Questions tagged [rabi-model]
40 questions
16
votes
1 answer
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
- 137,480
8
votes
1 answer
Intuitive explanation for Rabi oscillations in a two-level system
Is there an intuitive explanation of why the Rabi oscillations with frequency $\Omega$ occur in a two-level systemand why they get faster when the transition dipole moment $M$ ($M\propto V$) gets larger or/and when the frequency of the light…
peter mafai
- 451
6
votes
2 answers
General Two-State Systems and Rabi Oscillations
I've been working on this for quite a while now and can't seem to figure it out. I am concerned with the dynamics of a general two-state system, specifically the case of a particle in a constant magnetic field coupled with a time dependent magnetic…
Josh Pilipovsky
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5
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Two photons Rabi oscillation
Assuming we have a 2 level system (e.g. an atom with 2 energy levels) and the lifetime of the upper level can be neglected, if we make the atom interact with a laser at a fixed frequency, we would get Rabi oscillations (assume the laser is on…
JohnDoe122
- 673
5
votes
2 answers
Two Level Atom Rotating Frame
Introduction
I am trying to work out the Rabi problem. In particular I am trying to work it out from a perspective focusing on the operators rather than the kets. Think Heisenberg picture rather than Schrodinger picture. It's a bit tricky because in…
Jagerber48
- 16,234
5
votes
2 answers
Violation of energy conservation by counter-rotating terms in Rabi model for atom-field interaction
When we describe the interaction between two-level atom and single-mode electromagnetic field in quantum optics, we have the so-called Rabi-model before the rotating-wave approximation, by which the Rabi-model becomes the Jaynes-Cummings model. In…
Veteran
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4
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1 answer
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
- 486
4
votes
2 answers
Rabi Oscillations: $\pi$-Pulse vs a single photon
I am puzzled by the following:
Assume an atom as a two-level-system.
A $\pi$-Pulse acting on an atom in the ground state promotes this atom in the excited state. This is done by a continuous electromagnetic wave over a certain amount of time, such…
Welcome_Green
- 479
4
votes
1 answer
How does "coherence" contribute to inverting a two-level system?
In laser physics I am told that inverting a two-level system is not possible, since it will become transparent once the inversion reaches 50% and no longer be able to absorb more photons. This makes it impossible to create a laser using two-level…
HerpDerpington
- 975
3
votes
1 answer
Fine-structure constant, coupling strength and their experimental manifestation in the field of light-matter interaction
I am currently studying the quantum Rabi model, whose Hamiltonian reads
$$
H = \frac{\Omega}{2} \sigma_z + \hbar \omega a^\dagger a + g (a^\dagger+a) \sigma_x.
$$
In mainstream papers, this is the Hamiltonian we work with. However, I am asked the…
Makita_Youki
- 61
3
votes
1 answer
Non-hermitian Hamiltonian $H^1(t)=H^1e^{−i\omega t}$ on Wikipedia page for Rabi problem
I read about the Rabi problem at Wikipedia, but there is something I don't understand. They introduce a periodic perturbation $$H^1(t)=H^1e^{−i\omega t}.$$ But isn't this hamiltonian non-hermitian? Specifically, the hermitian adjoint would look like…
Riemann
- 1,595
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3
votes
2 answers
Two different expressions for Rabi Frequency (on resonance)
I've been searching through several articles and books and I found two different expressions for the Rabi Frequency on the semiclassical rotating-wave approximation, and they are different by a factor of two.
Consider a eletric field…
2
votes
0 answers
Blue/Red Detuning - AMO Physics
When detuning doesn't equal 0, meaning frequency of light doesn't equal the frequency of the atom oscillating (when dealing with 2 level systems), we see there are light shifts as a result. In the large detuning limit, we can split this into two…
2
votes
1 answer
A problem with the analytic solution to Rabi oscillation of a two-level system
Rabi oscillation of a two-level system is colloquially discussed in textbooks about quantum mechanics (especially quantum optics), so I think I'm good with just stating the results.
The Hamiltonian is given…
hendlim
- 856
2
votes
0 answers
AC Stark shift in a 3 level system
If we have a 2 level system and I send a laser on resonance, when working in the dressed atom description, each level gets split by $\pm\Omega$ i.e. the Rabi frequency of the laser. Now if we send a second, probe laser, that laser will see a Mollow…
JohnDoe122
- 673