Nonclassicality of photon-added-then-subtracted and photon-subtracted-then-added states

We formulate the density matrices of a quantum state obtained by first adding multi-photons to and then subtracting multi-photons from any arbitrary state as well as performing the same process in the reverse order. Considering the field to be initially in a thermal (or in an even coherent) state, we evaluate the photon number distribution, Wigner function and Mandel's $Q$ parameter of the resulting field. We show graphically that in which order multi-photons are added and subtracted has a noticeable effect on the temporal behavior of these statistical properties.Comment: 9 pages, 7 figure

Lower-vs-Higher Order Non-classicality of Photon-added Bell-type Entangled Coherent States

We compare the lower and higher order non-classicality of a class of the photon-added Bell-type entangled coherent states (PBECS) got from Bell-type entangled coherent states using creation operators. We obtained lower and higher order criteria namely Mandel's $Q_m^l$, antibunching $d_h^{l-1}$, Subpoissioning photon statistics $D_h(l-1)$ and Squeezing $S(l)$ for the states obtained. Further we observe that first three criteria does not gives non-classicality for any state and higher order criteria gives very high positive values for all values of parameters. Also the fourth or last criterion $S(l)$ gives non-classicality for lower order as well as higher order.Comment: published in conference proceeding

General expansion of natural power of linear combination of Bosonic operators in normal order

In quantum mechanics, bosonic operators are mathematical objects that are used to represent the creation ($a^\dagger$) and annihilation ($a$) of bosonic particles. The natural power of a linear combination of bosonic operators represents an operator $(a^\dagger x+ay)^n$ with $n$ as the exponent and $x,\,y$ are the variables free from bosonic operators. The normal ordering of these operators is a mathematical technique that arranges the operators so that all the creation operators are to the left of the annihilation operators, reducing the number of terms in the expression. In this paper, we present a general expansion of the natural power of a linear combination of bosonic operators in normal order. We show that the expansion can be expressed in terms of binomial coefficients and the product of the normal-ordered operators using the direct method and than prove it using the fundamental principle of mathematical induction. We also derive a formula for the coefficients of the expansion in terms of the number of bosons and the commutation relation between the creation and annihilation operators. Our results have important applications in the study of many-body systems in quantum mechanics, such as in the calculation of correlation functions and the evaluation of the partition function. The general expansion presented in this paper provides a powerful tool for analyzing and understanding the behavior of bosonic systems, and can be applied to a wide range of physical problems.Comment: submitted in conference proceeding

Detecting nonclassicality and non-Gaussianity of a coherent superposed quantum state

In this paper, we investigate the nonclassicality and non-Gaussianity of a coherent superposed quantum state (CSQS) which is obtained by applying a coherent superposition of field annihilation ($a$) and creation ($a^\dagger$) operators, $N(ta+ra^\dagger)$ to a classical coherent state $|\alpha\rangle$, where $t$ and $r$ are scalars with $t^2+r^2=1$. Such an operation, when applied on states having classical characters, introduces strong nonclassicality. We use different criteria to check the nonclassicality and non-Gaussianity of the considered quantum state. We first compute the Wigner function of CSQS. To study the nonclassicality of the considered state we further use (i) linear entropy (LE) (ii) Wigner logarithmic negativity (WLN) and (iii) skew information based measure. Relative entropy based measure is considered to analyze the variation in non-Gaussianity of CSQS. Finally, the dynamics of the Wigner function evolving under the photon loss channel is addressed to probe the effect of noise on nonclassicality as well as non-Gaussianity of CSQS.Comment: 9 pages, 7 figures. arXiv admin note: text overlap with arXiv:2109.12145 by other author

Realistic continuous-variable quantum teleportation using a displaced Fock state channel

We investigate ideal and non-ideal continuous-variable quantum teleportation protocols realized by using an entangled displaced Fock state resource. The characteristic function formulation is applied to measure the relative performance of displaced Fock state for teleporting squeezed and coherent states. It is found that for such single-mode input fields, the average fidelity remains at the classical threshold, suggesting that the displaced Fock states are not advantageous for teleportation. We also discuss the major decoherence effects, caused by the inaccuracy in Bell measurements and photon losses for the propagation of optical fields via fibre channels. The changes in the teleportation fidelity are described by adjusting the gain factor ($g$), reflectivity ($R$), mode damping ($\tau$), and the number of thermal photons ($n_\mathrm{th}$). The possibility of successful teleportation can be optimized by fixing these realistic parameters.Comment: 16 pages, 9 figure

Detecting Nonclassicality and quantum non-Gaussianity of photon subtracted displaced Fock state

In this paper, a quantitative investigation of the non-classical and quantum non-Gaussian characters of the photon-subtracted displaced Fock state $|{\psi}\rangle=a^kD(\alpha)|{n}\rangle$, where $k$ is number of photons subtracted, $n$ is Fock parameter, is performed by using a collection of measures like Wigner logarithmic negativity, linear entropy potential, skew information based measure, and relative entropy of quantum non-Gaussianity. It is noticed that the number of photons subtracted ($k$) changes the nonclassicality and quantum non-Gaussianity in a significant amount in the regime of small values of the displacement parameter whereas Fock parameter ($n$) presents a notable change in the large regime of the displacement parameter. In this respect, the role of the Fock parameter is found to be stronger as compared to the photon subtraction number. Finally, the Wigner function dynamics considering the effects of photon loss channel is used to show that the Wigner negativity can only be exposed by highly efficient detectors.Comment: 15 pages and 9 figures. arXiv admin note: substantial text overlap with arXiv:2109.12145 by other author

Lower- versus higher-order nonclassicalities for a coherent superposed quantum state

A coherent state is defined conventionally in different ways such as a displaced vacuum state, an eigenket of annihilation operator or as an infinite dimensional Poissonian superposition of Fock states. In this work, we describe a superposition $(ta+ra^\dagger)$ of field annihilation and creation operators acting on a continuous variable coherent state $|{\alpha}\rangle$ and specify it by $|\psi\rangle$. We analyze the lower- as well as the higher-order nonclassical properties of $|\psi\rangle$. The comparison is performed by using a set of nonclassicality witnesses (e.g., higher-order photon-statistics, higher-order antibunching, higher-order sub-Poissonian statistics, higher-order squeezing, Agarwal-Tara parameter, Klyshko's condition and a relatively new concept, matrix of phase-space distribution). It is found that higher-order criteria are much more efficient to detect the presence of nonclassicality as compared to lower-order conditions.Comment: 10 pages, 10 figure

Consumeras Acceptance towards Genetically Modified Crops and Growth of the Economy: A Theoretical Approach

This paper develops a three-sector theoretical growth model to capture the role of consumers acceptance towards the second generation of genetically modified GM crops in the long run growth process of the economy An Acceptance towards GM crop parameter is defined as a ratio of consumption of GM to traditional variety of food whose growth rate is determined by growth rate of human capital Dynamic stability of the system is ensured provided the value of acceptance parameter is within a certain range A range of the acceptance parameter is also obtained which ensures not only the dynamic stability of the system but also ensures higher rate of growth of an economy that produces both GM and non-GM crops compared to an economy that does not produce GM crops The empirical validation of the model through panel data analysis suggests that research and development activity in agriculture is key to the growth process of the economy as it helps to form acceptance towards new technology among consumer