Javid Ziaei

The spread of using communication technologies has made it necessary to take certain measures to prevent illegal copying. Watermarking techniques are of great potential value in this regard. The present study introduces a watermarking scheme as a block cypher. We use entropy for sorting the blocks. The sorted blocks after finite ridgelet transforma...

We explore the issue of eigenstate localization in a two-dimensional photonic resonator lattice. In the system of our purpose, by harmonically modulating coupling constants between the resonators an effective magnetic field is imposed on the motion of a photon. From the study on the spectral fluctuantions and participation ration of eigenstates we...

DNA nanotechnology is a purist's approach to biomolecular engineering. The field aims to create molecular structures and devices through the exclusive use of DNA as an engineering material. On the other hand, creating of a molecular transistor as well as engineering its structure have become one of the greatest aims of scientists. We have focused o...

This presentation summarizes a part of my PhD thesis focusing on the four hot topics of physics from the quantum chaos point of view: 1. metal-insulator transition in a square nanotube, 2, 3. the second- and third- harmonic generations, as the commonly used nonlinear optics methods for doubling and tripling the frequency of light, respectively,...

Large optical nonlinearities are critical to photonic technologies, and generation of harmonics is a convenient way of producing new wavelengths of light. In particular, third-harmonic generation from infrared sources is often used as a source of ultraviolet light. In this paper, we study the stability of the dynamics of the process of intracavity...

Nonlinear optics (NLO) deserves special attention in new optical devices, making it possible to generate coherent light more efficiently. Among the various NLO phenomena the third-harmonic generation (THG) is at the core of the effective operating mechanism of broadband wavelength conversion, in all-optical devices. Here, we aim to understand how t...

Tailoring the propagation of light in an arbitrarily manner has motivated a great of interest on nanophotonics. As a new mechanism for this purpose, the generation of an effective magnetic field leading to a Lorentz force for photons is recently proposed in a photonic resonator lattice. Here, we consider a photonic resonator lattice with a harmonic...

Molecule–based transistors have attracted most attention due to their exclusive properties. Creating of a molecular transistor as well as engineering its structure have become one of the greatest aims of scientists. We have focused on the environmental dependent behavior of a DNA–templated transistor. Using the statistical distribution of the energ...

The promise of molecular electronics has focused enormous interest on molecular devices. Typically, such devices consist of an individual molecule trapped between two leads, in–between which a voltage bias is applied. Here, we have attempted to design a DNA based molecular transistor. Our aim is choosing the most appropriate parameters such as DNA...

Introduction: The development of the ultrafast laser pulses has paved the way towards the use of the strong and localized nonlinear-optical interactions and optically operation inside the living cells at nano scale. At the focal point, the power density of light is high, and each pulse causes a microscopic bubble which cuts the surrounded cellular...

The advent of molecular electronics has fueled interest in studying DNA as a nanowire. The well–known Peyrard– Bishop–Dauxois (PBD) model, which was proposed for the purpose of understanding the mechanism of DNA denaturation, has a limited number of degrees of freedom. In addition, considering the Peyrard–Bishop–Holstein (PBH) model as a means of s...

We have theoretically investigated the effect of a random distribution of the substitutional Nitrogen (N) atoms and external electric field on the electronic structure of zigzag graphene nanoribbons (ZGNRs). According to the Anderson Localization theory, the wave functions of a sufficiently strong disordered systems are localized. By using the tigh...

The highly controllable environments, produced by photonic crystals, provide new routes for control of the light. To generate an effective magnetic field, a photonic resonator crystal, with harmonically modulated coupling phase between nearest-neighbor resonators, are utilized to control of photons in this paper. The stability of quantum optical no...

Graphene nanoribbons (GNRs) have seized strong interest in nanoelectronics industry. Using the Tight-Binding (TB) calculations we have investigated the effect of a random distribution of the substitutional boron (B) atoms on the electronic properties of armchair GNR (AGNRs). We use the quantum chaos tools to observer the transition phenomena .Our r...

The emergence of second-harmonic generation (SHG) is a pivotal issue to the development of nano-optical devices and interfaces. Here, we perform a classical analysis of the SHG dynamics with the aim of determining critical values of the electric field. The signals of the SHG process are nonlinear, so it seems reasonable that chaos theory can be a s...

Second-harmonic generation as a frequency doubling process is ubiquitous in modern optical systems. The present study explores prospects of the stability region of second-harmonic generation in a medium coupled to a bosonic bath. We show that a stability–instability transition due to the combined action of driving field and nonlinearity coupling is...

We investigate the effects of disorder on the electron transport properties of graphene nanoribbons (GNs) with armchair edges described in tight-binding (TB) model. We try to compare the electronic properties of armchair graphene nanoribbons (AGNs) subjected to two types of disorder with different distributions. In this regard, the tight-binding mo...

The emergence of second-harmonic generation (SHG) is a pivotal issue to the development of nano-optical devices and interfaces. Here, we perform a quantum analysis of the spectral statistics of the SHG resonances with the aim of determining the instability of this process. We compute different independent statistical properties to being chaotic. We...

According to the Anderson localization theory, the wavefunctions of a sufficiently strong disordered system are localized. We show that shifting hopping energy between nearest neighbors would induce an anomalous localization-delocalization transition in a disordered square lattice nanotube modelled by tight-binding. For this purpose, the consecutiv...

Molecular electronics is complementary to Silicon-based electronics and may induce electronic functions which are difficult to obtain with conventional technology. We have considered a DNA based molecular transistor and study its transport properties. The appropriate DNA sequence as a central chain in molecular transistor and the functional interva...

Spurious coupling between pacemaker components may turn normal ECG signals into chaotic ones. Present study introduces a new chaos control approach known as dynamical control to retain normal signals. To this end, phase space diagram method is used for comparing between before and after of control. The obtained results confirm that the proposed met...

The electronic transport through a nano-scale device is an interesting topic for both experimental and theoretical physicists, addressing development of new nano-devices. Among the synthesized carbon nanostructures as the materia prima for development of nano-devices, graphene sheets has attracted a lot of attention among researchers. Exceptional p...

The change of external factors can alter heartbeat dynamics. So, a comprehensive study of such a system requires a mathematical model to simulate its behavior under various conditions and new techniques to explore additionally the heartbeat dynamics. The signals of the heart are nonlinear, so it seems reasonable that chaos theory can be a suitable...

Since cardiac system is capable of exhibiting chaotic behaviors, many works have been carried out to study its dynamics. In this paper, based on Grudzi ́ nski ̇ and Zebrowski’s model, the impacts of external periodic stimuli on cardiac impulses were studied using the scale index and Lyapunov exponent. Obtained results revealed that the scale index...

The study of cardiac dynamics by mathematical models has a long history that has been started by using nonlinear oscillators to generate such rhythms. Since cardiac rhythms may exhibit chaotic behaviors, the chaos theory as a powerful tool in studying nonlinear dynamical systems, can be used for analyzing cardiac system. In this paper, based on Gru...

The study of cardiac dynamics by mathematical models has a long history that has been started by using nonlinear oscillators to generate such rhythms. Since cardiac rhythms may exhibit chaotic behaviors, the chaos theory as a powerful tool in studying nonlinear dynamical systems, can be used for analyzing cardiac system. In this paper, based on Gru...