# Questions tagged [second-quantization]

Second quantization or canonical quantization in quantum field theory and many-body systems is the collective organizing and accounting of an infinity of quantum excitations and their interactions through quantum field operators.

594 questions
Filter by
Sorted by
Tagged with
42 views

### Hubbard Model Hamiltonian in matrix form using basis

I am reading material on Hubbard Model (please see this link) "The limits of Hubbard model" by Grabovski, and I have difficulty deriving/calculating hamiltonian in chapter 8. eq.8.2. How ...
59 views

34 views

### Nonzero expectation value of boson creation operator in ground state of a Bose-Einstein condensate

I was following along with these notes, and just above equation (32) on page 3, the author makes the claim that, "for a Bose condensate, the ground state boson creation operator acquires a finite ...
23 views

### Help with path integral formalism for quantum field theory [duplicate]

Recently i was doing some work with quantization of fields. I learned to quantize using the canonical method, writing in terms of the ladder operators. Then I saw that there was a more powerful method,...
61 views

### Confusion with the definition of propagator in canonical quantization and path integral formalism

Imagine the following $1$-loop diagram with two vertices in interacting $\lambda \phi^4$ theory: In momentum space the way to write down the correlator is: Drawing incoming and outgoing legs, ...
1 vote
20 views

### Explaining the DHR superselection theory through specific examples

The DHR superselection theory is an important result in the framework of algebraic quantum field theory that categorizes the set of all physically admissable superselection sectors of an observable ...
43 views

49 views

102 views

### Specific commutator calculation using the path integral

Consider the path integral quantisation of a scalar field $\phi$ on flat spacetime. Let the Lagrangian be $\mathcal{L}$. I would like to prove the following equal time commutation relation: \begin{...
1 vote
53 views

### D-branes mechanics and D-branes field theory

Following those two questions: The different frameworks around the point particle (for $p=0$), The different frameworks around the string (for $p=1$), I was wondering if the discussion could ...
49 views

### The different frameworks around the string

I am studying string theory and I realize that the relations between the different frameworks are not clear to me. Following this question, one could repeat the discussion but now taking $p=1$. We get ...
48 views

### The different frameworks around the point particle

I am studying string theory and I realize that the relations between the different frameworks are not clear to me. Starting from (reativistic) classical mechanics, the "state" of a point ...
32 views

### Intuition & physical interpretation behind asymmetry in applying field operators in second quantization

Equivalently to the simple quantum harmonic oscillator, we define the creation and annihilation operators in second quantization for identical particles with the commutator \$[a_i, a_j^\dagger] = \...
1 vote
129 views

### Why we use fields instead of wave functions?

I'm starting studying QFT and I have a problem about a concept that maybe it's stupid but I don't understand exactly. Why we use fields instead of wave functions? I tried to answer myself, and I found ...