Questions tagged [coherent-states]
The specific quantum state of the quantum harmonic oscillator, often described as a state which has dynamics most closely resembling the oscillatory behavior of a classical harmonic oscillator. It obeys the minimal uncertainty relation in Heisenberg's uncertainty relationship.
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What is the best way to describe a classical field in quantum field theory (coherent state)?
In quantum field theory, we have the following expansion on a scalar field (I follow the convention of Schwarz's book)
$$\phi(\vec{x},t)=\int d^3 p \frac{a_p exp(-ip_\mu x^\mu)+a_p^{\dagger}exp(ip_\mu ...
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What is the meaning of the time evolution of a product of coherent states of the QHO?
I am trying to analyze the dynamics of a coupled quantum harmonic oscillator (cQHO) system. The Hamiltonian of the system is given by:
\begin{equation}
\hat{H}_{Coupled}=\frac{1}{2m}\sum_{j}\hat{p}_{j}...
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What does "Coherent" mean in coherent spectroscopy?
I find this on wiki: "Coherent or resonance spectroscopy are techniques where the radiative energy couples two quantum states of the material in a coherent interaction that is sustained by the ...
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Off-diagonal elements of density matrix in three-level system
In a three-level system, let's say an atom with three possible states, $|1\rangle$ being the lowest and $|3\rangle$ the highest ($E_1<E_2<E_3$), where
$$\Psi(t)= C_1(t)|1\rangle+C_2(t)|2\rangle+...
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Difference between Wigner function in coherent space and coordinate space
Such a density operator $\hat{\rho}$ match with a Wigner function in coherent space: $$W(\alpha,\alpha^{*})$$
$\alpha$ and $\alpha^{*}$ are $C-number$ ( $\alpha^{*}$ denotes complex conjugate of $\...
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Does the number of photons in a displaced coherent state is same as the original coherent state? [closed]
Lets say I receive a quantum state $|\alpha\rangle$ with number of photons $N$ and I displace this state by $\alpha$ $\hat D(\alpha)$ so the resultant state is $|2\alpha\rangle$ with same number of ...
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Why can we arbitrarily set the expectation value of a field operator by representing the field state as a product of coherent states?
In the paper "Unusual Transitions Made Possible by Superoscillations", the author begins by solving for a coherent state \begin{equation}|\alpha\rangle\end{equation} such that
\begin{...
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Correspondence between terms in generic path integrals
In field theory, starting with a quantum Hamiltonian with field operator $c$, no matter its nature, one obtains the path integral formulation with partition function $$Z=\int DcDc^* \exp{ -S^1_E[c,c^*...
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Is $SU(2)$ coherent state normalized?
I know Glauber coherent state are normalized such that the inner product of < α|α > =1 where |α > is Glauber coherent state.
My question is (is SU(2) COHERENT STATE NORMALIZED)?
I MEAN IF |Z&...
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How Do I Do This Integral? [closed]
I am trying to derive a boson coherent path integral and one part of the derivation is to evaluate/prove
$$
\int d\Psi(\tau) d\Psi^*(\tau) |\Psi(\tau)|^{2n} \exp(-|\Psi(\tau)|^2) = (n!) \pi.
$$
This ...
user261609
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What does "coherent evolution" of an $N$-body quantum system mean?
In classical physics we know of coherence of waves and in quantum physics we identify coherent states.
While those are clearly defined concepts/terms, in literature we regularly encouter also that a $...
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Angular momentum coherent states
$\renewcommand\bm[1]{\mathbf{#1}}$
$\renewcommand\h{\hbar}$
$\renewcommand\ket[1]{|#1\rangle}$
$\renewcommand\mean[1]{\langle #1 \rangle}$
$\renewcommand\norm[1]{||#1||}$
Let $\bm{J}$ be an angular ...
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Why do coherent states behave semi-classically, but harmonic oscillator states do not?
A coherent state of the quantum harmonic oscillator is defined as an eigenvector $|\alpha\rangle$ of the annihilation operator $\hat a$ with eigenvalue $\alpha$ or as spatial translations of the ...
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Coherent Elastic Neutrino-Nucleus Scattering Energy Transfer
What is the meaning of coherent elastic in "coherent elastic neutrino-nucleus scattering"? What I understand is when a high energy particle such as neutrino interact with the nucleus as a ...
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Physical intuition for coherent states look like classical
In my course on quantum mechanics, we have seen that coherent states look classical. Since the expectation value of the electric field is similar as for the classical expression. Furthermore they look ...
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