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

learn more… | top users | synonyms

1
vote
2answers
166 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 anti-...
0
votes
0answers
19 views

Is the truncated Wigner method efficiently classical simulatable?

The continuous-variable Gottesman-knill theorem says that the operation which varying the initial state described as the gaussian function (such as vacuum) to the final state described as the gaussian ...
0
votes
1answer
36 views

Are there any other tests demonstrating wave properties besides interference and diffraction?

Are there any other tests demonstrating wave properties besides interference and diffraction? How about refraction? Does it show wave properties also?
0
votes
1answer
64 views

Time multiplexed detector - pulse dispersion - foruier limits.

I'm currently in my second semester in physics and a couple of weeks ago I saw a job offer in the optics department of my university. Although I don't know much about optics, since we didn't deal with ...
2
votes
2answers
154 views

Entanglement of coherent states

I am new to quantum optics and I am trying to understand whether coherent states of the field could be entangled. Let's consider, for example, a two-mode state: $|\psi^{AB} \rangle = \frac{1}{c} \...
3
votes
1answer
143 views

Electron momentum distribution and wavefunction in momentum space

Does there exist any relationship between the electron momentum distribution used in above threshold ionization and the wave function in momentum space? In other words, starting with the wavefunction ...
4
votes
4answers
268 views

Are photons inside the media massive? If yes, why there is no Meissner effect?

We all know in vacuum travels with speed $c$, hence its rest mass has to be 0. In the media the light speed $v<c$. Then the photon renormalized by the medium (call it "quasi-photon" if you like), ...
11
votes
1answer
352 views

Which qubit states are accessible with linear optics operations?

Given a quantum state of $n$ qubits, and being restricted to linear optics (that is, the output annihilation operators are linear combinations of the input annihilation operators): Which states are ...
5
votes
1answer
492 views

Output of a beamsplitter with photon number (Fock) state inputs

Given a beamsplitter drawn below, where $\hat{a}$ and $\hat{b}$ are input modal annihilation operators, transmissivity is $\tau\in[0,1]$, and output modal annihilation operators are $\hat{c}=\sqrt{\...
0
votes
0answers
38 views

Is there a theoretical derivation of Kim's delayed choice quantum eraser?

Is there a theoretical derivation of Kim's delayed choice quantum eraser? The original paper only shows the experimental data.
0
votes
0answers
115 views

Gain clamping and threshold gain in quantum optics

We increase the pump power of a laser to the point where laser action starts, i.e. the threshold gain is reached. Now we increase the pump power even more, which increases the intensity of the cavity ...
3
votes
3answers
182 views

'size' of a photon

What's the smallest apperture a photon can pass through? I mean with no transmission at all. I'm pretty sure I saw long ago an experiment when they were reducing the size of a hole in a gold film and ...
2
votes
1answer
687 views

Obtain the Lagrangian from the system of coupled equation [closed]

In this particular paper, "Interaction between a moving mirror and radiation pressure: A Hamiltonian formulation" by C.K.Law, PhysRevA.51.2537 \begin{equation} \ddot{Q}_{k}=-\omega^{2}_{k}Q_{k}+2\...
3
votes
1answer
120 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 ...
7
votes
2answers
380 views

Are Rabi oscillations a pure quantum process?

Rabi oscillations are commonly known as the oscillations in time of the occupation probability of a quantum two-level system under the action of a coupling interaction between the two-levels. ...
0
votes
0answers
28 views

In Rayleigh's criterion, why does length not figure in the minimum achievable resolution?

For an $n$ slitted grating, Rayleigh's criterion is given by: $\frac{\Delta \lambda}{\lambda} = \frac{1}{Nm}$ (*) When I imagine two lightwaves of slightly different wavelength being shown through ...
0
votes
1answer
50 views

Verdet Constant and optical pumping

While studying Faraday rotation (linear magneto-optic rotation) I came across a fact that Faraday rotation can be enhanced. Verdet constant which depends on the wavelength can be enhanced as change in ...
2
votes
1answer
236 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 ...
4
votes
4answers
890 views

Why does optical pumping of Rubidium require presence of magnetic field?

The optical pumping experiment of Rubidium requires the presence of magnetic field, but I don't understand why. The basic principle of pumping is that the selection rule forbids transition from $m_F=...
0
votes
2answers
74 views

Light (Laser) operated optical switch

I have searched the web and found that optical switches are activated either through mechanical or electro/magnetics. Making them sort of Optomechanical or optoelectronic switches. Lets exclude ...
0
votes
0answers
33 views

Are the produced entangled photons in type II SPDC always in phase?

Are the produced entangled photons in type II SPDC (spontaneous parametric down conversion) always in phase? In Kim's delayed choice quantum eraser, two entangled photons are produced by a BBQ ...
0
votes
0answers
32 views

Is the master equation appropriate for a single system?

The master equation (Lindblad equation) describes the evolution of the density matrix of a system. Since it is a density matrix, so inherently, it describes an ensemble instead of a single system? In ...
2
votes
2answers
82 views

Silicon Laser and Laser mirrors

If I will place Silicon as the active medium to create a Silicon Laser. Why I cannot achieve Lasing ? secondly, why do we always consider Laser mirrors in an standing position along the optical axis ...
0
votes
2answers
115 views

Thought experiment on light accumulation

Consider an object which is a spherical one-way mirror, and let's call it the "Sphere". For the needs of the thought experiment, suppose that: the Sphere is perfectly spherical the mirror is ...
0
votes
1answer
73 views

Quantum correlation functions of the electric field

the first order correlation function for one mode (up to normalization) is definied as: $$g^{(1)}=\langle a^\dagger(t) a(t+\tau) \rangle$$ The second order: $$g^{(1)}= \langle a^\dagger(t)a^\dagger(...
0
votes
1answer
54 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 &...
1
vote
0answers
57 views

Ramsey pulse versus optical pumping: what's the difference?

A Ramsey pulse is a coherent process, where the electronic states of for example an ion (or some other two-level-system) are coupled to a laser field. By tuning the laser precisely, we can coherently ...
1
vote
1answer
77 views

What degrees of freedom (other than polarization) of a photon can be used to store quantum information? [duplicate]

Usually in quantum optics, one uses the polarization degree of freedom of the photon to create and manipulate photonic qubits. This, using various linear optics devices, can be coupled with the 'path ...
0
votes
0answers
45 views

The Longest Storage Time of Electromagnetically-Induced-Transparency-Based Quantum Memory

Do anyone know any paper that demonstrate the longest storage time of quantum memories protocol based on EIT achieved experimentally? I have tried to look for it on Google but find nothing.
0
votes
1answer
113 views

How to Derive Atomic Hamiltonian and Cavity Hamiltonian?

In a Fundamental of Quantum Optics and Quantum Information book which I am reading, it states without explanation that, in a two-level atomic configuration in a cavity system, the Atomic ...
1
vote
0answers
38 views

Recommended books that describe emission and absorption of light and light/matter interactions

Hello I am a Chemical Engineer that has ventured into the field of optics and I was wondering if there is any recommended book/books to understand the maths and also some answered exercises or ...
2
votes
1answer
60 views

Determining path of light through a nanolens

In the case of light passing through stacked liquids, we can use a ray approximation of the path of light to determine the path taken through each layer of liquid using Snell's law. From all the ...
3
votes
1answer
118 views

What is the meaning of coherent decay rate and population decay rate?

In quantum optics, especially the part when talking about atom-light interaction, there are two different kinds of decay rate, coherent decay rate $\gamma_{ij}$ where $i$ and $j$ are atomic energy ...
2
votes
0answers
93 views

Quantum optical master equation

In Quantum Noise by Gardiner and Zoller (p. 86f) they derive and write a version of the quantum optical master equation. $ \dot{\rho}_S (t) = -\frac{i}{\hbar} [H_\mathrm{sys} ,\rho_S] - \sum_m \frac{...
1
vote
0answers
88 views

Creating an arbitrary state of the quantum simple harmonic oscillator

Suppose $\mathcal{B}=\{|0\rangle, |1\rangle, |2\rangle, ... \}$ is the energy eigen-basis of a quantum simple harmonic oscillator. I want to create the state \begin{equation} |\Psi\rangle = c_{0}|0\...
1
vote
1answer
90 views

Mach-Zehnder interferometry wave functions

Consider the set up below: I have read that in the apparatus the wavefunction is given by: $$|\psi \rangle=e^{i\theta}|c \rangle +i |b \rangle$$ where $\theta$ is the phase added by the phase adder....
1
vote
1answer
61 views

Superscript on density matrix

I have been asked in homework to solve the optical bloch equation for the initial condition of $\rho_{22}=0,\rho_{12}=0$. Professor gave a hint of the general equation and let us carry it from here. ...
1
vote
1answer
73 views

Does spontaneous emission actually emit in a random direction, or is it measured in a random direction?

When an excited state couples to the vacuum, it has an infinite number of directions of the quantized electromagnetic field to couple to. Does it evolve into a superposition of all those directions at ...
0
votes
1answer
59 views

Quantum beam-splitter matrix

I have seen the matrix for the action on a quantum beam splitter described in one of two ways: $$\begin{pmatrix} t_1 & r_2 \\ r_1 & t_2 \end{pmatrix}$$ (this appears in Quantum Optics by ...
6
votes
3answers
215 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 ...
1
vote
0answers
25 views

decoherency of number states

The meaning of decoherency is: When a nonclassical state, transitions to a classical state. It means that the state lost it's phase information. I can't understand how it happens in number states.
0
votes
0answers
31 views

Is local oscillator light polarised?

If a laser is used as a local oscillator in the homodyne setup does this mean the light it produces is polarised? (I am looking at this from the context of quantum physics and random number generators,...
0
votes
1answer
122 views

I want to solve Mathieu Equation $y''(x)+(a−2q \cos(2x))y(x)=0$. How to solve it using Floquet solution?

I want to solve Mathieu Equation $$y''(x)+(a−2q \cos(2x)) \, y(x)=0.$$ How to solve it using Floquet solution? In Floquet solution for integer order of $v$ and $π$ periodicity We have Solution $$y(x)=\...
4
votes
1answer
264 views

Do Bell inequality violations appear instantly when the source is turned on, or do they increase over time?

This experimental Question is a result of reading a particular article on Bell violations. I addressed the e-mail below to the corresponding authors —because who knows, they might reply— but it is not ...
0
votes
1answer
53 views

Oberving a photon through double slits

If we send a particle with mass through the double slits we observe a interference pattern. That is of course if we don't observe which slit the particle goes through. If we do then we get two peaks ...
0
votes
1answer
63 views

Colour of certain objects

How do internal structural bandgaps define object colour? For example, if an object is transparent, are the energy bandgaps in the structure too large for even the 400 nanometer photon to be able to ...
2
votes
1answer
1k views

Stark effect in two level atomic, laser-driven system?

In a two level atomic system (Rabi oscillating problem) the perturbative potential is oscillating / sinusoidal because it comes from the electric field from the laser. Now stark effect is the ...
3
votes
1answer
149 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 ...
4
votes
1answer
360 views

What is the difference between QED and quantum optics?

What is the difference between QED and quantum optics? Once you have QED, you have not only the quantized EM field, but also the interaction between matter and the EM field. So, you should have ...
1
vote
0answers
53 views

In the photon picture, how can light slow down and yet not be absorbed? [duplicate]

Many materials, such as glass, are transparent over some wavelength interval. In the photon picture, as far as I understand it, this is because there are no allowed transitions corresponding to the ...