but a "useless physical theory". Disclaimer: I studied Theoretical Physics. I do not work in academia or in physics, for that matter. My sustenance does not depend on money flowing into High Energy physics.