Antibunching Effect Research Articles

The effect of two-photon quantum interference on amplitude-squared squeezing of a quantum field

In this paper, we consider a superposition of a weak coherent field and a two-photon source and examine the amplitude-squared squeezing (ASS) properties of the combined field. We demonstrate that the efficient and lasting ASS effect of the field could be observed due to constructive two-photon quantum interference. The relationship between ASS and photon antibunching effects is discussed. It is found that photon antibunching may accompany weak ASS, but in most cases ASS effects appear accompanying photon bunching.

Quantum statistical properties of off-resonant mode coupling for quadrupole excitations in a BEC

It is predicted that for the case of off-resonant coupling between two collective excitations of a Bose–Einstein condensed gas (BEC), the two modes may exhibit the antibunching effect. Correlation between them is nonclassical, which means that there exists a violation of the Cauchy–Schwartz inequality.

Nonclassical properties of orthonormalized eigenstates of the operator (a(q) f (N-q))(k)

In this paper, the completeness of the k orthonormalized eigenstates of the operator (a(q) f(N-q))(k)(k greater than or equal to 3) is proved. We introduce a new kind of higher order squeezing and an antibunching. The properties of the Mth-order squeezing and the antibunching effect of the k states are investigated. The result shows that these states may form a complete Hilbert space, and the Mth order [M = (m + 1/2)k; m = 0, 1, 2....] squeezing effects exist in all of the k states when k is even. There is the antibunching effect in all of the states.

Observation of nonclassical photon statistics due to quantum interference.

Phase-dependent photon statistics is observed in the mixed field of a narrow band two-photon source and a coherent field. At a certain phase, the nonclassical effect of photon antibunching occurs while at another the photon bunching effect appears. Furthermore, we observed a novel nonclassical phenomenon that exhibits more complex structure. The different features in photon statistics are attributed to a two-photon interference effect.

Quantum Theory of Self‐Phase Modulation of Ultrashort Light Pulses in a Medium with Inertial Electronic Nonlinearity

We develop a systematic quantum theory of formation of ultrashort light pulses in a squeezed state at self‐phase modulation. The response time of the electronic Kerr nonlinearity of the medium is accounted for and the dispersion of linear properties of the medium is described in first approximation. The theory uses the approach based on the momentum operator for the electric field. The response function of the nonlinearity is contained in the interaction operator. The results obtained are valid when the pulse duration is far greater than the nonlinear response time and the carrier pulse frequency is off‐resonance. It is established that the instantaneous spectral distribution depends quasistatically on the pulse form. In the general case, the spectral distribution of the quadrature‐squeezed component is defined by both the response time of the nonlinearity and the magnitude of the nonlinear phase addition. It is also shown that the frequency at which suppression of quantum fluctuations is greatest can be controlled by adjusting the phase of the initial coherent light pulse. It is found that, by registering the quadrature‐squeezed pulse using a balanced homodyne detector, the squeezing effect can be efficiently measured if the time‐dependent phase of the heterodyne pulse obeys a specific dependence defined by the pulse form. The spectral photon‐number distribution of the quadrature‐squeezed pulse is studied, and the photon antibunching effect is found for the photon number in a limited spectral band.

Inequalities for electron-field correlation functions

We show that there exists a class of inequalities between correlation functions of different orders of a chaotic electron field. These inequalities lead to the antibunching effect and are a consequence of the fact that electrons are fermions: indistinguishable particles with antisymmetric states. The derivation of the inequalities is based on the known form of the correlation functions for the chaotic state and on the properties of matrices and determinants.

Displaced Excited Squeezed Vacuum States and Their Propertities

We introduce the states D(z)a\+\{+\+m\}S(r)|0〉 and examine their properties . Such states are checked to be complete vectors via the IWOP (Integration W ithin an Ordered Product of operators) technique. We find larger－scale macrosco pic oscillations of photon distribution after the squeezed vacuum states being e xcited and displaced. On contrary to the bunching photons of the squeezed vacuum states as the displacing parameter |z| and the excitation number m are both small photons coherence can exhibit antibunching effect. The quasi－proba bility distribution functions (Husimi Q( 醆+*) function and Wigner W(q p) function) are derived and their dependences on the three parameters (z m r) are discussed. The Wigner function obviously displays their nonclassical fe ature.

Unified Approach for the Kerr Effect, Stark Effect and Doppler Effect in the Atom-Field Interaction

We solve the atom-field interaction model including the Kerr effect, Stark effect and Doppler effect exactly within a unified approach. The detuning in the effective Hamiltonian depends on two conserved operators of the system. Finally, the influence of atomic mass-center-motion on the antibunching effect of photons is discussed.

Electronic-field correlation functions

In this paper the correlation function of an arbitrary order is derived for an electron field in which the components corresponding to different particle numbers and momenta are mutually uncorrelated. The result is expressed in terms of the complex degree of coherence. The correlation functions clearly demonstrate the antibunching effect. All the computational steps are shown in detail.

Even and odd qs-coherent states and their photon-statistical properties

We construct explicitly even and odd qs-coherent states ( qs-CSs), which are proved to form a representation of the quantum Heisenberg-Weyl algebra, and use the numerical method to study the influences of q and s deformations on photon-statistical properties of even and odd qs-CSs. It is shown that nonclassical properties of the even and odd qs-CSs are very different from those of the usual even and odd coherent states (CSs). It is found that the squeezing and antibunching effects appear for both even and odd qs-CSs in some range of the parameters q, s and r. The smaller the q ( q < 1) and s, the larger the difference between the even and odd qs-CSs and the usual even and odd CSs.

Mathematical structure of quasi-SU(2) coherent state and its antibunching effect

The mathematical structure of the quasi-SU(2) coherent state is studied, and its antibunching property is investigated. It is found that the quasi-SU(2) coherent state may form a complete Hilbert space, and it can show an antibunching effect.

QUANTUM DYNAMICS OF A CASCADE THREE-LEVEL ATOM INTERACTING WITH COHERENT STATE IN THE COUNTER ROTATING WAVE APPROXIMATION

The dynamics of a cascade three-level atom interacting with the single mode coherent state under the Counter-Rotating-Wave approximation (C-RWA) is investigated.The properties of the mean-photon number (N(t)) and the degree of second-order coherence (g2(t)) are analyzed in this model.The little indentation which represents the quantum noise of the system appears in the evolution curves of the mean-photon number and the degree of second-order coherence under the C-RWA.The quantum noise which is caused by the virtual photon field gradually becomes weak when ω increases.The quantum noise increases when increases.The anti-bunching effect of the system under the C-RWA is stronger than the one under the RWA.Besides,the relation of N(t) and g2(t) with the atom-field coupling constant λ is revealed in our results.

Quantum Statistical Properties of Even and Odd qs-Coherent States**The project partially supported by Natural Science Foundation of Shandong Province of China

In this paper, we use the numerical method to study the influences of and deformations on the quantum statistical properties of even and odd qs-coherent states. It is shown that nonclassical properties of the even and odd qs-coherent states are very different from those of the usual even and odd coherent states. It is found that squeezing and antibunching effect appear for both even and odd qs-coherent states in some range of the parameters , and . The smaller the and are, the larger the difference between the even and odd qs-coherent states and the usual even and odd coherent states is.

Even and odd q-coherent states in a finite-dimensional basis and their squeezing properties

The even and odd coherent states of a deformed harmonic oscillator in a finites-dimensional Hilbert space are studied. It is shown that both fors even ands odd, the even q-coherent states exhibit quadrature and amplitude-squared squeezing, while the odd q-coherent states show an antibunching effect and amplitude-squared squeezing.

Eigenstates of the Operator and Their Antibunching Effect11The project partially supported by Natural Science Foundation of Shandong Province of China

In this paper, the mathematical structure and properties of orthonormalized eigenstates of the higher powers of the annihilation operator of two-parameter deformed harmonic oscillator are studied. Based on the work, the antibunching properties of them are investigated. It is found that they may form a complete Hilbert space, and all of them show antibunching effect.

ANTIBUNCHING EFFECT OF TWO PHOTON FLUORESCENT LIGHT FOR A TWO LEVEL ATOM IN A SQUEEZED VACUUM

By using the two photon Bloch equation and quantum regression theorem, the second order correlation function of two photon fluorescence of a two level atom in a broad band squeezed vacuum is obtained. From this, the bunching and the antibunching effects of two photon fluorescence are investigated. We find that the second order correlation function is dependent on the squeezing parameter (|M|) of the squeezed vacuum. There is a critical value (Γ/4g) for |M|,above which the second order correlation function oscillates around 1. This indicates that the two photon fluorescence can exhibit both antibunching and bunching effects. Below the critical value, the second order correlation function does not oscillate and the two photon fluorescence exhibits the antibunching effect only.

HIGHER POWER SQUEEZING AND ANTIBUNCHING EFFECTS FOR GENERALIZED ODD AND EVEN COHERENT STATES OF A NON HARMONIC OSCILLATOR

Theoretical calculations show that the generalized odd and even coherent states(OECS) of a non harmonic oscillator represent higher power (odd number power) squeezing effect and antibunching effect respectively, and these photon statistical characteristics are very different from those of the ordinary OECS.

Dynamical evolution of squeezing and antibunching effects in a quantum chaotic system: The three-level Lipkin model.

Dynamical evolution of squeezing and antibunching effects in a quantum chaotic system: The three-level Lipkin model.

Quantum-noise reduction in semiconductor lasers

A second-order correlation function approach is adopted to focus on the mechanism for generating amplitude-squeezed light in a semiconductor diode laser pumped with suppressed amplitude fluctuations. Second-order correlation functions between the electromagnetic field intensities and between the electromagnetic field intensities and the charge carrier numbers are calculated. Sub-Poissonian statistics and antibunching effects inside the laser cavity are analyzed; the analysis focuses on various quantities responsible for generating this state of the field. The influence of these quantities on the noise spectra of the detected field and conditions for quantum-noise reduction are considered.

Higher moment properties of k-boson q-coherent states

We introduce the squeezing, higher moment squeezing and antibunching effect for the q-electromagnetic field, and study these quantum statistical properties of eigenstates of the operator a q k ( k≥3) given by Kuang and Wang [Phys. Lett. A 173 (1993) 1]. The results show that the states have Nth-power squeezing ( N = (m + 1 2 )k , m = 0, 1, 2, …) when k is even, and all of them show the antibunching effect.