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Questions tagged [cavity-qed]

Cavity QED is the study of quantum effects in resonant cavities, enhancing the interaction between light and matter.

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Do quantum error correction codes depend on the type of quantum computation (circuit QED/topological/etc)?

So I know that there are different types of quantum computation that can be realized (cQED, topological quantum computation among others), and different error correction codes that exist. Naively I ...
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Cavity optomechanics Hamiltonian

In cavity optomechanics the radiation pressure exerted by light moves a mirror in a cavity. Because of that the resonance frequency of the cavity changes due to change in length of the cavity (cavity ...
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What is the difference between a harmonic oscillator and a cavity mode?

this question might seem ridiculous to you, but I will really appreciate it if you could clarify the difference between a harmonic oscillator mode and a cavity mode. Below is my depiction. For a ...
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Resonant frequency shift for cavity superconducting circuits

For superconducting circuits coupled to a resonator, we get a shift in the transmission spectrum (vacuum Rabi splitting) because of the interaction of the qubit and the resonator. Then one goes to ...
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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 resonat single mode approximation. The interaction Hamiltonian in rotating wave approximation is $$H_{int}=g\, \sigma_+\,a\,+g^*\,\sigma_-...
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73 views

Why does Jaynes Cummings not describe an atom in free space?

I'm a bit confused about the application of the Jaynes Cummings model and what exactly is meant by "one single mode": Usually, it is said that the Jaynes Cummings model describes a single atom in a ...
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Ring cavity mode approximation

I'm interested in modelling electric field operator of an ellipsoidal nanoparticle quantum mechanically. After some research, I found that we can approximate field arising from a spherical ...
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What is a mode? Regarding electromagnetic waves in a closed cavity

This concept is very unclear to me, and the more different sources I find, the more contradicting definitions and explanations I stumble upon. Let's use this source as a basis for my question: http://...
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111 views

Is the total number of excitation conserved with Rabi Hamiltonian?

From quantum optics textbooks, I have learned about Jaynes-Cummings Hamiltonian for a description of atom and field interaction, as an approximated model under the so-called rotating wave ...
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Is there a limit to photon density? [duplicate]

Photons are bosons so, in principle, they are perfectly happy to exist together in the same state. But is there a limit on how many can exists in a finte volume? Does QED or vacuum breakdown ...
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59 views

Spectrum from cavity radiators

A hole in a cavity kept at a constant temperature is supposed to approximate the behaviour of a black body. If an external heat source is keeping the body at a constant temperature wouldn't the heat ...
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71 views

Dependence of Rabi oscillations on laser power

Is there an expression for the dependence of the Rabi oscillations of a system on the laser power? The system I'm considering is an electron spin in a quantum dot.
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Electric field operator of an ellipsoidal metal nanoparticle

I learnt from a publication (https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.105.263601) that the positive frequency component of a spherical metal nanoparticle can be written as $\hat{E}^+...
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208 views

Hamiltonian for single-mode field in cavity

Given that the Hamiltonian for a single-mode field is $$ H = \frac{1}{2}\int dV \left[ \epsilon_0E_x^2(z,t) + \mu_0^{-1}B_y^2(z,t) \right],$$ with \begin{align} E_x(z,t) =& \sqrt{\frac{2\omega^2}{...
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Obtaining equations of motion for a three-level atom and plasmon system

I am interested in a scenario where a three level atom (cascade/ladder type) is interacting with a spherical metal nanoparticle (MNP) with single plasmonic excitations. Let us assume that the ground, ...
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478 views

Quantization of single mode field in a cavity

I am studying quantum optics from Gerry and Knight's book. This question has to do with section 2.1 of the book, where a single mode light field in a cavity is quantized. The formal equivalence of a ...
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57 views

Eigenmodes in a Ring resonator made of 4 Mirrors

Let's assume a Ring Resonator, consisting of 4 mirrors that are 100% reflective, that are arranged in a square with lengh $L$. What properties would the eigenmodes of the cavity have? Would it be ...
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59 views

Actual classical time evolution in a closed Cavity

I'm stuck with the question how the actual time evolution of a given classical electric field in a closed cavity will look like. The initial conditions are a given function $u(x)$ in a one ...
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Cavity quantum electrodynamics: difference between Rabi oscillations and vacuum Rabi oscillations?

I believe the title is pretty self-explanatory: I understand both roughly, but am unable to make a clear distinction. We use a circuit formulation for which an LC circuit, being a resonator, is the ...
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Why are the normal modes in a CQED system centered around the dipole frequency instead of offset like in a classical coupled oscillator system?

I am trying to understand the modified spontaneous emission spectrum from a dipole coupled to a cavity mode in terms of a classical coupled oscillator system. The usual analogy made in a lot of CQED (...
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106 views

In cavity optomechanics, what does it mean that a cavity mode is driven by a classical field?

What do we mean by the statement when we say that a cavity mode is driven by a classical field or classically controlled field, in Cavity Optomechanics?
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How do I derive and use the effective hamiltonian for plasmon-exciton coupled system to obtain operator equations of motion?

Consider the interaction of a single surface plasmon mode in a metal nanoparticle with a dipole emitter(atom) under the classical driving field $ E_i = E_0e^{-i\omega t} + c.c $ , with the following ...
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Deriving coupled equations of motion using optical master equation for atom-plasmon system

I am learning the interaction between surface plasmons (which are bosons that act much like photons) and atoms. I came across the following scenario describing the interaction between a two level ...
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What a single mode optical resonator? [closed]

This is a term from cavity quantum electrodynamics. I want to know whether the wavelength can be different when the mode is on: one of $d$ , $d/2$, ...., $d/n$ or is it always equal to $d$. Also how ...
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Change in Q factor on tuning external magnetic field in Electron spin resonance experiment

Does the Q factor of the cavity resonator show a dip at the resonant value of the external magnetic field while performing an ESR experiment?If so, what is the physical reason behind it?
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Role of Cavity Resonators in continuous wavelength-electron paramagnetic resonance(CW-EPR)

Why is it necessary to place the sample in a cavity resonator for obtaining EPR spectrum in CW-EPR? What role does a cavity resonator play in a CW-EPR spectrometer?
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153 views

How to experimentally create an atom in a superposition of ground and excited states? [closed]

For Quantum Computing we use atoms in superposed states, but how do we physically create them?
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How does the electric field operator change inside an optical cavity

In the free field, transverse electric field operator is given by the below expression; $$d^{\bot}(R)=i \sum_{p,\lambda}\Big( \frac{\hbar cq}{2V\epsilon_{0}}\Big)^{1/2} \{e^{(\lambda)}(p)a^{(\lambda)}...
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Why is the frequency bandwidth of the environment important for Markovianity?

In the derivation of Spontaneous Emission in two level systems in Quantum Optics (be it Wigner Weisskopf or a different approach, such as density operators to find the master equation), one makes (...
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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 ...
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155 views

Introducing time-dependent drive into the Hamiltonian of quantised electric circuits

Suppose I have the schematic of a superconducting electric circuit composed of (quasi) lossless linear inductances and capacitances and some non-linear inductances, eg. Josephson junctions. The ...
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1answer
294 views

Commutation of field and atomic ladder operators in the Dicke model

Consider the Dicke model, whose Hamiltonian is (in the rotating wave approximation) \begin{equation} \hat H=\omega_c \hat a^\dagger \hat a+\omega_0 \hat \sigma_z + g(\hat a^\dagger \hat \sigma + \hat ...
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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 ...
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spread of fock state distribution and infinite revival time of rabi oscillation in spontaneous emission

In cavity QED for a 2-level atom, the revival time for oscillation b/w the states $\left|\ e\ 0\right\rangle$ and $\left|\ g\ 1\right\rangle$ (absorbing the same photon that is emitted) is said to be ...
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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 +\...
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108 views

How is a qubit realized in a cavity?

Considering a single photon in a cavity, how is a qubit realized in this setup? How is the qubit $|0\rangle$ or $|1\rangle$ manipulated? I.e. how are the transitions $|0\rangle \to |1\rangle$ and $|1\...
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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: $H_{JC}=\omega_0 (a^\dagger a + \sigma^+ \sigma^-)+g (a \sigma^+ +a^\dagger \sigma^-)$ (...
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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 ...