Fock space versus Heisenberg Algebra

In summary: Your Name]In summary, the conversation focused on the idea of searching for a moduli space to parametrize states in the Fock space. The forum user suggested using a mapping to the Heisenberg Algebra, but there were concerns about the limitations of this approach. There was also discussion about the vacuum state and its role in this approach. Further insights and feedback from experts in the field were suggested.
  • #1
rubbergnome
15
0
Hello everyone. I was kind of "working on a project" when I stumbled onto something, which I can't get if it's wrong or just shallow; it must be wrong, because I haven't seen it anywhere and it seems a quite general statement.

Suppose we are given a bosonic Fock space H generated in the usual manner by acting which any number of creation operators, which can be fields [itex]\psi^\dagger (x)[/itex] which create particles at chosen spacetime positions or their modes [itex]a^\dagger (k)[/itex] which create particles at chosen spacetime momenta. The underlying space of positions is not [itex]\mathbf{R}^3[/itex] in my case, but I don't think it changes things much.

Let [itex]|0\rangle[/itex] be the vacuum. Then, as usual, we act with [itex]N = n + m[/itex] operators

[itex]|x_1,x_2,...,x_n ; k_1,k_2,...,k_m\rangle = \prod_{i,j=1}^{n,m} \psi^\dagger(x_i)a^\dagger(k_j)|0\rangle[/itex].

As in my case, every state in the Fock space represents a geometrical object in a sense, i thought of searching for a moduli space in which coordinates could parametrize these states. I thought that if one sets a maximal number [itex]N[/itex] of particles, one needs for every [itex]n \leq N[/itex] a sequence of [itex]n[/itex] coordinates, let them be positions or momenta. Then, one can rearrange these coordinates in a triangular [itex]N \times N[/itex] matrix. As the underlying vector space of positions/momenta is equipped in my case with an abelian product law, giving it in fact an algebra structure, cannot one consider this a mapping to the Heisenberg Algebra, as it is isomorphic to the algebra of triangular matrices? The commutation relations can be carried along as there is a distinction between position and momentum in coordinates.

The identity element would not be the vacuum, I think, but the zero vector. Maybe one could give the matrix algebra another row/column to get coordinates for [itex]N=0[/itex] which corresponds to the vacuum; and then take the quotient of the algebra with a suitable equivalence relation/group such that the resulting algebra gives only one vacuum. Where am I wrong?

I also didn't know whether to post this in this section or the Mathematics section, as the question is related to both. Move this thread as you please, of course. Thanks in advance.
 
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  • #2

Thank you for sharing your thoughts and ideas on this topic. I would like to offer some insights and feedback on your post.

Firstly, your idea of searching for a moduli space to parametrize states in the Fock space is an interesting one. However, I would caution against assuming that every state in the Fock space represents a geometrical object. While some states may have a geometric interpretation, it is not necessarily true for all states. It would be important to carefully consider the physical meaning and interpretation of the states in the Fock space before attempting to parametrize them.

Regarding your suggestion of mapping the coordinates to the Heisenberg Algebra, this approach may have some limitations. The Heisenberg Algebra is a mathematical structure used to describe the commutation relations between operators in quantum mechanics. While it may be isomorphic to the algebra of triangular matrices, it is not clear how this would help in parametrizing the states in the Fock space.

Furthermore, I am not sure I understand your suggestion of adding an extra row/column to the matrix algebra to account for the vacuum state. The vacuum state is an important concept in quantum mechanics and it is not clear how it would fit into this approach.

In conclusion, while your idea of searching for a moduli space to parametrize states in the Fock space is intriguing, I would suggest carefully considering the physical implications and limitations of this approach. It may also be helpful to consult with experts in the field for further insights and feedback.
 

Related to Fock space versus Heisenberg Algebra

1. What is Fock space?

Fock space, also known as Fock or boson Fock space, is a mathematical concept used in quantum field theory to describe the states of a quantum system with an infinite number of degrees of freedom. It is a vector space constructed from a single-particle Hilbert space, where each basis vector represents a different number of particles in the system.

2. What is the Heisenberg algebra?

The Heisenberg algebra, also known as the Heisenberg-Weyl algebra, is a set of mathematical relations that describe the uncertainty principle in quantum mechanics. It consists of three operators - position, momentum, and time - that do not commute with each other. This algebra is fundamental to the study of quantum mechanics and plays a crucial role in many applications, including the Fock space.

3. How are Fock space and the Heisenberg algebra related?

Fock space and the Heisenberg algebra are closely related as they both deal with the quantum nature of particles. Fock space is used to describe the states of a quantum system, while the Heisenberg algebra describes the fundamental uncertainties in measuring these states. The operators in the algebra are used to create and annihilate particles in the Fock space, making them intertwined concepts in quantum field theory.

4. What are the differences between Fock space and the Heisenberg algebra?

The main difference between Fock space and the Heisenberg algebra is that Fock space deals with the states of a quantum system, while the Heisenberg algebra deals with the operators that describe the system. Fock space is a vector space, while the Heisenberg algebra is a set of mathematical relations. Additionally, Fock space is used in quantum field theory, while the Heisenberg algebra is a fundamental concept in quantum mechanics.

5. How do Fock space and the Heisenberg algebra impact scientific research?

Fock space and the Heisenberg algebra have a significant impact on scientific research, particularly in the fields of quantum mechanics and quantum field theory. They provide a framework for understanding the quantum nature of particles and have numerous applications in fields such as condensed matter physics, particle physics, and quantum computing. These concepts have also led to the development of new technologies, such as superconductors and quantum sensors, that have revolutionized scientific research and everyday life.

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