Physical Review A - Atomic, Molecular, and Optical Physics (10502947)82(4)
Path-integral formalism is employed to study normal and lateral Casimir interactions in a system composed of a dispersive medium surrounded by two semi-infinite ideal conductors. The dispersive medium is modeled by a continuum of harmonic oscillators, and it is shown that for smooth conductors, the normal force at small distances in the presence of a dispersive medium coincides with the original Casimir force, while at large distances, it tends to the original form with a renormalized coefficient. The correction to the normal force because of the roughness on one of the conductors is calculated. When the inner surfaces of both conductors have roughness, the lateral Casimir interaction occurs because of translational symmetry breaking, which is studied. It is shown that both normal and lateral Casimir forces in the presence of a dispersive medium are weaker in comparison with the original one and are proportional to the roughness amplitude squared. The dependence of the normal and lateral interactions on the memory and strength of the dispersive medium is considered. © 2010 The American Physical Society.
Annals of Physics (00034916)326(3)pp. 657-667
By using the path-integral formalism, electromagnetic field in the presence of some linear, isotropic magnetodielectric slabs is quantized and related correlation functions are found. In the framework of path-integral techniques, Casimir force between two infinitely large, parallel and ideal conductors, with a different number of magnetodielectric slabs in between, is obtained by calculating the Green's function corresponding to each geometry. © 2011 Elsevier Inc.
European Physical Journal D (14346060)63(3)pp. 473-482
The role of spin-orbit interaction arises from the Dzyaloshinskii-Moriya anisotropic antisymmetric interaction on the entanglement transfer via an antiferromagnetic XXZ Heisenberg chain is investigated. From symmetrical point of view the XXZ Hamiltonian with Dzyaloshinskii-Moriya interaction can be replaced by a modified XXZ Hamiltonian which is defined by a new exchange coupling constant and rotated Pauli operators. The modified coupling constant and the angle of rotations depend on the strength of Dzyaloshinskii-Moriya interaction. In this paper we study the dynamical behavior of the entanglement propagation through a system which is consist of a pair of maximally entangled spins coupled to one end of the chain. The calculations are performed for the ground state and the thermal state of the chain separately. In both cases the presence of this anisotropic interaction make our channel more efficient. We show for large values of the strength of this interaction a large family of XXZ chains becomes efficient quantum channels for whole values of anisotropy parameter in the region -2 ≤ Δ ≥ 2. © 2011 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
Physical Review A - Atomic, Molecular, and Optical Physics (10502947)83(3)
Starting from a Lagrangian, the electromagnetic field in the presence of a nonlinear dielectric medium is quantized using path-integral techniques, and correlation functions of different fields are calculated. The susceptibilities of the nonlinear medium are obtained, and their relations to coupling functions are determined. Finally, the Casimir energy and force in the presence of a nonlinear medium at finite temperature are calculated. © 2011 American Physical Society.
Physical Review A - Atomic, Molecular, and Optical Physics (10502947)84(6)
Starting from a Lagrangian, an electromagnetic field is quantized in the presence of a medium in thermal equilibrium and also in a medium with time-varying temperature. The vector potential for both equilibrium and nonequilibrium cases is obtained and vacuum fluctuations of the fields are calculated. As an illustrative example, the finite-temperature decay rate and level shift of an atom in a polarizable medium are calculated in this approach. © 2011 American Physical Society.
Physical Review D - Particles, Fields, Gravitation and Cosmology (15502368)84(2)
Bipartite entanglement for states of a noninteracting bosonic or fermionic field in the spacetime of a spherically symmetric black hole of Einstein-Gauss-Bonnet gravity is investigated. Although the initial state is chosen to be maximally entangled as the Bell states, the Hawking-Unruh effect causes the state to be mixed and the entanglement degrades, but with different asymptotic behaviors for the fermionic and bosonic fields. The Gauss-Bonnet term with positive α can play an antigravitation role and so this causes a decrease in the Hawking-Unruh effect and consequently reduces the entanglement degradation. On the other hand, the suggested higher dimensions for the spacetime lead to increased entanglement degradation by increasing the dimension. There is a dramatic difference between the behaviors of the entanglement in terms of the radius of the horizon for a five-dimensional black hole and that for higher dimensional black holes. Both bosonic and fermionic fields entanglements are treated beyond the single-mode approximation. Also, the cases where the accelerating observers located at regions near and far from the event horizon of black hole are studied separately. © 2011 American Physical Society.
International Journal of Theoretical Physics (15729575)51(3)pp. 787-804
Entanglement degradation caused by the Unruh effect is discussed for the tripartite GHZ or W states constructed by modes of a non-interacting quantum field viewed by one inertial observer and two uniformly accelerated observers. For fermionic states, the Unruh effect even for infinite accelerations cannot completely remove the entanglement. However, for the bosonic states, the situation is different and the entanglement vanishes asymptotically. Also, the entanglement is studied for the bipartite subsystems. While for the GHZ states all the bipartite subsystems are identically disentangled, for the W states the bipartite subsystems are somewhat entangled, though, this entanglement can be removed for appropriately accelerated observers. Interestingly, logarithmic negativity as a measure for determining the entanglement of one part of the system relative to the other two parts, is not generally the same for different parts. This means that we encounter tripartite systems where each part is differently entangled to the other two parts. © 2011 Springer Science+Business Media, LLC.
Physical Review A - Atomic, Molecular, and Optical Physics (10502947)86(2)
We investigate the lateral Casimir interaction between two corrugated conductors when they enclose a dielectric slab. The magnitude of the lateral Casimir force can be changed due to the presence of a dielectric slab between them, and it strongly depends on the thickness (d) and dielectric function of the slab and also on the position of the slab with respect to the conductors. In addition, the distance between the conductors (H) and their corrugation wavelengths play important roles in tuning the lateral Casimir interaction. For fixed d and H, quite interestingly, the magnitude of the lateral Casimir force varies when the position of the slab with respect to conductors changes, and it has a maximum when the slab is positioned precisely at the center of the space between the conductors. We find that the interaction decreases when the dielectric constant of the slab increases. © 2012 American Physical Society.
Soltani renani, M.,
Ezatabadipour h., H.,
Jalali j., J.,
Darabi, P.,
Azizi e., E.,
Rashedi, G.R. European Physical Journal D (14346060)67(12)
In this paper,we introduce a system containing of two qubits interacting with a cavity which interacted with a reservoir. Using the Fano technique we will show this system is equivalent with two qubits which are interacting with a common heat bath. We also add a laser field and the behavior of this system is investigated when the qubits are dissipative. In this way we show that the presence of laser field can generate a high entanglement in this system, in other word the pump of energy using the laser field can compensate for the lose of dissipation of qubits. We also show that our system is almost insensible to temperature. © 2013 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
International Journal of Theoretical Physics (15729575)52(12)pp. 4403-4411
The entanglement generation in a two-qubit system interacting with electromagnetic vacuum field and an external local magnetic field is investigated in the framework of the master equation. The time-evolution for the most general density matrix of the two-qubit system is obtained and solved. It is shown that the two-qubit system ends up in an entangled stationary state independent on the initial separable state. © 2013 Springer Science+Business Media New York.
European Physical Journal D (14346060)67(6)
In this paper, entanglement generation by scattering of particles from spin impurities is analyzed. At first, a problem in which an incident particle interacts with an impurity through the Ising and/or Heisenberg interactions is considered. Then, the analysis is extended to investigate the entanglement creation in scattering of particles form two impurities with the same interactions. When the particle is scattered by two impurities, it is shown that a quantum correlation is created between the impurities which is periodic with respect to wavelength of the incident particle. For this case, also it is shown that the Ising interaction is more effective for creating the entanglement between the impurities than the Heisenberg interaction. © EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2013.
European Physical Journal D (14346060)68(11)
Entanglement generation in the one-dimensional collision of two initially uncorrelated spin-1/2 particles is analyzed. It is assumed that the colliding particles interact with each other through a delta potential with a spin-spin coupling strength. Two different approaches are followed. In the first approach, the colliding particles are described by plane waves and in the second one by Gaussian wave packets. It is shown that the collision process create a final state which may be entangled in both momentum and spin spaces. The magnitude of the created entanglement is a function of the potential strength, the initial spin state and the initial momentum of the particles. By changing the initial spin state of the system, an entanglement exchange occurs between the k and spin spaces. Also, the present wave-packet analysis demonstrates, somewhat surprisingly, that initial widths of the wave packets describing the colliding particles play but a minor role for the entanglement generation process. © 2014 EDP Sciences, Società Italiana di Fisica, Springer-Verlag.
European Physical Journal D (14346060)68(4)
Generation of quantum entanglement in scattering of particles from fixed localized spin impurities is investigated. In the suggested approach, the incident particle is described by a Gaussian wave packet with an initial definite width. It is also assumed that the incident particle interacts with the impurities through the Ising and/or Heisenberg interactions. It is shown that the created entanglement is strongly affected by the initial width of the incident wave packet. For an initially well localized wave packet the created entanglement is low. However, as the initial width increases the entanglement grows appreciably and for sufficiently large values of the initial width the present results tend to our previous results for scattering of plane waves from spin impurities. For scattering from a double spin impurity, it is shown that the periodic behavior of the previous results changes significantly. © 2014 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
International Journal of Theoretical Physics (15729575)53(12)pp. 4310-4325
The dynamic behavior of the quantum discord in one-dimensional scattering of a qubit (a spin-1/2 particle) by single and double well-localized fixed spin impurities is investigated theoretically. It is assumed that the incident particle is scattered by the spin impurities through the Ising and/or Heisenberg interactions. These potentials create quantum mechanical correlation between the reflected and transmitted parts of the scattered system and the impurities. It is shown that the incident momentum, strength of the interaction potentials, and the separation between the impurities can be regarded as the control parameters for the quantum discord and concurrence manipulations. In particular, it has been found that the correlations are periodic functions of the wavelength of the incident particle when it is scattered by the double spin impurities. © 2014, Springer Science+Business Media New York.
International Journal of Theoretical Physics (15729575)53(7)pp. 2141-2154
In this work the Hawking-Unruh effect on the quantum entanglement of bosonic field in background of a spherically symmetric black hole of Gauss-Bonnet gravity is investigated beyond the single mode approximation. The entanglement decreases due to Hawking-Unruh effect. However, it has been shown that the dimensions of space time, Gauss-Bonnet term and the parameter β of initial entangled state would be influenced on this degradation. In our investigation, we consider the accelerated observer either near or far from the event horizon and inspect entanglement degradation for them. The mutual information of this bosonic system is also calculated in beyond the single mode approximation and we show that the mutual information will have different behavior when the Hawking temperature increases. © 2013, Springer Science+Business Media New York.
European Physical Journal D (14346060)69(7)
Abstract In this paper, the entanglement and quantum discord created due to a one-dimensional scattering process occurring in a system including two observers, Alice and Bob, is theoretically investigated. In this process, Alice sends a qubit to Bob who is located next to a fixed localized impurity. The impurity is considered as a qubit too. After a Kondo interaction occurred between the components, the incident particle is reflected to Alice by a definite probability. The scattering process generates a correlation between the reflected and the fixed localized particles. We consider different setups for such a scattering process and calculate both the entanglement and the quantum discord created between the ingredients. Both the plane-wave and Gaussian-wave treatments of the incident particle are examined. The dependence of the created entanglement on the initial width of the incident Gaussian wave packet is explored. It is shown that setting the impurity between the incident particle and an infinite potential wall is an effective way to produce a considerable entanglement in the final state. © 2015 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
European Physical Journal D (14346060)69(7)
Abstract We propose a method to generate stationary entanglement between two macroscopic vibrating elements (micro-mechanical resonators (MRs)), via a transmission line resonator (TLR) field mode, where the MRs are coupled to the TLR capacitively. In this paper two situations are studied; (i) a driving on TLR field with an external microwave pulse, (ii) driving on TLR field and simultaneous driving on two MRs. Here, the entanglement is quantified by the logarithmic negativity. As our proposed system is a continuous variable system, the logarithmic negativity is defined in terms of covariance matrix. We have shown that the second case leads to much stronger entanglement, even at a few milli Kelvin temperatures. © 2015 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
Iranian Journal of Physics Research (16826957)15(3)pp. 317-335
In this work, we generalize the entanglement of three-qbit Bosonic systems beyond the single-mode approximation when one of the observers is accelerated. For this purpose, we review the effects of acceleration on field modes and quantum states. The single-mode approximation and beyond the single-mode approximation methods are introduced. After this brief introduction, the main problem of this paper, tripartite entanglement of bosonic systems in a noninertial frame beyond the single- mode approximation is investigated. The tripartite entangled states have different classes with GHZ and W states being most important. Here, we choose π-tangle as a measure of tripartite entanglement. If the three parties share GHZ state, the corresponding π-tangle will increase by increasing acceleration for some Unruh modes. This phenomenon, increasing entanglement, has never been observed in the single-mode approximation for bosonic case. Moreover, the π-tangle dose not exhibit a monotonic behavior with increasing acceleration. In the infinite acceleration limit, the π-tangle goes to different nonzero values for distinct Unruh modes. Unlike GHZ state, the entanglement of the W state shows only monotonically increasing and decreasing behaviors with increasing acceleration. Also, the entanglement for all possible choices of Unruh modes approaches only 0.176 in the high acceleration limit. Therefore, according to the quantum entanglement, there is no distinction between the single-mode approximation and beyond the single-mode approximation methods in this limit. © 2015, Iranian Journal of Physics Research. All rights reserved.
Quantum Information Processing (15700755)15(6)pp. 2377-2391
Scattering of a ballistic electron by the quantum-dot spin qubits fixed in a graphene nanoribbon is investigated theoretically. Two simple cases are investigated in details: scattering from a static quantum dot and scattering from two static quantum dots located at a fixed distance from each other. For the first case, it is shown that the Klein tunneling in a graphene sheet leads to a final entangled state for the reflected and/or transmitted electrons. The amount of the generated entanglement through the scattering process is a function of the incident angle for the ballistic electrons. For the second case, it is shown that the created correlation between the quantum dots is a periodic function of their distance. For frontal incident electrons in both cases, there is not any reflection and the Klein tunneling effect leads to a final well-correlated state for the scattering system. © 2016, Springer Science+Business Media New York.
European Physical Journal D (14346060)70(12)
Abstract: Electromagnetic field quantization, in the presence of two semi-infinite dielectrics withmoving interface, is investigated in 1 +1-dimensional space-time. The moving interface is modelled for smalldisplacements and the field equation is solved perturbatively. Input-output relations andspectral distribution of emitted photons are obtained and the effect of small transitionsthrough the interface discussed. Graphical abstract: [Figure not available: see fulltext.] © 2016, EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
Quantum Information Processing (15700755)15(10)pp. 4219-4236
Entanglement generation due to low-energy scattering of the transporting electrons in an electronic waveguide by a quantum dot magnetic impurity is theoretically investigated. The transverse confining potential of the waveguide is considered as a two-dimensional harmonic potential, and the interaction of the electron with the impurity is described by a zero-range pseudopotential modulated by an Ising or a Heisenberg spin interaction. Our calculation shows that the scattering process leads to creation of a considerable amount of entanglement in the state of the reflected and transmitted electrons. The situation is extended to the scattering of the electrons by two well-separated magnetic impurities localized on the nanowire axis. It is shown that the scattering process causes the magnetic impurities embedded in the nanowire to share their quantum information; subsequently, they can be entangled by spin interaction with the injected electron. The created entanglement between the impurities is calculated and discussed. It is shown that the exact three-dimensional problem can be approximated as a one-dimensional problem under certain circumstances. The approximate results are compared to exact calculations and discussed. © 2016, Springer Science+Business Media New York.
Language Related Research (23223081)8(8)pp. 207-230
Today, syntagmatic and paradigmatic analyses are widely applied by literature researchers and experts as principal methods in understanding and interpretation of religious texts. Taking syntagmatic and paradigmatic analyses into consideration, this research seeks to explore the explicit and implicit meanings of the Arabic term (Doon), literally translated as “other than, instead of, besides, and apart from”, in the Holy Quran. It also aims to determine how much attention Quran translators have paid to the meanings of the term and in transferring them into the target language, namely Persian. The study, conducted based on structural semantics and using descriptive –analytic research methodology, has found that the term (Doon) has various meanings and functions in the Holy Quran, but in some cases, translators have failed to render them correctly. The original meaning of the term is “other than and inferior” which is seen almost in all phrases and lexical combinations in the Holy Book. Therefore, for instance, the phrase which has been transplanted as “other than, besides and apart from Allah” in famous translations, can be rendered as “[someone/something] other as Allah that is inferior”. (Inferior)" or " (Inferior to)" have been used as equivalents to (Doon) in old Persian translations of the Quran which closely correspond with the denotation of the Arabic word,since they contain both the sense of “other than” and “inferior”. However, (Doon) can bear different meanings in different contexts. © 2017, Tarbiat Modares University. All rights reserved.
European Physical Journal D (14346060)71(1)
Abstract: Motivated by the problem of Casimir energy, we investigate the idea of usinginhomogeneity of surfaces instead of their corrugation, which leads to Casimir interactionbetween two inhomogeneous semi-transparent concentric cylinders. Using the multiplescattering method, we study the Casimir energy and torque between the cylinders withdifferent potentials subjected to Dirichlet boundary conditions, both in weak and strongcoupling regimes. We also extend our formalism to the case of two inhomogeneousdielectrics in a weak coupling regime. Graphical abstract: [Figure not available: see fulltext.] © 2017, EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
Physical Review A (24699934)95(2)
The normal and the lateral Casimir interactions between corrugated ideal metallic plates in the presence of an amplifying or an absorptive dielectric slab is studied by the path-integral quantization technique. The effect of the amplifying slab, which is located between corrugated conductors, is to increase the normal and lateral Casimir interactions, while the presence of the absorptive slab diminishes the interactions. These effects are more pronounced if the thickness of the slab increases and, also, if the slab comes closer to one of the bounding conductors. When both bounding ideal conductors are flat, the normal Casimir force is nonmonotonic in the presence of the amplifying slab and the system has a stable mechanical equilibrium state, while the force is attractive and is weakened by intervening the absorptive dielectric slab in the cavity. Upon replacing one of the flat conductors with a flat ideal permeable plate the force becomes nonmonotonic and the system has an unstable mechanical equilibrium state in the presence of either an amplifying or an absorptive slab. When the left-side plate is a conductor and the right one is permeable, the force is nonmonotonic in the presence of a double-layer dissipative-amplifying dielectric slab with a stable mechanical equilibrium state, while it is purely repulsive in the presence of a double-layer amplifying-dissipative dielectric slab. © 2017 American Physical Society.
Journal of Physics Condensed Matter (09538984)31(21)
Zigzag phosphorene nanoribbons have quasi-flat band edge modes entirely detached from bulk states. We analytically study the electronic transport through such edge states in the presence of a localized defect for semi-infinite and finite ribbon widths. Using the tight-binding model, we derive analytical expressions for the Green's function and transmission amplitude of both pristine and defective nanoribbons. We find that the transmission of ribbons with both semi-infinite and finite width is sensitive to the location of a single impurity defect with respect to the edge. By the presence of an impurity on the outermost edge site of the ribbon, the transmission through the edge channel, similar to a one-dimensional chain, strongly suppresses for the entire energy spectrum of the quasi-flat band. In contrast, the transmission of low-energy (E ≈ 0) states, is robust as the impurity is moved one position far away from the edge on the same sub-lattice. The analytical calculations are also complemented by exact numerical transport computations using the Landauer approach. © 2019 IOP Publishing Ltd Printed in the UK.
International Journal Of High Risk Behaviors And Addiction (2251872X)8(2)
Context: This research article is about the role of educational teachings of religion in the prevention of high-risk social behaviors, based on Imam Sadeq's (peace be upon him) biography and Hadiths considering the relationship between religion and high-risk behaviors. Evidence Acquisition: In this research, using descriptive-analytical method, on one hand, the relationship between religion and high-risk behaviors in published articles, especially PubMed, has been considered and, onthe other hand, by reviewing about twenty thousand narratives of biography and Hadiths of Imam Sadiq (peace be upon him), the most important examples of high-risk behaviors referred by him are discussed. Results: This survey emphasized the acquisition of religious teachings, the study and consideration on religion, familiarity with God, necessity of marriage, halal occupation, moderate behavior, meeting with friends and strengthening them, attention to food, planning, indirect notification, and appropriate punishment are some of the most important preventive educational teachings of high-risk behaviors in the speech and behavior of Imam Sadiq (peace be upon him), which have been confirmed in various internal and external research. Conclusions: The educational teachings of religion can make it possible for people in the society to tend less to exhibit social harms and, consequently, high-risk behavior, ensuring health for the individual, family, and finally, the society by establishing a constructive meanwhile, preventive role in everybody. © 2019, Author(s).
Europhysics Letters (02955075)125(6)
Transport of the edge-state electrons along zigzag phosphorene nanoribbons in the presence of two impurities/vacancies is analytically investigated. Considering the places of the defects, a number of different situations are examined. When both defects are placed on the edge zigzag chain, as is expected, by changing the energy of the traveling electrons the electrical conductance exhibits a resonance behavior. In this case, for two vacancies the observed resonant peaks become extremely sharp. An amazing behavior is seen when the second vacancy is located along an armchair chain while the first is placed at the intersection of the edge zigzag and this armchair chain. In this case, in a considerable range of energy, the conductance is strongly strengthened. In fact the presence of the second vacancy creates a shielded region around the first vacancy, consequently, the traveling wave bypasses this region and enhances the conductance. The analytical results are compared with numerical simulations showing very good agreement. © 2019 EPLA.
