Where to start learning cosmology

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Discussion Overview

The discussion revolves around the prerequisites and foundational knowledge necessary for studying cosmology, including the mathematical and theoretical background required. Participants explore various interdisciplinary fields related to cosmology and debate the importance of specific concepts such as quantum field theory (QFT) and thermodynamics in understanding cosmological phenomena.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that a solid understanding of calculus is essential for any calculations in cosmology.
  • To derive basic equations like the Friedmann equations, knowledge of General Relativity is proposed as necessary.
  • Understanding structure formation may require familiarity with differential equations and series expansions.
  • Math is emphasized as a critical skill for comprehending cosmological concepts, with some recommending specific resources for learning.
  • There is a debate on the necessity of quantum field theory (QFT) for understanding inflation, with some arguing that classical field theory suffices while others assert that QFT is crucial for studying fluctuations in inflation models.
  • Thermodynamics is mentioned as beneficial but not strictly necessary for grasping inflationary dynamics, according to some participants.
  • Several textbooks and resources are suggested for those beginning their studies in cosmology, with varying levels of mathematical intensity.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of QFT for understanding inflation, with no consensus reached. While some argue that it is not required for basic comprehension, others contend that it is relevant for advanced topics and model building. The discussion remains unresolved regarding the exact prerequisites for studying cosmology.

Contextual Notes

Participants note that the level of depth in cosmological studies can influence the prerequisites needed, and there are various interpretations of the importance of specific mathematical and theoretical concepts.

Entr0py
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What are the prerequisites you need to have under your belt before you start studying cosmology? And frankly due to my naïveté, I'm not sure of any interdisciplinary fields in cosmology so I know my question is vague
 
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Entr0py said:
What are the prerequisites you need to have under your belt before you start studying cosmology? And frankly due to my naïveté, I'm not sure of any interdisciplinary fields in cosmology so I know my question is vague
It depends a little bit upon what level of depth, but to do any sort of calculations at all you'd need to at least have calculus under your belt.

To learn how to derive the basic equations (such as the Friedmann equations), you'd need some understanding of General Relativity.

In order to get into more complicated things such as structure formation you'd need to have a decent grasp of differential equations and series expansions.
 
Chalnoth said:
It depends a little bit upon what level of depth, but to do any sort of calculations at all you'd need to at least have calculus under your belt.

To learn how to derive the basic equations (such as the Friedmann equations), you'd need some understanding of General Relativity.

In order to get into more complicated things such as structure formation you'd need to have a decent grasp of differential equations and series expansions.
Thanks for the response. By the way do you know any good websites devoted to cosmology?
 
Math is the most vital ancillary skill. It will apply to almost everything cosmological. This article may be a useful primer: http://www.ams.org/samplings/feature-column/fcarc-cosmology. Without strong math skills, most modern cosmology papers are about as easy to understand as hieroglyphics. There is, of course, nothing to stop you from reading popular articles on cosmology, but, you will find yourself compelled to accept many things on faith, which becomes unsatisfying as your curiosity expands. For a nice collection of popular cosmology articles you might try http://www.astro.ucla.edu/~wright/cosmolog.htm. I try to avoid articles written by non-scientists. They tend to confuse as much as enlighten.
 
I thought for understanding early universe and inflation, its vital to know QFT(or QFT on curved ST?).
 
No QFT isn't needed to understand inflation. A good set of math skills and thermodynamics understanding is sufficient. Though GR does help along with QM.

The common formula used in inflation is the equations of state for scalar modelling. This is your thermodynamic portion. One major aspect in both GR and cosmology is both the FLRW metric and Einstein field equations employ the ideal gas laws.

The scalar modelling EOS can be found on this link.

https://en.m.wikipedia.org/wiki/Equation_of_state_(cosmology)

As mentioned before one needs to be able to employ the math, that math relies on differential geometry , strong statistical mechanics is also a good asset.

This site has 3 good preliminary textbooks.

http://www.feynmanlectures.caltech.edu/

Now as far as QFT itself is concerned, it's good to have some particle physics understanding in regards to inflation and Early universe dynamics. However the necessary details can be learned through either Quarks and Leptons

https://www.amazon.com/dp/0471887412/?tag=pfamazon01-20

or Griffiths Introductory to particle physics.

http://www.amazon.com/dp/3527406018/?tag=pfamazon01-20.

Here is two free resources. One being a full length free textbook.

http://arxiv.org/pdf/hep-th/0503203.pdf "Particle Physics and Inflationary Cosmology" by Andrei Linde
http://www.wiese.itp.unibe.ch/lectures/universe.pdf:" Particle Physics of the Early universe" by Uwe-Jens Wiese Thermodynamics, Big bang Nucleosynthesis

For the needed math in particle physics a good free resource is

http://arxiv.org/abs/0810.3328 A Simple Introduction to Particle Physics

http://arxiv.org/abs/0908.1395 part 2

The first book is primarily a coverage of differential geometry. 90+% of it, the second book steps you into GR.

GUT theories, are a bit trickier, in the coupling constants and is largely model dependent, (standard model vs SUSY and SO(10) , both MSM- minimial standard model or Minimal super symmetric ).

It's handy to be familiar with the basis of GUT but not necessarily required. Unless you wish to develop your own models.

Here is a decent coverage, the previous references will greatly help to understand this article.

http://pdg.lbl.gov/2011/reviews/rpp2011-rev-guts.pdf GRAND UNIFIED THEORIES

Two excellent intro level cosmology textbooks is Barbers Rydens Introductory to Cosmology.

http://www.amazon.com/dp/0805389121/?tag=pfamazon01-20

and
Introduction to Cosmology by Matt Roose.
https://www.amazon.com/dp/047084910X/?tag=pfamazon01-20

Both are excellent entry low math intensive textbooks.

Modern Cosmology by Scott Dodelson
Requires greater math skills
https://www.amazon.com/dp/0122191412/?tag=pfamazon01-20
As well as Physical Foundations of Cosmology by Muchanov.
http://www.amazon.com/dp/0521563984/?tag=pfamazon01-20
 
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Mordred said:
No QFT isn't needed to understand inflation. A good set of math skills and thermodynamics understanding is sufficient. Though GR does help along with QM.
I have to disagree with this. Sure, classical field theory is sufficient to understand the dynamics of the inflaton field itself, but we need QFT to study its fluctuations. Much research on inflation deals with these fluctuations and their effect on the CMB, so I'd say it's quite relevant. And I'd say that thermodynamics is not really necessary for understanding inflationary dynamics (though it's of course invaluable for early universe cosmology in general).
 
Agreed but the Op is looking for Where to begin to understand Cosmology. One doesn't need to fully understand QFT to understand the basics of inflation.
 
Entr0py said:
What are the prerequisites you need to have under your belt before you start studying cosmology? And frankly due to my naïveté, I'm not sure of any interdisciplinary fields in cosmology so I know my question is vague
 
  • #10
bapowell said:
I have to disagree with this. Sure, classical field theory is sufficient to understand the dynamics of the inflaton field itself, but we need QFT to study its fluctuations. Much research on inflation deals with these fluctuations and their effect on the CMB, so I'd say it's quite relevant. And I'd say that thermodynamics is not really necessary for understanding inflationary dynamics (though it's of course invaluable for early universe cosmology in general).
Yes, you do need QFT to do sensible inflation model building. But it's possible to grasp the simpler inflation models without that. QFT can also be good for understanding dark matter production and solutions to baryon asymmetry. I'd claim that all of these topics are quite advanced, however, and not necessary for somebody to get started in cosmology.

Not that QFT isn't itself very interesting, but it's also quite difficult.
 
  • #11
Mordred said:
No QFT isn't needed to understand inflation. A good set of math skills and thermodynamics understanding is sufficient. Though GR does help along with QM.

The common formula used in inflation is the equations of state for scalar modelling. This is your thermodynamic portion. One major aspect in both GR and cosmology is both the FLRW metric and Einstein field equations employ the ideal gas laws.

The scalar modelling EOS can be found on this link.

https://en.m.wikipedia.org/wiki/Equation_of_state_(cosmology)

As mentioned before one needs to be able to employ the math, that math relies on differential geometry , strong statistical mechanics is also a good asset.

This site has 3 good preliminary textbooks.

http://www.feynmanlectures.caltech.edu/

Now as far as QFT itself is concerned, it's good to have some particle physics understanding in regards to inflation and Early universe dynamics. However the necessary details can be learned through either Quarks and Leptons

https://www.amazon.com/dp/0471887412/?tag=pfamazon01-20

or Griffiths Introductory to particle physics.

http://www.amazon.com/dp/3527406018/?tag=pfamazon01-20.

Here is two free resources. One being a full length free textbook.

http://arxiv.org/pdf/hep-th/0503203.pdf "Particle Physics and Inflationary Cosmology" by Andrei Linde
http://www.wiese.itp.unibe.ch/lectures/universe.pdf:" Particle Physics of the Early universe" by Uwe-Jens Wiese Thermodynamics, Big bang Nucleosynthesis

For the needed math in particle physics a good free resource is

http://arxiv.org/abs/0810.3328 A Simple Introduction to Particle Physics

http://arxiv.org/abs/0908.1395 part 2

The first book is primarily a coverage of differential geometry. 90+% of it, the second book steps you into GR.

GUT theories, are a bit trickier, in the coupling constants and is largely model dependent, (standard model vs SUSY and SO(10) , both MSM- minimial standard model or Minimal super symmetric ).

It's handy to be familiar with the basis of GUT but not necessarily required. Unless you wish to develop your own models.

Here is a decent coverage, the previous references will greatly help to understand this article.

http://pdg.lbl.gov/2011/reviews/rpp2011-rev-guts.pdf GRAND UNIFIED THEORIES

Two excellent intro level cosmology textbooks is Barbers Rydens Introductory to Cosmology.

http://www.amazon.com/dp/0805389121/?tag=pfamazon01-20

and
Introduction to Cosmology by Matt Roose.
https://www.amazon.com/dp/047084910X/?tag=pfamazon01-20

Both are excellent entry low math intensive textbooks.

Modern Cosmology by Scott Dodelson
Requires greater math skills
https://www.amazon.com/dp/0122191412/?tag=pfamazon01-20
As well as Physical Foundations of Cosmology by Muchanov.
http://www.amazon.com/dp/0521563984/?tag=pfamazon01-20
Awesome reply. Very informational
 
  • #12
Entr0py said:
What are the prerequisites you need to have under your belt before you start studying cosmology? And frankly due to my naïveté, I'm not sure of any interdisciplinary fields in cosmology so I know my question is vague
I don't understand. If you are interested. If you are DRAWN to cosmology, and have some first year college calculus and physics, why wouldn't you start learning cosmology and see how much makes sense to you?

Why WAIT?
 
  • #13
There are plenty of undergraduate astronomy courses at most universities. Many require calc I, but, not all. It is still a nice plus and you won't get very far without a firm math background..
 

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