Sharif Digital Repository

The electromagnetic (EM) force is the pivot on which this thesis revolves. We inspect different formulations of the distribution of the EM force (and momentum) inside matter, and show that the Einstein-Laub force density is incompatible with special relativity. We study the exerted EM force on small particles in depth, and explain when the conventional dipole approximation fails to yield accurate results. We propose an all-dielectric structure which is able to trap very small dielectric particles (of diameters as small as 10 nm). One of the achievements of this thesis is an explanation for an adverse phenomenon observed in many experiments on the optomechanical systems employing... 

Circuit model quantum computing, provides a powerful tool that allows humans to process information faster. Excessive noise and its impact on quantum systems which can lead to data loss are major obstacls in accessing quantum computers, since the systems proposed to make quantum computers are indeed open systems, noise can cause data loss. Therefore, the achievement of quantum computing, has been delayd. One of the most effective ways to neutralize this noise is to use a geometric phase to make evolutions. Holonomic quantum gates utilize the geometric phase to implement the noise resilience gate. In this thesis, we intend to use a composite optomechanical system, consisting of two optical... 

In this thesis, we study optomechanics of subwavelength nanoparticles based on the Green's function formulation. First, we investigate the optical force exerted upon Rayleigh particles in the free space using the dipole approximation method. Then, we present a new method based on the Taylor expansion of the polarization field to calculate the optical forces beyond the Rayleigh regime. Subsequently, we study the optical force exerted upon Rayleigh particles in non-free spaces, and model the backaction effect using the scattering Green's function. We show that the backaction effect can modify the polarizability of the particle and thereby can affect the gradient force, radiation pressure, and...