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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Understanding the relationship between Phase Space Distributions (Wigner vs Glauber-Sudarshan P vs Husimi Q)

I am moving into a new field and after thorough literature research need help appreciating what is out there. In the continuos variable formulation of optical state space. (Quantum mechanical/Optical)...
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Can DC electric field be regarded as a quantum harmonic oscillator? [duplicate]

The essence of quantum theory of the radiation field is the association of a quantum harmonic oscillator with each mode of the field. However, in the case of DC electric field, can we describe DC ...
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28 views

Wigner Function for Thermal State

I am currently doing a reading on the subject of Quantum Optics from the book "Quantum Optics by Marlan O.Scully and M.Suhail Zubairy", I am currently learning about Quasi Probability distributions. ...
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26 views

Energy loss of photons crossing a dielectric medium

How much energy do photons lose when crossing an "isotropic" dielectric medium? What would be possible mechanisms. I assume the straight forward answer would be that the photon loses zero energy and ...
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495 views

double slit experiment with two opposite quarter waveplates

Consider the usual double slit experiment involving laser and a double slit and a screen. Now place in front of the left slit a quarter waveplate (let's call it QWP1) that changes a certain linear ...
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50 views

Gravitational Lensing Example

Like this tomato wrapped underwater and how light is bent around it does the way a black whole bends space and light in the same way?
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What does phase shift represent in a Mach-Zehnder interferometer?

When describing the polarization of a photon, phase refers to the difference in the phases of the polarization components. E.g.: $|\psi\rangle$ = $|L\rangle$ + $i|R\rangle$ can be said to have a ...
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2answers
79 views

Meaning of non-degenerate photon pair

I am seeing in a lot of papers about quantum optics the term "non-degenerate photon pair", which seems like a very important concept. This may seem like a silly question, but I am an EE undergrad who ...
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1answer
27 views

What do the authors mean by “closing operator”?

I'm reading a paper titled "Luminescence spectra of quantum dots in microcavities II Fermions" (link). In section III, the authors introduce so-called closing operators. I don't have enough background ...
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1answer
608 views

Formula for Rabi frequency

The Rabi frequency is an expression of the light-matter interaction (Hamiltonian) and gives a relation between field polarization and electric dipole. Reading the book of Cohen-Tannoudji (Complement $...
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265 views

First order coherence through double slit

The state $$|\Psi \rangle = |0\rangle + \sum_j \int d\omega f_j(\omega)\hat{a}^\dagger_j (\omega) |0\rangle $$ is coming from a far field and incident on a double slit setup. Here j is the index of j-...
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127 views

Von Neumann entropy of mixtures of coherent states

I'm trying to calculate the Von Neumann entropy of statistical mixtures of coherent states. The problem is that such states are in general non-Gaussian, so one cannot follow the formalism developed ...
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37 views

How to find the covariance matrix after a partial homodyne measurement?

The Gaussian state of two modes, with quadrature operators $X_1,P_1,X_2,P_2$, is given by a displacement vector $d$ and covariance matrix $\sigma = \begin{bmatrix} Var(X_1,X1) & Var(X_1,P_1) &...
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Photons with half integer angular momentum - what's happening?

I have just read this article - what is happening? Analysing these beams within the theory of quantum mechanics they predicted that the angular momentum of the photon would be half-integer, and ...
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1answer
2k views

Explanation of the experiment with Mach–Zehnder interferometer (self-interference of a single photon)

Here is the description of experiment which uses Mach–Zehnder interferometer http://en.wikipedia.org/wiki/Mach%E2%80%93Zehnder_interferometer or http://departments.colgate.edu/physics/research/...
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How can I calculate the time domain correlation function in the frequency domain?

I have an operator $a(t)$, its correlation function is: $$<a(t)a^{\dagger}(t^{\prime})>=\delta(t-t^{\prime})$$ Now I need to find the correlation function in the frequency domain. i.e. to ...
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21 views

Bandwidth of second-harmonic generated (SHG) field for pulse excitation

I wanted to know the bandwidth of the second-harmonic field generated from type-I SHG process when excited with a pulse of bandwidth $\Gamma$. In this lecture notes, the author calculates the ...
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49 views

Physical Significance of Wigner Equation, Wigner Current

I am Currently doing a reading about Wigner function in Quantum optics, I learnt that the Wigner function maps the Quantum mechanical operators to phase space functions in phase space, so we can talk ...
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1answer
30 views

Parity conservation in second harmonic generation?

The second harmonic arises from susceptibility of third rank tensor $X^{(2)}$ which have (-1) parity. page 28 Let say two photons are absorbed and one is emitted, so the total change in parity is $(...
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1answer
50 views

Gaining some intuition: Photon bunching

This is a very easy question: I'm in need of some intuition on the fact that, e.g. thermal sources, produce bunched photons. It is very easy to "undertand", without any quantum mechanics, why single ...
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1answer
43 views

Is Mott insulator the same as non-compressible quantum fluid?

In the field of ultracold quantum gases we study the so called Bose-Hubbard model given in second quantization: $$\hat{\mathcal{H}} = -t\sum_{\langle i,j\rangle}\hat{a}^{\dagger}_{i}\hat{a}_{j} + \...
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1answer
31 views

Reaching equilibrium in a blackbody and light-matter interaction

Suppose we have a metallic cavity maintained at a fixed temperature. Suppose we start with any distribution of radiation that is not in equilibrium with the container. Gradually, when the equilibrium ...
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1answer
40 views

Rotating wave approximation for two coupled resonators and a drive

I'm having some trouble with what I think should be an easy calculation. On qutip.org/docs/2.2.0/examples/me/ex-25.html they calculate the steady state for a master equation, more specifically they ...
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22 views

How is the conversion from an operator equation to a c-number stocastic differential equation justified?

In many papers on laser dynamics theory, quantum Langevin equation of operators is converted to c-number stocastic differential equations, which is analyzed to obtain results. However, why this ...
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1answer
41 views

Difference between Amplitude and Intensity Interferometer?

A lot of books explain the first order and second order coherence correlations for light. They explain the difference between these using interferometers (Michelson and Hanbury-Brown and Twiss (HBT) ...
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43 views

Sech laser pulse time-bandwidth product calculation

Find the time bandwidth product for a $\operatorname{sech}$ shaped pulse. Attempt: I know that the time bandwidth product $\Delta t \Delta \omega$ for a $\operatorname{sech}$ shaped pulse must be $...
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65 views

Why probability of detection by performing unambiguous quantum measurement is less than random guess in mesoscopic quantum regime?

In mesoscopic quantum regime (mean photon number 10000) and non-orthogonal coherent state(number of non-orthogonal coherent state 2000), why probability of detection by performing quantum unambiguous ...
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Why probability of detection of optimum unambiguous discrimination between linearly independent symmetric states is less than random guess? [duplicate]

Considering the analysis and result of this paper, http://arxiv.org/pdf/quant-ph/9807023v1.pdf, I have used equation (3.15) and (4.3) to calculate the optimum probability of success for mean photon ...
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250 views

In quantum optics if you measure the energy of a thermal state does it collapse to a Fock state (Photon number state)?

As I understand it a thermal state is a state of light such that the light is in a superposition of many Fock states (Photon number states) with the probability of the light being found in a ...
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1answer
72 views

Representing operators in the Glauber-Sudarshan P-representation

If $| \alpha >$ represents a coherent state (the normalized right eigenstate of the destruction operator $a$ in Quantum Mechanics; $\alpha$ is a complex number), then it is known that: \begin{...
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3answers
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What causes atoms to have their specific colors?

I understand that light (color) is part of the electromagnetic spectrum, and that it depends on what wavelengths are reflected/absorbed. Though what property of an individual atom gives it its color? ...
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46 views

Second Order Coherence of NOON State

Given the entangled state $\vert NOON \rangle =\frac{1}{\sqrt{2}}(\vert N,0\rangle + \vert 0,N\rangle)$ how can the second order coherence function at time $\tau$ and 0 be calculated? I know that $g^{...
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35 views

Master equation approach only suitable for good cavity laser?

As I understand, master equation and quantum Langevin equation are equivalent formalisms. However, in a Review of Modern Physics article titled sub-Poissonian processes in quantum optics, the author ...
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Resonance Fluorescence spectrum of a symmetric state of two atoms

So recently I've learned about the fluorescence spectrum of an atom (say a two level system) driven by a laser close to its resonance frequency. You get a dressing of the atom states with the laser, ...
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1answer
87 views

What exactly happens when total internal reflection takes place at a quantum level?

What happens when light interacts with the boundary between 2 mediums at a quantum level? Why is it totally reflected back when it is travelling from an optically denser to a less dense medium? How ...
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1answer
59 views

How to transform a wigner function to represent loss of mode information (coarse graining)?

I have a highly multi-mode gaussian wigner function representing an optical field: $$W\left(\{p\},\{q\}\right)=\mathrm{Exp}\left(-\sum_{j=0}^{f}(b_{j}q^{2}_{j}+a_{j}p^{2}_{j})\right).$$ However the ...
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1answer
116 views

What is a quasi-probability distribution?

I have some questions about the quasi-probability distribution. What is it? And why it is important in quantum mechanics? And what does "quasi" mean?
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Lasing in a 2-Level system?

What exactly is the difference between 2-Level, 3-Level and 4-Level systems? Why can we not achieve stimulated emission in a two-level system using optical pumping?
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Beam Splitter: looking for a “not-typical” second quantization but full-quantum description

In all the books of Quantum Optics I read, the theory of beam-splitter (BS) is presented in more or less the same way, e.g. introduction of the transmission-reflection matrix, case study of the single ...
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43 views

What is the easiest way to prepare a Glauber coherent state? [closed]

Without using a laser source. Can you, for example, create a coherent state by filtering another light source (incandescent light bulb, LED, etc)?
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2answers
999 views

Reference request: Susskind-Glogower original paper

I'm trying to find Susskind and Glogower's original paper, L. Susskind and J. Glogower. Quantum mechanical phase and time operator. Physics 1 (1964) 49-61 where they propose their exponential ...
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39 views

How do pulse properties relate to the pulse's peak power?

Let's say we know the temporal shape of an optical pulse, which is $E(t) = E_0 \cdot f(t)$, where $E(t)$ is the electric field, $E_0$ its amplitude and $f(t)$ the shape function (e.g. $sech^2$, ...
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29 views

Vaccuum expectations for a string of creation and annihilation operators

I want to determine the vaccum expectation value of a string of creation and annihilation operators. They have a very specific form: $$\langle \prod_{i=1}^n \hat{a}(k_i) \, \, \hat{N}_1 \prod_{j=1}^n ...
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3answers
1k views

Is there a way to increase the speed of light itself?

When light enters materials it slows down due to its refractive index (due to absorbing and re-emission of photons). But, is there a way to increase the speed of light itself? Can there be some ...
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1answer
79 views

Wigner functions, symmetry

I'm trying to get more insight into quasiprobability distributions, as for example the Wigner function. There are some Wigner functions, which are symmetric. Symmetric: Fock state Thermal states ...
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3answers
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How is squeezed light produced?

Ordinary laser light has equal uncertainty in phase and amplitude. When an otherwise perfect laser beam is incident onto a photodetector, the uncertainty in photon number will produce shot noise with ...
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Can a simple harmonic oscillator describe Rabi oscillations?

I've been trying to simulate a resonant laser oscillation of a two level atom with Rabi frequency $\Omega$ and a rate of spontaneous emission $\Gamma$. So the wavefunction would be $\mid \Psi\rangle = ...
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370 views

Relation between representations of boson operators?

I have a simple (I think !) question about the representations of boson operators and how they are related. First of all let's define two conjugate observables $Q$ and $P$ (i.e. $\left[Q,P\right]=i$ ...
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When is quantum optics “correct”?

What is the regime under which we may consider quantum optics description of light a good approximation of a more correct theory such as QED? By quantum optics I mean describing the electromagnetic ...
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Why “vacuum” in vacuum Rabi splitting (VRS)?

What is the role of "vacuum" in vacuum Rabi splitting (VRS)? Also, does VRS arise because of quantized nature of light? If not, what is a semiclassical explanation for VRS?