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Questions tagged [cavity-qed]

Cavity QED is the study of quantum effects in cavities, waveguides or resonators, which enhance the interaction between light and matter.

Cavity quantum electrodynamics (cavity QED or CQED) is the study of the quantum nature of light-matter interaction in resonant cavities and waveguides. The cavity enhances said interaction by modifying the mode environment inside the cavity.

Effects

Quantum effects in CQED include (but are not limited to)

  • Purcell effect: Modification of an atom's/molecule's/particle's lifetime and spontaneous emission spectrum compared to free space.
  • Casimir effect: The appearance of physical forces from the mode modification of the electromagnetic vacuum.
  • Vacuum Rabi splitting: The splitting of a resonant peak in the cavity spectrum due to interaction with a two-level system contained in the cavity (see Jaynes-Cummings-model).
  • Vacuum Rabi oscillations
  • Collective effects and superradiance: The modification of radiative and quantum properties by interaction of an ensemble of atoms/molecules/particles via the cavity field.

Models and Methods

Experimental platforms

Experimental platforms include (but are not limited to)

112 questions
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What are the "strong", "ultrastrong" and "deep strong" coupling regimes of the Rabi model?

The Rabi model describes a two-level system interacting via a linear coupling with a quantized harmonic oscillator, and it is described by the hamiltonian $$ H_{\rm{Rabi}}=\hbar\omega\, a^\dagger a +\hbar\omega_0\,\sigma_3+\hbar…
Emilio Pisanty
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What is QED about "Cavity QED"?

As I understand it, when papers and books refer to "Cavity QED" they simply mean the strong coupling regime of two-level system to a photon field in a resonator, i.e. Jaynes-Cummings and variants thereof. In other words, I could understand the whole…
Quasilattice
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What does it mean to Fourier transform a ladder operator (in the input-output formalism)?

I am currently trying to get my head around the input-output formalism. In describing the input-output formalism (link) , Gardiner and Collett take ladder operators in the Heisenberg picture and apply the Fourier transform to define the input…
asph
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Lindblad and Input-Output Formalism in Quantum Optics

I'm confused about how to apply the Lindblad formalism and the input-output formalism in practice, and how one goes between the two. Suppose I have a cavity (C) coupled to a reservoir (R), with the Hamiltonian governing the total system (C + R)…
Aegon
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Quantum input-output theory : Why do we multiply by density of mode to have a number of photon **per unit of time**

In this paper, https://journals.aps.org/pra/abstract/10.1103/PhysRevA.31.3761, we work with input-output theory. I will first summarize the physics of it and then ask my question. In input-output theory we model everything by saying : I send an…
StarBucK
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Does the Casimir effect allow to change the lifetime of a radiating atom?

Is it true that a spontaneously light-emitting atom changes its lifetime if it is put between two parallel plates that are so near that they attract each other through the Casimir effect? Thus: does the Casimir effect, and the changes in the vacuum…
user3148
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Rotating wave approximation and conservation of energy

So in my understanding, the RWA allows us to neglect terms that go as $e^{i(\omega+\omega_0)t}$ in an interaction Hamiltonian because if $\omega+\omega_0>>\omega_r$ where $\omega_r$ is the resonance frequency of the relevant interaction then the…
Cody Payne
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Classical limit of coherent state in Jaynes-Cummings model

Im dealing with an exercise on the Jaynes-Cummings model in a resonant single-mode approximation. The interaction Hamiltonian in rotating wave approximation is $$H_{int}=g\, \sigma_+\,a\,+g^*\,\sigma_-\,a^\dagger \tag{I}$$ where $a$ and $a^\dagger$…
curio
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Partition Function for the Jaynes-Cummings Hamiltonian

I was wondering if anyone here has calculated before the partition function for the Jaynes-Cummings Hamiltonian: $H_{JC}=\omega_0 (a^\dagger a + \sigma^+ \sigma^-)+g (a \sigma^+ +a^\dagger \sigma^-)$ (Here I have assumed resonance and $a,a^\dagger$…
Nicolás Quesada
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Collapse and revival in the Jaynes Cummings model

I'm having some trouble understanding the exact details of the collapse and revival in the Jaynes Cummings model. What I understand is this: We assume our two level atom to initially be in the excited state, interacting with a single field mode in…
user129412
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Why is the limit to observe quantum phenomena $k_B T < \hbar \omega_0$ in cavity QED?

In cavity QED you have to cool down the appartus so that quantum effects may be observed in a way that $k_B T << \hbar \omega_0$. I suppose that $\omega_0$ here means the frequency which the cavity doesn't suppress and the frequency equvivalent to…
user3237992
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It doesn't seem like energy is conserved for "input-output theory" of a cavity

For a long time I have struggled to make sense of "input-output theory." And unfortunately, I still cannot make any intuitive sense out of it. The key equation (found in this famous resource) is this boundary condition $$ \alpha_\text{out}(t) =…
Steven Sagona
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Rabi Hamiltonian with three instead of two Pauli matrices

This question was motivated by a question on Mathoverflow, in which a Hamiltonian is considered that looks like the Rabi Hamiltonian, but with three instead of two Pauli matrices: $$H=\omega a^\dagger…
Carlo Beenakker
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Adding a drive term on the Hamiltonian

The Hamiltonian of a optomechanical cavity driven by a laser of frequency $\omega_L$ is of the following: $$H = \hbar\omega_{cav}\hat{a}^{\dagger}\hat{a} + \hbar\Omega_{m}\hat{b}^{\dagger}\hat{b} - \hbar…
Pedro Pinho
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Coherent drive Hamiltonian

Sometimes in the light-matter interaction described by the Jaynes-Cummingsa model, an additional coherent drive is included which drives the light in the cavity. I've encountered this so many times in various quantum optics papers, but I still don't…
TheDorkSide
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