  In this thesis, we have proposed some novel thought experiments involving
foundations of quantum mechanics and quantum information theory, using quantum
entanglement property. Concerning foundations of quantum mechanics, we have
suggested some typical systems including two correlated particles which can
distinguish between the two famous theories of quantum mechanics, i.e. the
standard and Bohmian quantum mechanics, at the individual level of pair of
particles. Meantime, the two theories present the same predictions at the
ensemble level of particles. Regarding quantum information theory, two
theoretical quantum communication schemes including quantum dense coding and
quantum teleportation schemes have been proposed by using entangled spatial
states of two EPR particles shared between two parties. It is shown that the
rate of classical information gain in our dense coding scheme is greater than
some previously proposed multi-qubit protocols by a logarithmic factor
dependent on the dimension of Hilbert space. The proposed teleportation scheme
can provide a complete wave function teleportation of an object having other
degrees of freedom in our three-dimensional space, for the first time. All
required unitary operators which are necessary in our state preparation and
Bell state measurement processes are designed using symmetric normalized
Hadamard matrix, some basic gates and one typical conditional gate, which are
introduced here for the first time.
