All Questions
Tagged with coherent-states condensed-matter
13
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Majorana Boson Coherent States
Consider $a$ be a bosonic operator, and we define $\Phi = a+a^{\dagger}$ and it is clear that $\Phi^{\dagger}=\Phi$ that implies "Majorana Boson". Now, i want to find the coherent states for ...
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Coherent spin state (CSS) for an electron with spin
Standard definition for the spin coherent state (CSS) for the system of $N$ identical particles reads
$$
|\theta, \phi\rangle = \bigotimes\limits_{k=1}^{N} \left[ \cos\frac{\theta}{2} |0\rangle_k + e^{...
- 227
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Identity of bosonic coherent states
I have a short question about the meaning of the identity of the bosonic coherent states.
Before I ask the question I will explain some background.
The eigenstate of the bosonic annihilation operator $...
- 237
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$U(1)$ symmetry transformations in second quantization confusion
I'm reading Chapter 18 (BEC and Superfluidity) of Girvin and Yang and ran into some confusion.
Let $|\alpha\rangle = e^{-|\alpha|^2}e^{\alpha b^†_0}|0\rangle $, where $\alpha$ is just a complex ...
9
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Calculating free energy from coherent state path integral
Edit: It turns out that problem encountered in this question is not limited to BdG Hamiltonians.
I am having trouble in using the coherent state path integral approach to calculate the free energy. ...
- 660
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Questions of fermionic coherent states (page 166 of Atland and Simons)
This is quite a basic question but I just can not find the solution.
The question is how do you show equation (2) below. Let me explain the details.
From page 166 of condensed matter book by Atland ...
- 311
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Representing Green function as a coherent state path integral
I am working through the problem "self-consistent T-matrix approximation" in Altland and Simons (second edition) pg 234. One of the steps involves representing the Green function as a ...
-2
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1
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Inner product of bosonic coherent states [closed]
In the notation of Altland and Simons, we have bosonic coherent state:
$$
|\phi\rangle = \exp \left(\sum_i \phi_i a_i^\dagger\right) |0\rangle.
$$
On page 159, they use $\langle0|\phi\rangle = 1$ ...
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Is there symmetric form for statistical action?
In quantum statistical theory, for a given Hamiltonian $H$, one can express the partition function as
\begin{equation}
Z = \text{tr}\, e^{-\beta H}
\end{equation}
into the coherent path integral ...
- 11
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How to calculate spin correlation function via spin coherent state?
I am following the Section 8.3.1 of Auerbach. I want to calculate spin correlation function via spin coherent state, i.e. the equation (8.28):
$$\begin{aligned}\left\langle\mathbf{S}_{m} \cdot \mathbf{...
- 1,602
2
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Is the superfluid state a coherent state?
In the normal to a superfluid phase transition, U(1) symmetry related to particle number conservation is spontaneously broken which seems to imply that the superfluid state is a state in which there ...
- 26.8k
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Connection between Hubbard-Stratonovich and (generalized) coherent states
A simple-minded mean-field approximation for the Bose-Hubbard model consists in writing operators as $\hat{a}_i = \alpha_i + \hat{\delta \alpha}_i, \alpha_i \in \mathbb{C}$ and only include terms up ...
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11
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2
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Why use coherent state path integral? What is its motivation or goal?
In almost all textbooks of quantum field theory for high energy, they insert the position and momentum eigenstate to formulate the path integral. While in condensed matter field theory, they insert ...
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