# quantum field theory

### A Evolution operator in QFT - why Schrodinger?

I'm reading through a couple of books (Lahiri & Pal's "A First Book of Quantum Field Theory" and Greiner & Reinhardt's "Field Quantization" and...
Thread by: Glenn Rowe, Jul 7, 2018, 16 replies, in forum: Quantum Physics

### I Interactions in QFT and consistent field energy...

I have a not-very-well formulated question about the interaction picture of QFT. I understand that, in an interaction picture, particle numbers...
Thread by: asimov42, Jul 4, 2018, 14 replies, in forum: Quantum Physics

### B What is the difference between a wave and a field?

I've been reading about Quantum Field Theory. It strikes me that since the 1920's, physicists have changed the name "wave" to "field". I can't...
Thread by: Kenneth Boon Faker, Jul 2, 2018, 7 replies, in forum: General Physics

### Quantum Field Theory. Electric discharge

How work triboelectricity in QFT? Materialists exchange electrons as well as in classical theory?
Thread by: arnoldcena3000, Jun 23, 2018, 9 replies, in forum: Quantum Physics

### I Does the Uncertainty Principle imply a linear cosmology?

If the uncertainty in the age of the Universe is $\Delta t$ then the Uncertainty Principle implies that it has an uncertainty in its energy...
Thread by: jcap, Jun 14, 2018, 3 replies, in forum: Cosmology

### I Nonrelativistic limit of scalar field theory

The Klein-Gordon equation has the Schrodinger equation as a nonrelativistic limit, in the following sense: Start with the Klein-Gordon equation...
Thread by: stevendaryl, Jun 12, 2018, 2 replies, in forum: Quantum Physics

### Studying How to self-study advanced books like Weinberg's QFT?

Although the question came to my mind while studying Weinberg's QFT books, the doubt is much more general than that, and is not a doubt about...
Thread by: leo., May 26, 2018, 1 replies, in forum: Academic Guidance

### A Vacuum in QFT: Fock space or effective potential?

There seem to be two ways of defning what a vacuum is in QFT: 1. It is state $|0\rangle$ such that $$a_k|0\rangle = 0$$ for all anihilation...
Thread by: Krudak Krudak, May 14, 2018, 1 replies, in forum: Quantum Physics

### Casimir effect in 1+1 Minkowski spacetime

1. The problem statement, all variables and given/known data https://i.imgur.com/sI3JiB4.jpg https://i.imgur.com/PLpnPZw.jpg I have no idea how...
Thread by: Emil_M, May 11, 2018, 7 replies, in forum: Advanced Physics Homework

### A Is irreducibility justified as a Wightman axiom?

My discussion (copying this from a Facebook post dated April 29th, 2018): A realization that has been steadily growing crystallized for me this...
Thread by: Peter Morgan, Apr 30, 2018, 4 replies, in forum: Quantum Physics

### Mde decomposition of quantum field in a box

1. The problem statement, all variables and given/known data I am considering the Klein Gordon Equation in a box with Dirichlet conditions (i.e.,...
Thread by: DavidDC, Apr 23, 2018, 2 replies, in forum: Advanced Physics Homework

### I A Proof of Kaku (8.18).

In the following there is a proof, for positive values of $a$ only, of (8.18) of Kaku, reference 1, I quote'...
Thread by: rocdoc, Apr 18, 2018, 12 replies, in forum: Quantum Physics

### I Decomposing a Certain Exponential Integral

There is nothing wrong with the well known $$e^{i\theta}=\cos\theta+i\sin\theta$$ for real $\theta$ but what about...
Thread by: rocdoc, Apr 12, 2018, 13 replies, in forum: Calculus

### Feynman Diagrams for Interacting Scalar Fields

1. The problem statement, all variables and given/known data Consider four real massive scalar fields, \phi_1,\phi_2,\phi_3, and \phi_4, with...
Thread by: MyName, Apr 10, 2018, 2 replies, in forum: Advanced Physics Homework

### I Path Integrals in Quantum Theory

I have found a general result for certain exponential integrals that may be of interest to those involved with using path integrals. I am not...
Thread by: rocdoc, Apr 9, 2018, 3 replies, in forum: Quantum Physics

### I Quantum Field Configurations and Wavefunctions

Could anyone explain what a quantum field configuration is, and any relation this concept may have to the idea of a wavefunction? Perhaps for a...
Thread by: rocdoc, Apr 2, 2018, 4 replies, in forum: Quantum Physics

### A Information encoding in the Holographic principle

Can whatever type of information be encoded in a boundary in holographic principle? in a question some years ago regarding holography...
Thread by: Suekdccia, Apr 1, 2018, 14 replies, in forum: Beyond the Standard Model

### Field transformation under Conformal transformation

I am confused about the field transformation under conformal transformation. Consider the scale transformation of field $\phi$ (not necessarily...
Thread by: craigthone, Mar 17, 2018, 5 replies, in forum: Advanced Physics Homework

### A Can disjoint states be relevant for the same quantum system?

In the algebraic approach, a quantum system has associated to it one $\ast$-algebra $\mathscr{A}$ generated by its observables and a state is...
Thread by: leo., Mar 13, 2018, 4 replies, in forum: Quantum Physics

### I Two questions about "The Physics of Virtual Particles"

Arnold Neumaier, I have 2 elementary questions about your article “The Physics of Virtual Particles”. 1. In the paragraph headed “States.” on...
Thread by: fox26, Feb 20, 2018, 9 replies, in forum: Quantum Physics

### A States in usual QM/QFT and in the algebraic approach

Studying QFT on curved spacetimes I've found the algebraic approach, based on $\ast$-algebras. In that setting, a quantum system has one...
Thread by: leo., Feb 14, 2018, 5 replies, in forum: Quantum Physics

### A I want to know the exact problems of Merging GR and QM

This thread is I want a set of experts in the subject to show me the exact math of why Einstein's field Equations along with Special Relativity...
Thread by: VIctor Medvil, Feb 11, 2018, 6 replies, in forum: Beyond the Standard Model
23. Physics and Math Videos

### Quantum Fields: The Real Building Blocks of the Universe - with David Tong

According to our best theories of physics, the fundamental building blocks of matter are not particles, but continuous fluid-like substances known...
Uploaded by: Wrichik Basu, Feb 11, 2018, 0 comments, in category: Quantum
24. Physics and Math Videos

### Quantum Fields with David Tong - Questions and Answers

According to our best theories of physics, the fundamental building blocks of matter are not particles, but continuous fluid-like substances known...
Uploaded by: Wrichik Basu, Feb 11, 2018, 0 comments, in category: Quantum