An Introduction to Quantum Field Theory
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An Introduction to Quantum Field Theory
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Re: An Introduction to Quantum Field Theory
#2This is a great article. One thing I don't understand: the author says:
> If you want to create something heavy like the Higgs boson, you have to hit the > Higgs field with a sufficiently large (and sufficiently concentrated) burst of > energy to give the field the necessary one quantum of energy.)
So when the LHC creates a spike of energy at a point large enough to create a Higgs boson, why does that energy interact with the Higgs field and get "used up" by other fields? In other words, if Higgs requires 100 units of energy and electrons require 1, why do we get 1 Higgs boson and not 100 electrons?
Re: An Introduction to Quantum Field Theory
#3Are quantum fields actual elements of reality or just a convenient mathematical tool to deal with many particle systems?
One of the questions I am struggling to find a satisfying answer for for quite some time. Depends on whom you ask? We can't tell because both ways of thinking are completely equivalent? Fields are real! No, they are just a tool! Are there issues with real fields forming a preferred reference frame? Does somebody know? (My current understanding seems to suggest that fields are just a tool.)
Re: An Introduction to Quantum Field Theory
#4This is a pretty good introduction. I highly recommend Feynman's book "QED: The Strange Theory of Light and Matter" as an excellent in-depth work that does not sacrifice accuracy for the sake of making difficult ideas understandable. It is both very clear to the layperson and accurate to the physics.
Re: An Introduction to Quantum Field Theory
#5Are quantum fields actual elements of reality or just a convenient mathematical tool to deal with many particle systems? One of the questions I am struggling to find a satisfying answer for for quite some time. Depends on whom you ask? We can't tell because both ways of thinking are completely equivalent? Fields are real! No, they are just a tool! Are there issues with real fields forming a preferred reference frame?…
It depends on what constitutes 'an element of reality'. Are photons an element of reality?
Depending on the field of science/engineering and the specific application, one might choose to work with electromagnetic fields, photons or a combination of both.
In the QFT framework, a photon is merely a quanta of the electromagnetic field. So photon based or EM field based approaches are just two ways of dealing with problems. Neither is more or less 'real' than the other.
Re: An Introduction to Quantum Field Theory
#6This is a great article. One thing I don't understand: the author says: > If you want to create something heavy like the Higgs boson, you have to hit the > Higgs field with a sufficiently large (and sufficiently concentrated) burst of > energy to give the field the necessary one quantum of energy.) So when the LHC creates a spike of energy at a point large enough to create a Higgs boson, why does that energy interact…
Not a physicist, but that actually happens. Depending on the coupling strengths between the various kinds of particles respectively fields and the amount of energy they have, different particles get created with different probabilities. That is why the Higgs is so hard to detect - for every Higgs you produce billions and billions of other particles that are easy to create and you have to look for the one Higgs in all this mess. Physicists calculate the expected amounts of other particles with incredible precision, subtract that from the experimental results and if they are successful they end up with a tiny amount of unexplained stuff.
Re: An Introduction to Quantum Field Theory
#7Ether is back!
Well, somewhat. Now it's in the form of Higgs field. Unlike ether, Higgs field does not interact with uniformly moving particles, only those that are accelerating.
Here's a great book I just recently listened: http://www.amazon.com/The-Black-Hole-War-Mechanics/dp/031601...
It's by Leonard Susskind from Stanford. The thoughts experiments in the book are just terrific. Loved it.
Re: An Introduction to Quantum Field Theory
#8This is a pretty good introduction. I highly recommend Feynman's book "QED: The Strange Theory of Light and Matter" as an excellent in-depth work that does not sacrifice accuracy for the sake of making difficult ideas understandable. It is both very clear to the layperson and accurate to the physics.
It would be nice to have a version that uses complex numbers and linear algebra instead of spinning arrows. A little bit more math would make it easier to connect with the "grown up" version of the theory.
Re: An Introduction to Quantum Field Theory
#9Are quantum fields actual elements of reality or just a convenient mathematical tool to deal with many particle systems? One of the questions I am struggling to find a satisfying answer for for quite some time. Depends on whom you ask? We can't tell because both ways of thinking are completely equivalent? Fields are real! No, they are just a tool! Are there issues with real fields forming a preferred reference frame?…
The way I've understood it is, particles are localized excitations of fields. You know of the Higgs boson. It is the excitation of the Higgs field, which exists through all space. Similarly, an electron is an excitation of the electron field (not electromagnetic field), which exists through all space. Every single electron is a localized excitation of the same, single field.
I don't know how to answer the relativistic questions of fields yet. For that one would need to learn a lot of Quantum Field Theory.
For the layman, however, these two links are very informative:
http://www.symmetrymagazine.org/article/july-2013/real-talk-... http://www.pbs.org/wgbh/nova/blogs/physics/2013/08/the-good-...
Re: An Introduction to Quantum Field Theory
#10This is a great article. One thing I don't understand: the author says: > If you want to create something heavy like the Higgs boson, you have to hit the > Higgs field with a sufficiently large (and sufficiently concentrated) burst of > energy to give the field the necessary one quantum of energy.) So when the LHC creates a spike of energy at a point large enough to create a Higgs boson, why does that energy interact…
When particles are created in the LHC, a huge number of particles are created when particles are collided. This is why physicists have to sift through mountains of data to find the one higgs boson in the flood of every other particle.