A research field within general optical physics concerned with light and its material interaction: where light is modelled by full quantum mechanical description.

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Single particle passing through the double slit at a time

In modern experiments, With the classical setup of photons or electrons passing through double slit, the intensity is kept extremely low, such that one can detect a single particle passing through ...
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37 views

What is the difference between Fermi golden rule and Wigner-Weisskopf theory?

What is the difference between Fermi golden rule and Wigner-Weisskopf theory? They both deal with the spontaneous emission process. So what is the difference? As far as I know, the fermi golden rule ...
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37 views

Time that we have changing color [closed]

I have a question but I don't know the answers and the book or sth else for answering to it : Please help me and tell me anything When do we have a color changing in clothes when they get wet?
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1answer
44 views

Do photons emitted from a LED show bunching?

If photons are emitted from a thermal source, we get photon bunching. For coherent radiation, the detection probability doesn't change after detecting a photon. For single photon sources, we get ...
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2answers
35 views

When was Electromagnetically Induced Transparency first introduced?

The oldest paper I know regarding this topic was published in 1997 by Stephen E. Harris. But I am not sure if he is the first to introduce this idea. Could you tell me when and by who did introduce ...
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27 views

Any suggestion of laser pointer for everyday life study of fluorescence?

I want to buy a laser pointer to study fluorescence in my kitchen. Any suggestion? What kind of laser pointer? What stuff for demonstration?
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23 views

Why the plots of a second-order intensity correlation function appear both Bunching and Antibunching?

This second-order correlation function is calculated based on a single atom in a cavity, driven by classical light source,under the condition of two photons resonance. When I plotted it in ...
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21 views

Classical and semi-classical vs quantum interferometry

What is the difference between classical, semi-classical and quantum interferometry? How the detectors look like? As far as I know in classical interferometry light is treated as a wave, whereas in ...
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20 views

Refractive index for matter waves

What is the relation for a group velocity of matter waves with refractive index of general medium? Google will tell you the answer but majority of them are related to experimental work for a specific ...
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2answers
41 views

How many photons are absorbed during Rabi oscillations?

In my understanding, Rabi oscillations are derived using the classical approximation for the electromagnetic field. I don't get how this picture fits with a quantized EM field though. Say you excite a ...
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1answer
69 views

Time-dependence of ladder operators in quantized EM fields

My Question Are the operators for the $A$, $E$ and $B$ field to be treated as operators in a Heisenberg description or is their time dependence explicit when performing a textbook EM quantization as ...
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1answer
37 views

Phase shift of the displacement operator

According to my professor, the displacement operator $D(α)=e^{\alpha a^†−α^*a}$ can be written, "with a simple phase shift", as $D(α)=e^{i\alpha(a^†+a)}$ which he then proceeds to write as ...
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1answer
60 views

How does a laser emit light in a coherent state?

Lasers work by stimulated emission of atomic transitions. Stimulated emission produces two photons which, because the particle number is well-defined, projects the field into a Fock state. However, it ...
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31 views

Are the Wigner and Husimi transforms injective?

I am wondering if the Wigner function is injective. By injective I mean, that, for every density matrix $\rho$, there is a different Wigner distribution. The same question applies to the Husimi ...
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1answer
90 views

How can a photon have a frequency but not a phase?

When a single photon is emitted as a result of relaxation of an electronic energy level, it (the field) is clearly in a Fock state because it has a well-defined number of quanta. By the uncertainty ...
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1answer
26 views

doppler cooling temperature limit

Wikipedia shows a heating effect that causes minimum temperature achievable in doppler cooling as: "The atom performs a random walk in momentum space with steps equal to the photon momentum due to ...
3
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1answer
44 views

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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87 views

Group theory and quantum optics

This is a question about application of group theory to physics. The starting point is the group $SU(n)$. I have a representation $R$ of $SU(n)$ that takes values on the unitary group on an infinite ...
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1answer
126 views

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 ...
2
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26 views

Thomson scattering on the elections does not produce any circular polarization?

All references on CMB polarization has this statement as if it is a trivial fact. But I have to admit that I completely don't understand what this sentence is telling us.
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78 views

how to arrive at first-order correlation function with the above master equation?

My question arose when I was reading a paper called " Multi-photon Blockade of the dressing of the dressed states'. This is the states this paper used: This is the master equation this paper has ...
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2answers
121 views

How to connect Rabi frequency with absorption intensity?

If a particle with non-degenerate spectrum starts in some eigenstate, and the frequency of the external EM field matches some transition frequency, then this would lead the particle to do periodic ...
3
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2answers
84 views

Is $\phi_n =\left\langle \vec r | n \right\rangle $ the photon wave function?

I am a bit confused about this issue and I am still not clear whether is there is a photon wave function or not. Since we use Fock states $| n \rangle$ to represent the state of a quantized ...
3
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1answer
100 views

Phase noise and linewidth of laser

I learned that the linewidth of a single frequency laser is closely related to the phase noise. But this sentence from a book completely confuses me: "A quantum-limited beam in a so-called coherent ...
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33 views

Jaynes-Cummings Model in Quantum Optics

Why doesn't JC model remain valid under the weak atom-field coupling?
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3answers
116 views

How far back can you trace a photon?

You have a photomultiplier tube pointed at a distant star, exactly 100 light years away. It's perfectly set up so that nothing can get into the tube unless it came from that star. Every hour or so, ...
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2answers
47 views

Can a two-levels photon pair be created either entangled or not entangled? [closed]

I am learning about experiments on Quantum Optics and Quantum Tomography in order to understand how to measure two qubits with an arbitrary quantum state of their polarization degrees of freedom. ...
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1answer
57 views

Density matrix of a single qubit as a function of its Stokes Parameters

$\newcommand{\bra}[1]{\left\langle#1\right|} \newcommand{\ket}[1]{\left|#1\right\rangle} \newcommand{\prom}[1]{\langle{#1}\rangle} \newcommand{\matrixel}[3]{\bra{#1}{#2}\ket{#3}}$ How can I prove ...
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1answer
55 views

Calculating a resonance fluorescence spectrum (Mollow Triplet)

I was working through a lecture on quantum optics, in which we calculate the spectrum of electric field correlations of fields produced by two level emitters. Now, the part where I got stuck was ...
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2answers
42 views

Structure of white light? [duplicate]

White light is a mixture of different wavelengths. If so what will be the structure of a beam of white light ? Is there a separation between different colours ? what does it actually mean ? Does a ...
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2answers
118 views

Describing a single photon with creation and annihilation operators

Since I am not fully aware of the creation and annihilation operator formalism for single photons, I want to ask, if the following is correct: I am considering a photon in the vacuum which travel ...
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25 views

Rationale for definition of input/output operators in quantum langevin equations

I am going through Gardiner & Zoller's 'Quantum Noise', and following the derivation of the Langevin equations in terms of input/output operators. Let the bath Hamiltonian be: ...
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3answers
296 views

How noisy are photon detectors?

I have a single photon detector and $N$ photons per second arrive at the detector. Then something happens and the number of incoming photons per second changes by the factor of $\alpha$. So now ...
2
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1answer
52 views

Single photon pulse and its electromagnet field

I describe the temporal distribution of a single photon pulse in an interferometer experiment in vacuum via the Gaussian function $\psi$: $$ \psi(t) = \tfrac{1}{(2\pi\sigma^2)^{1/4}} \text ...
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2answers
40 views

Lowest detectable power of a laser?

What is the lowest power of a laser beam which is still detectable? More precise: If the intensity of my laser beam is reduced by a factor of $10^{-8}$, can I still detect it? Of course this depends ...
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49 views

How to represent a laser pulse in quantum optics

Every quantum optics textbook that I've found says something like "a coherent state represents the output of a laser", but a coherent state is a static thing (aside from the oscillating phase of the ...
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2answers
47 views

How to construct matrix to apply U(2) beam splitter to a N dimentional Beam

So I am trying to read this paper (no paywall here). In this the formal construction of a matrix $T$ is given as The product of matrices is equivalent to setting up experimental devices in ...
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25 views

(Optical) Coherent states being all orders coherent

I recently read that coherent states $|{\alpha}\rangle = e^{-|\alpha|^2/2} \sum_{n=0}^\infty{\frac{\alpha^n}{\sqrt{n!}}|{n}\rangle }$ are all orders coherent, according to the definitions given on ...
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1answer
41 views

Why does an external laser drive only couples certain levels?

I was always wondering how is it that all the quantum optics levels schemes are depicted as if the laser couples only two certain levels with some frequency. For exmaple the standard lambda system ...
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32 views

Flip of polarisation of light

Consider an optical experiment with photons or light pulses. Is there an optical element that acts in the polarisation degree of freedom like the unitary $$ U = \frac 1 {\sqrt 2} \begin{pmatrix} 1 ...
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1answer
113 views

Mirror that flips polarisation?

Is it possible to build a mirror which not just reflects a photon but also flips its polarisation from horizontal tho vertical (or vice versa)? The reason why I ask is the following: If I put an ...
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19 views

What is meant by spatially multimode states of light?

I came across this term while reading texts on Quantum Optics and Lasers. While I know something about multimode laser oscillations, I am unsure about what is exactly meant by multimode light?
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1answer
217 views

What is the difference between correlation and entanglement?

I have read that not all correlated states are entangled. What is the difference between the two? Mathematically, it was stated that a system which can be put in the form of ...
3
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2answers
187 views

What does $g^{(2)}$ signify in quantum optics? And how to calculate it?

I have been studying research papers on Quantum Optics and non-linear optics. I frequently come across the $g^{(2)}$ value. What does it signify? What is its importance? How to calculate it? And ...
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45 views

Optical pumping, Breit-Rabi equation, how to get hyperfine energies?

I'm working on a lab report for a lab on optical pumping using Rb, but I'm seriously struggling with figuring out how to get the hyperfine energies through the Breit-Rabi equation: ...
2
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1answer
65 views

What are the 'types' of parametric down conversion?

I'm looking at photon entanglement, and everywhere in the literature there's a reference to 'type-II' parametric down conversion as a source of entangled photon pairs. I know what parametric down ...
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36 views

Dipole Moment of Collection of Harmonic Oscillators [closed]

I am given the Hamiltonian of a collection of SHO with resonant frequencies $\omega_{n1}$ $$H = \sum_n\hbar\omega_{n1}[a_n^\dagger a_n+\frac12+\alpha_nE_0\cos(\omega t)(a_n+a_n^\dagger)]$$ Where ...
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189 views

Definition of spatial and temporal coherence in QM?

It is often said that lasers are spatially and temporally coherent. Is there a simple definition of spatial and temporal coherence in the language of quantum mechanics? More specifically, can these be ...
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82 views

A quantum mechanical description of a polarizing filter

When a single photon with polarization $\mathbf{a}$ arrives at a linear polarizing filter in the direction $\mathbf{p}$, the photon has a probability of $(\mathbf{a}\cdot\mathbf{p})^2$ to pass through ...
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Spontaneous parametric down conversion and relative time of emission of two entangled photons

A pump beam excites a non-linear crystal which produces two entangled photons with perpendicular polarization, namely in the state $|HV>+|VH>$. Are there examples where one of the photons was ...