Mandel Q Parameter Research Articles

Berry phase and the Mandel parameter of the non-degenerate parametric amplifier

We study the non-degenerate parametric amplifier problem from an algebraic approach of the SU(1,1) group. We write the Hamiltonian of this problem in terms of the boson generators of the SU(1,1) group and the difference operator. We apply the tilting transformation to our results to exactly solve this Hamiltonian and obtain its energy spectrum and eigenfunctions. Then, by assuming that our Hamiltonian is an explicit function of time, we calculate its Berry phase. Finally we obtain the Mandel Q-parameter of the photon numbers n a and n b .

Equivalent non-rational extensions of the harmonic oscillator, their ladder operators and coherent states

In this work, we generate a family of quantum potentials that are non-rational extensions of the harmonic oscillator. Such a family can be obtained via two different but equivalent supersymmetric transformations. We construct ladder operators for these extensions as the product of the intertwining operators of both transformations. Then, we generate families of Barut–Girardello coherent states and analyze some of their properties as temporal stability, continuity on the label, and completeness relation. Moreover, we calculate mean-energy values, time-dependent probability densities, Wigner functions, and the Mandel Q-parameter to uncover a general non-classical behavior of these states.

A Jaynes-Cummings Model with a Landau-Zener Interaction

The Jaynes-Cummings Model has been a standard paradigm for light-matter interaction for a few decades. The Lie algebraic properties of the model permits us to solve for the time evolution of a coupled radiation-matter system. In this work we study the model with linear time dependence and show that it is analytically solvable. We use our results to calculate the Mandel Q-parameter which shows how nonclassical the resulting radiation state is.

Effect of intensity-dependent couplings and the atomic dissipation on the interaction of two three-level atoms and two modes of radiation field

The effect of intensity-dependent coupling and the atomic dissipation on the interaction of a pair of three-level atoms in the $$\Xi$$ configuration with a bi-mode cavity field are studied. The solution of the proposed model is obtained in the resonance case. Some statistical quantities are discussed to discover the characteristics of the model. With different nonlinearity functions, the population inversion and the photon number dynamics, which display the phenomenon of collapses and revivals are discussed. The non-classical effects by examining the Mandel Q-parameter are considered. The amount of correlation between the two atoms and the field is estimated by analyzing the results of the fidelity. The entanglement periods between the parts of the quantum system, the collapse and revival periods were affected by the choice of coupling intensity, where the collapse periods improved with increasing the effect of the Rabi frequency and decreased when the effect of the Rabi frequency decreased.

Theoretical studies on quantum imaging with time-integrated single-photon detection under realistic experimental conditions

We study a quantum-enhanced differential measurement scheme that uses quantum probes and single-photon detectors to measure a minute defect in the absorption parameter of an analyte under investigation. For the purpose, we consider two typical non-classical states of light as a probe, a twin-Fock state and a two-mode squeezed vacuum state. Their signal-to-noise ratios (SNRs) that quantifies the capability of detecting the defect are compared with a corresponding classical imaging scheme that employs a coherent state input. A quantitative comparison is made in terms of typical system imperfections such as photon loss and background noise that are common in practice. It is shown that a quantum enhancement in SNR can be described generally by the Mandel Q-parameter and the noise-reduction-factor, which characterize an input state that is incident to the analyte. We thereby identify the conditions under which the quantum enhancement remains and can be further increased. We expect our study to provide a guideline for improving the SNR in quantum imaging experiments employing a differential measurement scheme with time-integrated single-photon detectors.

Four-level double V-type atomic system solved by virtue of supersymmetric unitary transformation

We consider a four-level double V-type atom with two closely-separated top levels and two closely-separated lower levels interacting with a single mode field via multi-photon processes and in the presence of Kerr medium. We show that this atomic system possesses supersymmetric structure and construct its supersymmetric generators. We diagonalize the Hamiltonian of this system using supersymmetric unitary transformation and obtain the corresponding eigenstates and eigenvalues. The atom–field wave functions are obtained when the atom and the field mode are initially in two different cases. The evolution of both the quasi-probability distribution Q-function and the Mandel Q-parameter of the field are studied when the input field is in a coherent state. The influence of the Kerr medium and the detuning parameters on the behavior of these quantum effects is analyzed. The results show that they play a prominent role on the Poissonian statistics of the field. Also, the Kerr medium changes the behavior of the quasi-probability distribution Q-function. We end with discussion and conclusions.

Quantum optomechanical system in a Mach-Zehnder interferometer

We consider an oscillating micromirror replacing one of the two fixed mirrors of a Mach-Zehnder interferometer. In this ideal optical set-up the quantum oscillator is subjected to the radiation pressure interaction of travelling light waves, no cavity is involved. This configuration shows that squeezed light can be generated by pure scattering on a quantum system, without involving a cavity. The squeezing can be detected at the output ports of the interferometer either by direct detection or by measuring the spectrum of the difference current. We use the Hudson-Parthasarathy equation to model the global evolution. It can describe the scattering of photons and the resulting radiation pressure interaction on the quantum oscillator. It allows to consider also the interaction with a thermal bath. In this way we have a unitary dynamics giving the evolution of oscillator and fields. The Bose fields of quantum stochastic calculus and the related generalized Weyl operators allow to describe the whole optical circuit. By working in the Heisenberg picture, the quantum Langevin equations for position and momentum and the output fields arise, which are used to describe the monitoring in continuous time of the light at the output ports. In the case of strong laser and weak radiation pressure interaction highly non-classical light is produced, and this can be revealed either by direct detection (a negative Mandel Q-parameter is found), either by the intensity spectrum of the difference current of two photodetector; in the second case a nearly complete cancellation of the shot noise can be reached. In this last case it appears that the Mach-Zehnder configuration together with the detection of the difference current corresponds to an homodyne detection scheme, so that we can say that the apparatus is measuring the spectrum of squeezing.

Non-classicality created by quantum channels with indefinite causal order

Non-classicality of output states of quantum channels with indefinite causal order is studied, where each channel maps any state to a fixed one. The causal indefiniteness means a coherent superposition of the order of which channel first interacts with a quantum system. Non-classicality of a single-mode photon system is investigated in terms of the non-classical depth and the Mandel Q-parameter. It is shown that the thermalizing channels with indefinite causal order can create non-classicality even when an input state is classical.

London-modified coherent states: statistical properties and interaction with a two-level atom

In this paper, we discuss the statistical properties of London-modified coherent states that were introduced in order to build up a resolution of the identity for London coherent states. The resolution to the identity is realized by the application of an operator to the London cohrent states. Next we find the Mandel-Q parameter that shows that there exist sub-Poissonian behaviour for a large interval of amplitudes, look at their behaviour in phase space through the Husimi-Q function and study their interaction with a two-level atom. We show that their oscillating photon distributions are responsible for the ringing revival behaviour shown by the atomic inversion.

Dynamics of entanglement and non-classicality features of a single-mode nonlinear Jaynes–Cummings model

Abstract In this paper, we discuss a model of a nonlinear interaction between a λ-type four-level atom interacting with a cavity field. The analytical solution of the system under particular conditions has been obtained. Numerical treatments have been discussed and new features of the entanglement degree are obtained using entropy and Mandel Q-parameter. Moreover, we evaluate a few of their non-classical properties such as momentum increment, momentum diffusion, mean photon number and normal squeezing. The Kerr medium impact has been discussed through different phenomena. It is shown that Kerr-like medium parameter can be used as a controller parameter of the system dynamics.

Photon-Added SU(1, 1) Coherent States and their Non-Classical Properties

The photon-added coherent states of Barut-Girardello and Perelomov types are constructed using Holstein-Primakoff realization of the su(1, 1) Lie algebra. Basic properties of the constructed states have been discussed. In addition, their non-classical features have been analyzed by computing photon detection probability distribution, Mandel Q-parameter and quadrature squeezing. It is shown that SU(1, 1) photon-added coherent states may exhibit sub-Poissonian statistics and quadrature squeezing for a chosen set of parameters. Moreover, it has been observed that their non-classical behavior increases as the number of added-photons increases.

Observation of Singlet Oxygen with Single-Molecule Photosensitization by Time-Dependent Photon Statistics

The singlet oxygen has been widely applied to the treatment of physiological diseases, and the photosensitized generation of singlet oxygen is the main means of its physiological applications. On the basis of the fluctuation of fluorescence field from single photosensitizer, we characterize the generation of singlet oxygen at single molecule level with the time-dependent photon statistical method. By measuring the time-tagged-time-resolved single-molecule fluorescence photons, we analyze the time-dependent Mandel-Q parameter, which has been performed at different oxygen environment. It is shown that the single molecule not only offers an efficient way of generating singlet oxygen in ambient condition but also provides insights for the fluctuation of singlet oxygen in the nanoscale environment. The method of time-dependent photon statistics provides a convenient methodology for observing photosensitizers generating singlet oxygen in real time at single photosensitizer level.

Damping in the Interaction of a Field and Two Three-Level Atoms Through Quantized Caldirola–Kanai Hamiltonian

We investigate the damped interaction between two Λ-type three-level atoms and a quantized single-mode cavity field, for which the Hamiltonian of the field is rewritten in Caldirola–Kanai form. We obtain the wave functions for the case where the two atoms are initially prepared in arbitrary pure states and the field is initially prepared in the coherent state. We investigate numerically the influence of the damping parameter on the temporal behavior of the Mandel Q-parameter, linear entropy, and normal squeezing. We find the damping parameter and initial atomic states to play central roles in the nonclassical features and the degree of entanglement.

The Interaction of a N-Type Four Level Atom with the Electromagnetic Field for a Kerr Medium Induced Intensity-Dependent Coupling

The interaction of a N-type four-level atom with a single field in the presence of an intensity-dependent coupling in a nonlinear Kerr medium is investigated. The exact analytic solution is obtained in the case that the atom and electromagnetic field are initially in a higher excited state and a coherent state, respectively. It is then demonstrated that effects such as nonclassical light generation, degree of entanglement stabilization, Kerr medium nonclassical control, and squeezed light are can be more efficiently implemented within this four-level framework than in many competing procedures. Additionally, inversion, linear entropy, Mandel Q-parameter and normal squeezing dynamics are examined.

A moving three-level atom interacting with a two-mode field: some atom–field aspects

In this paper, the interaction of a moving three-level atom and a two-mode quantized electromagnetic cavity field is extended to involve the effects of the atomic motion. Detuning parameters, Kerr nonlinearity, Stark shift contributions and arbitrary forms of intensity-dependent atom–field coupling have been taken into account. The constants of motion and the wave function, when the atom is initially prepared in superposition states and the field is initially prepared in squeezed coherent states, have been obtained. We calculate some statistical aspects such as atomic inversion, purity, Mandel Q-parameter, cross-correlation, momentum increment, momentum diffusion and Husimi Q-function.

Dynamics of three-level Λ-type atom interacting with one mode cavity field with both classical gravity and quantum radiation: Lie algebra approach

In this paper, a model is introduced to investigate the interaction between a three-level atom and one-mode of the radiation field. The atomic motion and the classical homogenous gravitational field are taken into consideration. For this purpose, we first introduce a set of new atomic operators obeying an su(3) algebraic structure to derive an effective Hamiltonian for the system under consideration. By solving the Schrodinger equation in the interaction picture, the exact solution is given when the atom and the field are initially prepared in excited state and coherent state, respectively. The influences of the gravity parameter on the collapses-revivals phenomena, the atomic momentum diffusion, the Mandel Q-parameter, the normal squeezing phenomena and the coherent properties for the considered system are examined. It is found that the gravity parameter has important effects on the properties of these phenomena.

Supersymmetric Displaced Number States

We introduce, generate and study a family of supersymmetric displaced number states (SDNS) that can be considered generalized coherent states of the supersymmetric harmonic oscillator. The family is created from the seminal supersymmetric boson-fermion entangling annihilation operator introduced by Aragone and Zypman and later expanded by Kornbluth and Zypman. Using the momentum representation, the states are obtained analytically in compact form as displaced supersymmetric number states. We study their position-momentum uncertainties, and their bunchiness by classifying them according to their Mandel Q-parameter in phase space. We were also able to find closed form analytical representations in the space and number basis.

Nonclassical and non-Gaussian properties of states generated by the superposed photon added-and-subtracted operation on squeezed vacuum

A new kind of non-Gaussian quantum state is constructed by operating the superposed operator (SO) (cosθaa†+sinθa†a) on a squeezed vacuum state (SVS) S(r)|0〉. It is found that the SOSVS is just a superposition state between S(r)|0〉 and S(r)|2〉 with only even numbers of photons. The nonclassicality is investigated by exploring the negativity of Wigner function (WF) and the sub-Poissonian distribution of Mandel's Q-parameter. The non-Guassianity is exhibited via the fidelity between the SOSVS and the SVS and the marginal distribution of its Wigner function. It is found that such SO on the SVS can enhance the nonclassicality and change the non-Gaussianity of the SOSVS. This provides the possibility of generating quantum states with specific nonclassical and non-Gaussian properties.

Nonclassical properties and decoherence of fields in photon-added squeezing-enhanced thermal states

We put forward the photon-added squeezing-enhanced thermal states (PASETS) theoretically by adding photon to the squeezed enhancing thermal states (SETS) repeatedly. Based on the normally ordered density operator of PASETS, we investigate the nonclassical behavior of the PASETS by evaluating, both analytically and numerically, Mandel's Q-parameter, photon-number distribution (PND), and Wigner function (WF). It is found that smaller squeezing parameter r and thermal photon number nc can lead to more chance of the appearance of sub-Poissonian statistics. And it is shown that the PND of PASETS exhibit more remarkable oscillations than that of SETS in stronger squeezing case. The WF exhibit partial negativity in phase space and the squeezing parameter r can result in both squeezing and rotating effect. By investigating the fidelity between PASETS and SETS shows that the fidelity tender to steady values in the high value of squeezing parameter or thermal photon number. In addition, the decoherence effect on the PASETS is examined by the time-evolution of the analytical WF in thermal channel. The results show that the PASETS shall lose nonclassicality and non-Gaussianity and reduce to classical states with Gaussian distribution after sufficient time interaction with the thermal noise. And larger photon-added number or thermal photon number shall render shorter decoherence time.

Comparison between photon annihilation-then-creation and photon creation-then-annihilation thermal states: Non-classical and non-Gaussian properties

We investigate the nonclassical properties of arbitrary number photon annihilation-then-creation operation (AC) and creation-then-annihilation operation (CA) to the thermal state (TS), whose normalization factors are related to the polylogarithm function. Then we compare their quantum characters, such as photon number distribution, average photon number, Mandel Q-parameter, purity and the Wigner function. Because of the noncommutativity between the annihilation operator and the creation operator, the ACTS and the CATS have different nonclassical properties. It is found that nonclassical properties are exhibited more strongly after AC than after CA. In addition we also examine their non-Gaussianity. The result shows that the ACTS can present a slightly bigger non-Gaussianity than the CATS.