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M. A. Jafarizadeh

Publications and source records attributed to M. A. Jafarizadeh.

At least 37 records · Page 2Linked to original sources
arXiv2012

Level Statistics of SU(3)-SU(3)* Transitional Region

The level statistics of SU(3)-SU(3)* transitional region of IBM is described by the nearest neighbor spacing distribution statistics. The energy levels are determined by using the SO(6)representation of eigenstates. By employing the MLE technique, the parameter of Abul-Magd distribution is estimated where suggest less regular dynamics for transitional region in compare to dynamical symmetry limits. Also, the O(6)dynamical symmetry which is known as the critical point of this transitional region, describes a deviation to more regular dynamics.

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arXiv2012

Investigation of Level Statistics by Generalized Brody Distribution and Maximum Likelihood Estimation Method

With generalizing the Brody distribution to include the Poisson, GOE and GUE limits and with employing the maximum likelihood estimation technique, the spectral statistics of different sequences were considered in the nearest neighbor spacing statistics framework. The ML-based estimated values for the parameters of generalized distribution propose more precisions in compare to the predictions of other distributions. The transition in the level spacing statistics of different systems were described by the distances of ML-based predictions for generalized distribution to three limits which determined by KLD measures.

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arXiv2012

Level Statistics of Stable and Radioactive Nuclei

The spectral statistics of nuclei undergo through the major forms of radioactive decays ((α)(β^-), and(β^+) (or EC)) and also stable nuclei are investigated. With employing the MLE technique in the nearest neighbor spacing framework, the chaoticity parameters are estimated for sequences prepared by all the available empirical data. The ML-based estimated values propose a deviation to more regular dynamics in sequences constructed by stable nuclei in compare to unstable ones. In the same mass regions, nuclei transmitted through (α)decay explore less regularity in their spectra in compare to other radioactive nuclei.

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arXiv2012

A Description of Hg (200-204)isotopes in the SU(3)<->SU(3)* Transitional Region

With employing the SO(6)representation of eigenstates, the energy spectra and quadrupole transition rates of SU(3)<->SU(3)* transition region are considered for systems with total boson number N=2,3,4. The apparent level crossing and significant variations in the transition rates for X=0, namely, the critical point of transitional Hamiltonian, suggest a phase transition between these limits. The parameter free (up to overall scale factors) predictions for spectra and B(E2)rates by X=0are found to be in good agreement with those for nuclei provide empirical evidences for O(6)dynamical symmetry, namely Hg(200-204)isotopes.

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arXiv2012

An Affine SU(1,1)Description of Even-Even Cd (106-122) Isotopes in the Transitional Region of IBM

In this paper, the properties of Cd(106-122)isotopes are considered in the U(5)-SO(6)transitional region of IBM1. With employing a transitional Hamiltonian which is based on affine SU(1,1)Lie Algebraic technique, the energy levels and B(E2)transition rates are calculated. The results are compared with the most recent experimental values where an acceptable degree of agreement is achieved. Also, the energy ratios, control parameters and empirical two neutron separation energies suggest spherical to gamma soft shape transitions in these nuclei where the Cd (114,122)nuclei are considered as the best candidates for the E(5)critical symmetry.

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arXiv2012

Investigation of Shape Phase Transition in theU(5)-SO(6)Transitional Region by Catastrophe Theory and Critical Exponents of some Quantities

In the present paper, by employing the formation of the Catastrophe Theory, the phase transition points for U(5)-SO(6) transitional Hamiltonian, which is defined according to the affineSU(1,1)algebra are investigated. The energy surfaces of the even-even isotopes of Ru and Pd nuclei are considered and special isotopes which are the best candidates for theE(5) critical point are identified. Also, the analogy between the critical exponents of ground-state quantum phase transition and Landau values for the critical exponents of thermodynamic phase transition are described.

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arXiv2012

Spectral fluctuation properties of spherical nuclei

The spectral fluctuation properties of spherical nuclei are considered by use of NNSD statistic. With employing a generalized Brody distribution included Poisson, GOE and GUE limits and also MLE technique, the chaoticity parameters are estimated for sequences prepared by all the available empirical data. The ML-based estimated values and also KLD measures propose a non regular dynamic. Also, spherical odd-mass nuclei in the mass region, exhibit a slight deviation to the GUE spectral statistics rather than the GOE.

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arXiv2011

Non-parametric Estimation approach in statistical investigation of nuclear spectra

In this paper, Kernel Density Estimation (KDE) as a non-parametric estimation method is used to investigate statistical properties of nuclear spectra. The deviation to regular or chaotic dynamics, is exhibited by closer distances to Poisson or Wigner limits respectively which evaluated by Kullback-Leibler Divergence (KLD) measure. Spectral statistics of different sequences prepared by nuclei corresponds to three dynamical symmetry limits of Interaction Boson Model(IBM), oblate and prolate nuclei and also the pairing effect on nuclear level statistics are analyzed (with pure experimental data). KD-based estimated density function, confirm previous predictions with minimum uncertainty (evaluated with Integrate Absolute Error (IAE)) in compare to Maximum Likelihood (ML)-based method. Also, the increasing of regularity degrees of spectra due to pairing effect is reveal.

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arXiv2011

Nonlinear Electron Heat Conduction Equation and Self similar method for 1-D Thermal Waves in Laser Heating of Solid Density DT Fuel

Electron heat conduction is one of the ways that energy transports in laser heating of fusible target material. The aim of Inertial Confinement Fusion (ICF) is to show that the thermal conductivity is strongly dependent on temperature and the equation of electron heat conduction is a nonlinear equation. In this article, we solve the one-dimensional (1-D) nonlinear electron heat conduction equation with a self-similar method (SSM). This solution has been used to investigate the propagation of 1-D thermal wave from a deuterium-tritium (DT) plane source which occurs when a giant laser pulse impinges onto a DT solid target. It corresponds to the physical problem of rapid heating of a boundary layer of material in which the energy of laser pulse is released in a finite initial thickness.

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arXiv2011

Investigation of level spacing distribution of nuclear energy levels by maximum likelihood estimation method

The nearest neighbor spacing distribution (NNSD) is one of common methods in statistical analysis of nuclear energy levels. In this paper, we have proposed Maximum Likelihood Estimation (MLE) method to evaluate parameter of (NNSD)'s which explain chaotic and regular behavior of nuclear systems .Also with Cramer-Rao Lower Bound (CRLB) will obtain decreasing of uncertainty for our results in compare to previous methods. We calculate these parameters for different mass groups and nuclei with special values of deformation parameter, and also for nuclei with IBM's three dynamical symmetries and transitional regions between these three limits and confirm theoretical predictions even in cases where the small size of data don't allow exact conclusions with previous methods . We obtain better consistent of our results with Poisson and Wigner(GOE) distributions with Kullback-Leibeller divergence.

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arXiv2011

Minimum-error discrimination between two sets of similarity-transformed quantum states

Using the necessary and sufficient conditions, minimum error discrimination among two sets of similarity transformed equiprobable quantum qudit states is investigated. In the case that the unitary operators are generating sets of two irreducible representations, the optimal set of measurements and the corresponding maximum success probability of discrimination are determined in closed form. In the case of reducible representations, there exists no closed-form formula in general, but the procedure can be applied in each case accordingly. Finally, we give the maximum success probability of optimal discrimination for some important examples of mixed quantum states, such as qubit states together with three special cases and generalized Bloch sphere m-qubit states.

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arXiv2011

Level spacing of U(5) \leftrightarrow SO(6) transitional region with maximum likelihood estimation method

In this paper,a systematic study of quantum phase transition within U(5) \leftrightarrow SO(6) limits is presented in terms of infinite dimensional Algebraic technique in the IBM framework. Energy level statistics are investigated with Maximum Likelihood Estimation (MLE) method in order to characterize transitional region. Eigenvalues of these systems are obtained by solving Bethe-Ansatz equations with least square fitting processes to experimental data to obtain constants of Hamiltonian. Our obtained results verify the dependence of Nearest Neighbor Spacing Distribution's (NNSD) parameter to control parameter (c_{s}) and also display chaotic behavior of transitional regions in comparing with both limits. In order to compare our results for two limits with both GUE and GOE ensembles, we have suggested a new NNSD distribution and have obtained better KLD distances for the new distribution in compared with others in both limits. Also in the case of N\to\infty, the total boson number dependence displays the universality behavior, namely NNSD tends to Poisson limit for every values of control parameter.

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arXiv2011

Minimum error discrimination between similarity transformed quantum states

Using the known necessary and sufficient conditions for minimum error discrimination (MED), first it is shown that a Helstrom family of ensembles is equivalent to these conditions and then by a convex combination of the initial states (the states which we try to discriminate them) and the corresponding conjugate states, a more suitable and convenient form for the MED conditions is extracted, so that optimal set of measurements and corresponding optimal success probability of discrimination can be determined. Then, using the introduced identity, MED between N similarity transformed equiprobable quantum states is investigated. As a special case, MED between the so called group covariant or symmetric states is considered.

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arXiv2011

Generating GHZ state in 2m-qubit spin network

We consider a pure 2m-qubit initial state to evolve under a particular quantum me- chanical spin Hamiltonian, which can be written in terms of the adjacency matrix of the Johnson network J(2m;m). Then, by using some techniques such as spectral dis- tribution and stratification associated with the graphs, employed in [1, 2], a maximally entangled GHZ state is generated between the antipodes of the network. In fact, an explicit formula is given for the suitable coupling strengths of the hamiltonian, so that a maximally entangled state can be generated between antipodes of the network. By using some known multipartite entanglement measures, the amount of the entanglement of the final evolved state is calculated, and finally two examples of four qubit and six qubit states are considered in details.

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arXiv2010

Constructing Entanglement Witness Via Real Skew-Symmetric Operators

In this work, new types of EWs are introduced. They are constructed by using real skew-symmetric operators defined on a single party subsystem of a bipartite dxd system and a maximal entangled state in that system. A canonical form for these witnesses is proposed which is called canonical EW in corresponding to canonical real skew-symmetric operator. Also for each possible partition of the canonical real skew-symmetric operator corresponding EW is obtained. The method used for dxd case is extended to d1xd2 systems. It is shown that there exist Cd2xd1 distinct possibilities to construct EWs for a given d1xd2 Hilbert space. The optimality and nd-optimality problem is studied for each type of EWs. In each step, a large class of quantum PPT states is introduced. It is shown that among them there exist entangled PPT states which are detected by the constructed witnesses. Also the idea of canonical EWs is extended to obtain other EWs with greater PPT entanglement detection power.

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arXiv2010

Entanglement Witnesses and Characterizing Entanglement Properties of Some PPT States

On the basis of linear programming, new sets of entanglement witnesses (EWs) for 3x3 and 4x4 systems are constructed. In both cases, the constructed EWs correspond to the hyperplanes contacting, without intersecting, the related feasible regions at line segments and restricted planes respectively. Due to the special property of the contacting area between the hyper-planes and the feasible regions, the corresponding hyper-planes can be turned around the contacting area throughout a bounded interval and hence create an infinite number of EWs. As these EWs are able to detect entanglement of some PPT states, they are non-decomposable (nd-EWs).

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arXiv2010

Perfect state transfer over interacting boson networks associated with group schemes

It is shown how to perfectly transfer an arbitrary qudit state in interacting boson networks. By defining a family of Hamiltonians related to Bose-Hubbard model, we describe a possible method for state transfer through bosonic atoms trapped in these networks with different kinds of coupling strengths between them. Particularly, by taking the underlying networks of so called group schemes as interacting boson networks, we show how choose suitable coupling strengths between the nodes, in order that an arbitrary qudit state be transferred from one node to its antipode, perfectly. In fact, by employing the group theory properties of these networks, an explicit formula for suitable coupling strengths has been given in order that perfect state transfer (PST) be achieved. Finally, as examples, PST on the underlying networks associated with cyclic group C2m, dihedral group D2n, Clifford group CL(n), and the groups U6n and V8n has been considered in details. Keywords: Bose-Hubbard Hamiltonian, Interacting boson networks, Perfect state transfer (PST), Qudit state, Underlying networks, Group schemes PACs Index: 01.55.+b, 02.10.Yn

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