Sharif Digital Repository

Bohmian mechanics (or de Broglie–Bohm theory) is a causal version of the quan-tum mechanics which its main idea was expressed for the first time by Louis de Broglie in 1927, and then rediscovered by David Bohm in 1952 with a different approach.In this theory, the state of a system of particles, is described by the position of the particles, and a wavefunction evolving according to the Schrödinger equation. John Bell in 1987, considering the double-slit experiment and emphasizing the importance of the Bohm’s wave-particle theory said: ”Is it not clear from the smallness of the scintillation on the screen that we have to do with a particle? And is it not clear,from the diffraction and... 

In the early time of the discovery of the quantum mechanics and some decades after that, various interpretations of quantum mechanics were proposed. However, many years after that, the “indetermenistic” perspective well-known for Copenhagen perspective which was proposed mostly by Bohr and his colleagues became the dominant attitude among physicists. But nearly two decades after the fixation point of the Copenhagen perspective, a new interpretation of quantum mechanics was proposed by Bohm which was nonlocal but deterministic and it could reproduce all the predictions of quantum mechanics.Bohm’s theory responded to the many theoretical and philosophical objections assumed to the Copenhagen... 

In spite of succesfull achievements of standard quantum mechanics in describing variety of physical phenomenons, this theory has some conceptual problems in some areas. One of the important problems is the behavior of macroscopic objects and their interaction with microscopic systems, which is called “measurement problem”. Actually because the standard quantum mechanic is linear, it anticipates the occurrence of superposition of macroscopic states which is in contrast with our understanding of macroscopic objects. The standard theory answers this problem by using the wave function reduction principle.
There has been various proposals about the mechanism of wave function reduction,... 

Quantum Theory leads to results that are consistent with the very high accuracy with experience and also includes a wide range of empirical phenomena. Hence, quantum mechanics is accepted as the best and most acclaimed physical theory. However, there is still no consensus between physicists on the interpretation of parts of this theory. One of the unresolved issues in quantum mechanics is the measurement problem. The basis of the measurement problem is a kind of transition from the quantum world to the classical world. The fundamental question that arises here is, where is the boundary between quantum mechanics and classical mechanics? and how can be described the transition from quantum... 

In recent years, weak measurement has been attracted attention in fundamental and applied physics. Instantaneous Measuring of noncommutative quantities, direct measurement of the quantum wave function, observation of Bohmian trajectories of photons, etc are among the issues that have been studied at the fundamental level by weak measurements. The idea has also been successful at the practical level, amplifying weak signals in the optical interferometers such as gravitational wave interferometer and increasing the sensitivity of the atomic magnetometer. In this thesis, after understanding the concept of time in the deterministic evolution (Schrodinger equation) and the measurement process, we...