arXiv subjects

M. Amooshahi

Publications and source records attributed to M. Amooshahi.

13 recordsLinked to original sources

arXiv2010

Canonical quantization of the electromagnetic field in the presence of non-dispersive bi-anisotropic inhomogeneous magnetodielectric media

By introducing a suitable Lagrangian, a canonical quantization of the electromagnetic field in the presence of a non-dispersive bi-anisotropic inhomogeneous magnetodielectric medium is investigated. A tensor projection operator is defined and the commutation relation between the vector potential and its canonically conjugate variable is written in terms of the projection operator. The quantization method is generalized in the presence of the atomic systems. The spontaneous emission of a two-level atom located in a non-dispersive anisotropic megnetodielectric medium is studied.

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arXiv2009

Canonical quantization of a dissipative system interacting with an anisotropic non-linear absorbing environment

A canonical quantization scheme is represented for a quantum system interacting with a nonlinear absorbing environment. The environment is taken anisotropic and the main system is coupled to its environment through some coupling tensors of various ranks. The nonlinear response equation of the environment against the motion of the main system is obtained. The nonlinear Langevin-schrödinger equation is concluded as the macroscopic equation of motion of the dissipative system. The effect of nonlinearity of the environment is investigated on the spontaneous emission of an initially excited two level-atom imbedded in such an environmrnt.

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arXiv2009

A Canonical Relativistic Approach to Quantize Electromagnetic Field in the Presence of Moving Magneto-Dielectric Media

A canonical relativistic formulation is introduced to quantize electromagnetic field in the presence of a polarizable and magnetizable moving medium. The medium is modeled by a continuum of four vectors in a phenomenological way. The covariant wave equation for the vector potential and the covariant constitutive equation of the medium are obtained as the Euler- Lagrange equations using the Lagrangian of the total system. A tensor of the third rank which couples the electromagnetic field with the medium is introduced and the susceptibility tensor of the medium is obtained in terms of the coupling tensor. Also the noise polarization tensor is calculated in terms of the coupling tensor and the creation and annihilation operators of the four vectors modeling the medium.

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arXiv2008

Electromagnetic field quantization in an anisotropic magnetodielectric medium with spatial-temporal dispersion

By modeling a linear, anisotropic and inhomogeneous magnetodielectric medium with two independent set of harmonic oscillators, electromagnetic field is quantized in such a medium. The electric and magnetic polarizations of the medium are expressed as linear combinations of the ladder operators describing the magnetodielectric medium. The Maxwell and the constitutive equations of the medium are obtained as the Heisenberg equations of the total system. The electric and magnetic susceptibilities of the medium are obtained in terms of the tensors coupling the medium with the electromagnetic field. The explicit forms of the electromagnetic field operators are obtained in terms of the ladder operators of the medium.

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arXiv2007

Electromagnetic field quantization in a magnetodielectric medium with external charges

The electromagnetic field inside a cubic cavity filled up with a linear magnetodielectric medium and in the presence of external charges is quantized by modelling the magnetodielectric medium with two independent quantum fields. Electric and magnetic polarization densities of the medium are defined in terms of the ladder operators of the medium and eigenmodes of the cavity. Maxwell and constitutive equations of the medium together with the equation of motion of the charged particles have been obtained from the Heisenberg equations using a minimal coupling scheme. Spontaneous emission of a two level atom embedded in a magnetodielectric medium is calculated in terms of electric and magnetic susceptibilities of the medium and the Green function of the cubic cavity as an application of the model.

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arXiv2007

Electromagnetic field quantization in an anisotropic and inhomogeneous magnetodielectric

The electromagnetic field in an anisotropic and inhomogeneous magnetodielectric is quantized by modelling the medium with two independent quantum fields. Some coupling tensors coupling the electromagnetic field with the medium are introduced. Electric and magnetic polarizations are obtained in terms of the ladder operators of the medium and the coupling tensors explicitly. Using a minimal coupling scheme for electric and magnetic interactions, the Maxwell equations and the constitutive equations of the medium are obtained. The electric and magnetic susceptibility tensors of the medium are calculated in terms of the coupling tensors. Finally the efficiency of the approach is elucidated by some examples.

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arXiv2006

Dissipation in Quantum Mechanics, Scalar and Vector Field Theory

A new minimal coupling method is introduced. A general dissipative quantum system is investigated consistently and systematically. Some coupling functions describing the interaction between the system and the environment are introduced. Based on coupling functions, some susceptibility functions are attributed to the environment explecitly. Transition probabilities relating the way energy flows from the system to the environment are calculated and the energy conservation is explecitly examined. This new formalism is generalized to the dissipative scalar and vector field theories along the ideas developed for the quantum dissipative systems

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arXiv2005

Electromagnetic field quantization in a linear dielectric medium

By modeling a dielectric medium with two independent reservoirs, i.e., electric and magnetic reservoirs, the electromagnetic field is quantized in a linear dielectric medium consistently. A Hamiltonian is proposed from which using the Heisenberg equations, not only the Maxwell equations but also the structural equations can be obtained. Using the Laplace transformation, the wave equation for the electromagnetic vector potential is solved in the case of a homogeneous dielectric medium. Some examples are considered showing the applicability of the model to both absorptive and nonabsorptive dielectrics.

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arXiv2005

Spin Precession and Quantum Vacuum

The effect of quantum vacuum on spin precession is investigated. The radiation reaction is obtained and the time of spin flip (up state to down state) or spontaneous decay, is calculated.

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arXiv2005

Quantum electromdynamics in a linear absorbing dielectric medium

The eletromagnetic field in a linear absorptive dielectric medium, is quantized in the framework of the damped polarization model. A Hamiltonian containing a reservoir with continuous degrees of freedom, is proposed. The reservoir minimally interacts with the dielectric polarization and the electromagnetic field. The Lagevin-Schrodinger equation is obtained as the equation of motion of the polarization field. The radiation reaction electromagnetic field is considered. For a homogeneous medium, the equations of motion are solved using the Laplace transformation method.

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arXiv2005

A minimal coupling method for investigating one dimensional dissipative quantum systems

Quantum mechanics of a general one dimensional dissipative system investigated by it's coupling to a Klein-Gordon field as the environment using a minimal coupling method. Heisenberg equation for such a dissipative system containing a dissipative term proportional to velocity obtained. As an example, quantum dynamics of a damped harmonic oscillator as the prototype of some important one dimensional dissipative models investigated consistently. Some transition probabilities indicating the way energy flows between the subsystems obtained.

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arXiv2005

Quantum Charged Non-Linear Nano-String and Quantum Vacuum

The classical and quantum dynamic of a nonlinear chareged vibrating string and its interaction with quantum vacuum field is investigated. Some probability amplitudes for transitions between vacuum field and quantum states of the string are obtained. The effect of nonlinearity on some probability amplitudes is investigated and finally the corect equation for string containing the vacuum and radiation reaction field is obtained.

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arXiv2005

Radiation reaction and quantum damped harmonic oscillator

By taking a Klein-Gordon field as the environment of an harmonic oscillator and using a new method for dealing with quantum dissipative systems (minimal coupling method), the quantum dynamics and radiation reaction for a quantum damped harmonic oscillator investigated. Applying perturbation method, some transition probabilities indicating the way energy flows between oscillator, reservoir and quantum vacuum, obtained

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