Rasoul Roknizadeh - Academia.edu (original) (raw)

Papers by Rasoul Roknizadeh

Optics and Photonics Society of Iran, 2016

Journal of Optics, 2016

In non-magnetic anisotropic media, the behavior of electromagnetic waves depends on the polarizat... more In non-magnetic anisotropic media, the behavior of electromagnetic waves depends on the polarization and direction of the incident light. Therefore, to tame the unwanted wave responses such as polarization dependent reflections, the artificial impedance-matched media are suggested to be used in optical devices like invisibility cloak or super lenses. Nevertheless, developing the impedance-matched media is far from trivial in practice. In this paper, we are comparing the samples of both impedance-matched and non-impedance-matched (non-magnetic) media regarding their electromagnetic response in constructing a well-defined optical metric. In the case of similar anisotropic patterns, we show that the optical metric in an impedance-matched medium for unpolarized light is the same as the optical metric of an electrical birefringent medium when the extraordinary mode is concerned. By comparing the eikonal equation in an empty curved space-time and its counterparts in the medium, we have shown that a non-impedance-matched medium can resemble an optical metric for a particular polarization. As an example of non-impedance-matched materials, we are studying a medium with varying optical axis profile. We show that such a medium can be an alternative to impedance-matched materials in various optical devices.

Optics and Photonics Society of Iran, Feb 15, 2014

In this paper, we suggest a scheme which can produce various types of entangled states of the cav... more In this paper, we suggest a scheme which can produce various types of entangled states of the cavity field. In the scheme, cavities with different time evolution properties are utilized. the cavities are arranged such that, their time evolutions change alternately from JC-to anti-JC-like Hamiltonian. From this configuration, three-partite GHZ states can be generated. At last, it is illustrated that, in the multi-cavity set up, if one prepares all cavities with the same time evolution property, W state can be obtained. An important feature of the proposed scheme is the fact that, the results of the processes are independent of the result of atomic detection.

Foundations of Physics, 2015

In this work we present a construction of coherent states based on "complexifier" method for a sp... more In this work we present a construction of coherent states based on "complexifier" method for a special type of one dimensional nonlinear harmonic oscillator presented by Mathews and Lakshmanan (Q Appl Math 32:215, 1974). We will show the state quantization by using coherent states, or to build the Hilbert space according to a classical phase space, is equivalent to departure from real coordinates to complex ones.

Quantum Information Processing, 2014

In this paper, we suggest a scheme which can produce various types of entangled states of the cav... more In this paper, we suggest a scheme which can produce various types of entangled states of the cavity field. In the scheme, cavities with different circumstances which evolve in time are utilized. It is shown that if two cavities are arranged in a way that, the first cavity is governed by the Jaynes-Cummings (JC) and the other with anti-Jaynes-Cummings (anti-JC) Hamiltonian, entangled EPR state of the cavity field is generated. Also, the proposal can be extended to the multi-cavity case, where the cavities are arranged such that their time evolutions change alternately from JC to anti-JC Hamiltonian. From this configuration, three-and four-partite GHZ states can be generated. At last, it is illustrated that in the multi-cavity set up if one prepares all cavities with the same time evolution property, W state can be produced. An important feature of this scheme is the fact that the result of the processes is independent of the result of atomic detection.

Canadian Journal of Physics, 2004

We show that the well-known Stokes operators, defined as elements of the Jordan–Schwinger map wit... more We show that the well-known Stokes operators, defined as elements of the Jordan–Schwinger map with the Pauli matrices of two independent bosons, are equal to the constants of motion of the two-dimensional isotropic harmonic oscillator. Taking the expectation value of the Stokes operators in a two-mode coherent state, we obtain the corresponding classical Stokes parameters. We show that this classical limit of the Stokes operators, the 2 × 2 unit matrix and the Pauli matrices may be used to expand the polarization matrix. Finally, by means of the constants of motion of the classical two-dimensional isotropic harmonic oscillator, we describe the geometric properties of the polarization ellipse. Our study is restricted to the case of a monochromatic quantized-plane electromagnetic wave that propagates along the z axis.PACS Nos.: 42.50.–p, 42.25.Ja, 11.30.–j

Journal of Physics B, 2016

The dynamics of single-excitation energy transfer in a molecular dimer interacting with a phonon ... more The dynamics of single-excitation energy transfer in a molecular dimer interacting with a phonon bath is studied. Although there are exact numerical solutions for this system, we propose an approach that provides exact analytical results with few electronic degrees of freedom. This approach is based on considering the phonon subsystem in the coherent state representation. Applying this approach, the long-lived coherence time is evaluated in the weak and strong coupling regimes. Moreover, by calculating the quantum entanglement and global quantum discord, the time evolution of quantum correlations is examined. The effects of two parameters, electronic coupling strength and bath temperature, on the energy transfer and quantum correlations are studied. It is shown, in agreement with previous results, that the long-lived coherence time in the weak coupling regime is longer than in the strong coupling regime. Also, the increasing bath temperature gives rise to faster delocalization of en...

Molecular Physics, 2016

ABSTRACT The dynamics of energy transfer in Fenna–Matthews–Olson (FMO) light-harvesting complex i... more ABSTRACT The dynamics of energy transfer in Fenna–Matthews–Olson (FMO) light-harvesting complex interacting with a phonon bath is investigated. In this contribution, by considering the phonon bath as a source of stochastic noise, a new approach is proposed. Also, by calculating the global quantum entanglement and global quantum discord, the time evolution of the quantum correlation during the process is evaluated. The effects of temperature and initial excited state on the energy transfer and the quantum correlation are studied. It is shown, in agreement with the previous results, that the increasing of the temperature gives rise to the faster delocalisation of energy transfer and global quantum entanglement in the FMO complex. The proposed model predicts that the global discord is resistance versus the raising temperature. Furthermore, it is demonstrated that the quantum entanglement with respect to the global quantum discord has a significant role in the process of energy transfer in the FMO complex.

AIP Conference Proceedings, 2007

In this paper, we investigate the relation between the curvature of the physical space and the de... more In this paper, we investigate the relation between the curvature of the physical space and the deformation function of the deformed oscillator algebra using a non-linear coherent states approach.

Modern Physics Letters A, 2014

We study the two-dimensional harmonic oscillator on a noncommutative plane. We show that by intro... more We study the two-dimensional harmonic oscillator on a noncommutative plane. We show that by introducing appropriate Bopp shifts, one can obtain the Hamiltonian of a two-dimensional harmonic oscillator on a sphere according to the Higgs model. By calculating the commutation relations, we show that this noncommutativity is strictly dependent on the curvature of the background space. In other words, we introduce a kind of duality between noncommutativity and curvature by introducing noncommutativity parameters as functions of curvature. Also, it is shown that the physical realization of such model is a charged harmonic oscillator in the presence of electromagnetic field.

International Journal of Theoretical Physics, 2015

In this paper, we study the quantum free particle on the spherical space by applying da costa app... more In this paper, we study the quantum free particle on the spherical space by applying da costa approach for quantum particle on the curved space. We obtain the discrete energy eigenvalues and associated normalized eigenfunctions of the free particle on the sphere. In addition, we introduce the Gazeau-Klauder coherent states of free particle on the sphere. Then, the Gaussian coherent states is defined, which is used to describe the localized particle on the spherical space. Finally, we study the relation between the f-deformed coherent states and Gazeau-Klauder ones for this system.

Journal of Physics A: Mathematical and General, 2004

In this paper, we introduce a new family of photon-added as well as photon-depleted q-deformed co... more In this paper, we introduce a new family of photon-added as well as photon-depleted q-deformed coherent states related to the inverse q-boson operators. These states are constructed via the generalized inverse q-boson operator actions on a newly introduced family of q-deformed coherent states (Quesne C 2002 J. Phys. A: Math. Gen. 35 9213) which are defined by slightly modifying the

International Journal of Modern Physics A, 2012

Generalized (f)-coherent state approach in deformation quantization framework is investigated by ... more Generalized (f)-coherent state approach in deformation quantization framework is investigated by using a *-eigenvalue equation. For this purpose we introduce a new Moyal star product called f-star product, so that by using this *f-eigenvalue equation one can obtain exactly the spectrum of a general Hamiltonian of a deformed system. Eventually the method is supported with some examples.

International Journal of Modern Physics A, 2009

In this paper, by using the Wess–Zumino formalism of noncommutative differential calculus, we sho... more In this paper, by using the Wess–Zumino formalism of noncommutative differential calculus, we show that the concept of nonlinear coherent states originates from noncommutative geometry. For this purpose, we first formulate the differential calculus on a GL p, q(2) quantum plane. By using the commutation relations between coordinates and their interior derivatives, we then construct the two-parameter (p, q)-deformed quantum phase space together with the associated deformed Heisenberg commutation relations. Finally, by applying the obtained results for the quantum harmonic oscillator we construct the associated coherent states, which can be identified as nonlinear coherent states. Furthermore, we show that some of the well-known deformed (nonlinear) coherent states, such as two-parameter (p, q)-deformed coherent states, Maths-type q-deformed coherent states, Phys-type q-deformed coherent states and Quesne deformed coherent states, can be easily obtained from our treatment.

International Journal of Geometric Methods in Modern Physics, 2012

In this paper, by using the nonlinear coherent states approach, we find a relation between the ge... more In this paper, by using the nonlinear coherent states approach, we find a relation between the geometric structure of the physical space and the geometry of the corresponding projective Hilbert space. To illustrate the approach, we explore the quantum transition probability and the geometric phase in the curved space.

The European Physical Journal D, 2005

In this paper we propose a theoretical scheme to show the possibility of generating various famil... more In this paper we propose a theoretical scheme to show the possibility of generating various families of nonlinear (f-deformed) coherent states of the radiation field in a micromaser. We show that these states can be provided in a lossless micromaser cavity under the weak Jaynes-Cummings interaction with intensity-dependent coupling of large number of individually injected two-level atoms in a coherent superposition of the upper and lower states. In particular, we show that the so-called nonlinear squeezed vacuum and nonlinear squeezed first excited states, as well as the even and odd nonlinear coherent states can be generated in a two-photon micromaser.

Canadian Journal of Physics, 2004

By introducing a generalization of the (p, q)-deformed boson oscillator algebra, we establish a t... more By introducing a generalization of the (p, q)-deformed boson oscillator algebra, we establish a two-parameter deformed oscillator algebra in an infinite-dimensional subspace of the Hilbert space of a harmonic oscillator without first finite Fock states. We construct the associated coherent states, which can be interpreted as photon-added deformed states. In addition to the mathematical characteristics, the quantum statistical properties of these states are discussed in detail analytically and numerically in the context of conventional as well as deformed quantum optics. Particularly, we find that for conventional (nondeformed) photons the states may be quadrature squeezed in both cases Q = pq 1 and their photon number statistics exhibits a transition from sub-Poissonian to super-Poissonian for Q 1 they are always sub-Poissonian. On the other hand, for deformed photons, the states are sub-Poissonian for Q > 1 and no quadrature squeezing occurs while for Q

In this paper we consider electromagnetic field quantization in the presence of a dispersive and ... more In this paper we consider electromagnetic field quantization in the presence of a dispersive and absorbing semiconductor quantum dot. By using macroscopic approach and Green's function method, quantization of electromagnetic field is investigated. Interaction of a two-level atom , which is doped in a semiconductor quantum dot, with the quantized field is considered and its spontaneous emission rate is calculated. Comparing with the same condition for an excited atom inside the bulk, it is shown that the spontaneous emission rate of an atom will decrease.

Annals of Physics, 2018

We present a theoretical scheme to simulate quantum field theory in a discrete curved spacetime b... more We present a theoretical scheme to simulate quantum field theory in a discrete curved spacetime based on the Bose-Hubbard model describing a Bose-Einstein condensate trapped inside an optical lattice. Using the Bose-Hubbard Hamiltonian, we first introduce a hydrodynamic presentation of the system evolution in discrete space. We then show that the phase (density) fluctuations of the trapped bosons inside an optical lattice in the superfluid (Mott insulator) state obey the Klein-Gordon equation for a massless scalar field propagating in a discrete curved spacetime. We derive the effective metrics associated with the superfluid and Mott-insulator phases and, in particular, we find that in the superfluid phase the metric exhibits a singularity which can be considered as a the manifestation of an analog acoustic black hole. The proposed approach is found to provide a suitable platform for quantum simulation of various spacetime metrics through adjusting the system parameters.

Optics and Photonics Society of Iran, 2016

Journal of Optics, 2016

In non-magnetic anisotropic media, the behavior of electromagnetic waves depends on the polarizat... more In non-magnetic anisotropic media, the behavior of electromagnetic waves depends on the polarization and direction of the incident light. Therefore, to tame the unwanted wave responses such as polarization dependent reflections, the artificial impedance-matched media are suggested to be used in optical devices like invisibility cloak or super lenses. Nevertheless, developing the impedance-matched media is far from trivial in practice. In this paper, we are comparing the samples of both impedance-matched and non-impedance-matched (non-magnetic) media regarding their electromagnetic response in constructing a well-defined optical metric. In the case of similar anisotropic patterns, we show that the optical metric in an impedance-matched medium for unpolarized light is the same as the optical metric of an electrical birefringent medium when the extraordinary mode is concerned. By comparing the eikonal equation in an empty curved space-time and its counterparts in the medium, we have shown that a non-impedance-matched medium can resemble an optical metric for a particular polarization. As an example of non-impedance-matched materials, we are studying a medium with varying optical axis profile. We show that such a medium can be an alternative to impedance-matched materials in various optical devices.

Optics and Photonics Society of Iran, Feb 15, 2014

In this paper, we suggest a scheme which can produce various types of entangled states of the cav... more In this paper, we suggest a scheme which can produce various types of entangled states of the cavity field. In the scheme, cavities with different time evolution properties are utilized. the cavities are arranged such that, their time evolutions change alternately from JC-to anti-JC-like Hamiltonian. From this configuration, three-partite GHZ states can be generated. At last, it is illustrated that, in the multi-cavity set up, if one prepares all cavities with the same time evolution property, W state can be obtained. An important feature of the proposed scheme is the fact that, the results of the processes are independent of the result of atomic detection.

Foundations of Physics, 2015

In this work we present a construction of coherent states based on "complexifier" method for a sp... more In this work we present a construction of coherent states based on "complexifier" method for a special type of one dimensional nonlinear harmonic oscillator presented by Mathews and Lakshmanan (Q Appl Math 32:215, 1974). We will show the state quantization by using coherent states, or to build the Hilbert space according to a classical phase space, is equivalent to departure from real coordinates to complex ones.

Quantum Information Processing, 2014

In this paper, we suggest a scheme which can produce various types of entangled states of the cav... more In this paper, we suggest a scheme which can produce various types of entangled states of the cavity field. In the scheme, cavities with different circumstances which evolve in time are utilized. It is shown that if two cavities are arranged in a way that, the first cavity is governed by the Jaynes-Cummings (JC) and the other with anti-Jaynes-Cummings (anti-JC) Hamiltonian, entangled EPR state of the cavity field is generated. Also, the proposal can be extended to the multi-cavity case, where the cavities are arranged such that their time evolutions change alternately from JC to anti-JC Hamiltonian. From this configuration, three-and four-partite GHZ states can be generated. At last, it is illustrated that in the multi-cavity set up if one prepares all cavities with the same time evolution property, W state can be produced. An important feature of this scheme is the fact that the result of the processes is independent of the result of atomic detection.

Canadian Journal of Physics, 2004

We show that the well-known Stokes operators, defined as elements of the Jordan–Schwinger map wit... more We show that the well-known Stokes operators, defined as elements of the Jordan–Schwinger map with the Pauli matrices of two independent bosons, are equal to the constants of motion of the two-dimensional isotropic harmonic oscillator. Taking the expectation value of the Stokes operators in a two-mode coherent state, we obtain the corresponding classical Stokes parameters. We show that this classical limit of the Stokes operators, the 2 × 2 unit matrix and the Pauli matrices may be used to expand the polarization matrix. Finally, by means of the constants of motion of the classical two-dimensional isotropic harmonic oscillator, we describe the geometric properties of the polarization ellipse. Our study is restricted to the case of a monochromatic quantized-plane electromagnetic wave that propagates along the z axis.PACS Nos.: 42.50.–p, 42.25.Ja, 11.30.–j

Journal of Physics B, 2016

The dynamics of single-excitation energy transfer in a molecular dimer interacting with a phonon ... more The dynamics of single-excitation energy transfer in a molecular dimer interacting with a phonon bath is studied. Although there are exact numerical solutions for this system, we propose an approach that provides exact analytical results with few electronic degrees of freedom. This approach is based on considering the phonon subsystem in the coherent state representation. Applying this approach, the long-lived coherence time is evaluated in the weak and strong coupling regimes. Moreover, by calculating the quantum entanglement and global quantum discord, the time evolution of quantum correlations is examined. The effects of two parameters, electronic coupling strength and bath temperature, on the energy transfer and quantum correlations are studied. It is shown, in agreement with previous results, that the long-lived coherence time in the weak coupling regime is longer than in the strong coupling regime. Also, the increasing bath temperature gives rise to faster delocalization of en...

Molecular Physics, 2016

ABSTRACT The dynamics of energy transfer in Fenna–Matthews–Olson (FMO) light-harvesting complex i... more ABSTRACT The dynamics of energy transfer in Fenna–Matthews–Olson (FMO) light-harvesting complex interacting with a phonon bath is investigated. In this contribution, by considering the phonon bath as a source of stochastic noise, a new approach is proposed. Also, by calculating the global quantum entanglement and global quantum discord, the time evolution of the quantum correlation during the process is evaluated. The effects of temperature and initial excited state on the energy transfer and the quantum correlation are studied. It is shown, in agreement with the previous results, that the increasing of the temperature gives rise to the faster delocalisation of energy transfer and global quantum entanglement in the FMO complex. The proposed model predicts that the global discord is resistance versus the raising temperature. Furthermore, it is demonstrated that the quantum entanglement with respect to the global quantum discord has a significant role in the process of energy transfer in the FMO complex.

AIP Conference Proceedings, 2007

In this paper, we investigate the relation between the curvature of the physical space and the de... more In this paper, we investigate the relation between the curvature of the physical space and the deformation function of the deformed oscillator algebra using a non-linear coherent states approach.

Modern Physics Letters A, 2014

We study the two-dimensional harmonic oscillator on a noncommutative plane. We show that by intro... more We study the two-dimensional harmonic oscillator on a noncommutative plane. We show that by introducing appropriate Bopp shifts, one can obtain the Hamiltonian of a two-dimensional harmonic oscillator on a sphere according to the Higgs model. By calculating the commutation relations, we show that this noncommutativity is strictly dependent on the curvature of the background space. In other words, we introduce a kind of duality between noncommutativity and curvature by introducing noncommutativity parameters as functions of curvature. Also, it is shown that the physical realization of such model is a charged harmonic oscillator in the presence of electromagnetic field.

International Journal of Theoretical Physics, 2015

In this paper, we study the quantum free particle on the spherical space by applying da costa app... more In this paper, we study the quantum free particle on the spherical space by applying da costa approach for quantum particle on the curved space. We obtain the discrete energy eigenvalues and associated normalized eigenfunctions of the free particle on the sphere. In addition, we introduce the Gazeau-Klauder coherent states of free particle on the sphere. Then, the Gaussian coherent states is defined, which is used to describe the localized particle on the spherical space. Finally, we study the relation between the f-deformed coherent states and Gazeau-Klauder ones for this system.

Journal of Physics A: Mathematical and General, 2004

In this paper, we introduce a new family of photon-added as well as photon-depleted q-deformed co... more In this paper, we introduce a new family of photon-added as well as photon-depleted q-deformed coherent states related to the inverse q-boson operators. These states are constructed via the generalized inverse q-boson operator actions on a newly introduced family of q-deformed coherent states (Quesne C 2002 J. Phys. A: Math. Gen. 35 9213) which are defined by slightly modifying the

International Journal of Modern Physics A, 2012

Generalized (f)-coherent state approach in deformation quantization framework is investigated by ... more Generalized (f)-coherent state approach in deformation quantization framework is investigated by using a *-eigenvalue equation. For this purpose we introduce a new Moyal star product called f-star product, so that by using this *f-eigenvalue equation one can obtain exactly the spectrum of a general Hamiltonian of a deformed system. Eventually the method is supported with some examples.

International Journal of Modern Physics A, 2009

In this paper, by using the Wess–Zumino formalism of noncommutative differential calculus, we sho... more In this paper, by using the Wess–Zumino formalism of noncommutative differential calculus, we show that the concept of nonlinear coherent states originates from noncommutative geometry. For this purpose, we first formulate the differential calculus on a GL p, q(2) quantum plane. By using the commutation relations between coordinates and their interior derivatives, we then construct the two-parameter (p, q)-deformed quantum phase space together with the associated deformed Heisenberg commutation relations. Finally, by applying the obtained results for the quantum harmonic oscillator we construct the associated coherent states, which can be identified as nonlinear coherent states. Furthermore, we show that some of the well-known deformed (nonlinear) coherent states, such as two-parameter (p, q)-deformed coherent states, Maths-type q-deformed coherent states, Phys-type q-deformed coherent states and Quesne deformed coherent states, can be easily obtained from our treatment.

International Journal of Geometric Methods in Modern Physics, 2012

In this paper, by using the nonlinear coherent states approach, we find a relation between the ge... more In this paper, by using the nonlinear coherent states approach, we find a relation between the geometric structure of the physical space and the geometry of the corresponding projective Hilbert space. To illustrate the approach, we explore the quantum transition probability and the geometric phase in the curved space.

The European Physical Journal D, 2005

In this paper we propose a theoretical scheme to show the possibility of generating various famil... more In this paper we propose a theoretical scheme to show the possibility of generating various families of nonlinear (f-deformed) coherent states of the radiation field in a micromaser. We show that these states can be provided in a lossless micromaser cavity under the weak Jaynes-Cummings interaction with intensity-dependent coupling of large number of individually injected two-level atoms in a coherent superposition of the upper and lower states. In particular, we show that the so-called nonlinear squeezed vacuum and nonlinear squeezed first excited states, as well as the even and odd nonlinear coherent states can be generated in a two-photon micromaser.

Canadian Journal of Physics, 2004

By introducing a generalization of the (p, q)-deformed boson oscillator algebra, we establish a t... more By introducing a generalization of the (p, q)-deformed boson oscillator algebra, we establish a two-parameter deformed oscillator algebra in an infinite-dimensional subspace of the Hilbert space of a harmonic oscillator without first finite Fock states. We construct the associated coherent states, which can be interpreted as photon-added deformed states. In addition to the mathematical characteristics, the quantum statistical properties of these states are discussed in detail analytically and numerically in the context of conventional as well as deformed quantum optics. Particularly, we find that for conventional (nondeformed) photons the states may be quadrature squeezed in both cases Q = pq 1 and their photon number statistics exhibits a transition from sub-Poissonian to super-Poissonian for Q 1 they are always sub-Poissonian. On the other hand, for deformed photons, the states are sub-Poissonian for Q > 1 and no quadrature squeezing occurs while for Q

In this paper we consider electromagnetic field quantization in the presence of a dispersive and ... more In this paper we consider electromagnetic field quantization in the presence of a dispersive and absorbing semiconductor quantum dot. By using macroscopic approach and Green's function method, quantization of electromagnetic field is investigated. Interaction of a two-level atom , which is doped in a semiconductor quantum dot, with the quantized field is considered and its spontaneous emission rate is calculated. Comparing with the same condition for an excited atom inside the bulk, it is shown that the spontaneous emission rate of an atom will decrease.

Annals of Physics, 2018

We present a theoretical scheme to simulate quantum field theory in a discrete curved spacetime b... more We present a theoretical scheme to simulate quantum field theory in a discrete curved spacetime based on the Bose-Hubbard model describing a Bose-Einstein condensate trapped inside an optical lattice. Using the Bose-Hubbard Hamiltonian, we first introduce a hydrodynamic presentation of the system evolution in discrete space. We then show that the phase (density) fluctuations of the trapped bosons inside an optical lattice in the superfluid (Mott insulator) state obey the Klein-Gordon equation for a massless scalar field propagating in a discrete curved spacetime. We derive the effective metrics associated with the superfluid and Mott-insulator phases and, in particular, we find that in the superfluid phase the metric exhibits a singularity which can be considered as a the manifestation of an analog acoustic black hole. The proposed approach is found to provide a suitable platform for quantum simulation of various spacetime metrics through adjusting the system parameters.