The role of various types of defects in establishing the magnetic properties of the C60-based polymers and the single-wall carbon nanotubes is investigated. Comparing the role of carbon vacancies, and that of substitutional impurity atoms X X=N, B, O, Si, P, and S in establishing a magnetic ground state it is found that the impurity X atoms promote the spin density delocalization, whereas its l...

We study the interaction-induced localization – the so-called self-trapping – of a neutral impurity atom immersed in a homogeneous Bose-Einstein condensate (BEC). Based on a Hartree description of the BEC we show that – unlike repulsive impurities – attractive impurities have a singular ground state in 3d and shrink to a point-like state in 2d as the coupling approaches a critical value β⋆. Mor...

Bose-Einstein condensation is the macroscopic occupation of a single quantum state. In bulk liquid Helium, most theoretical calculations[1] agree that, in the limit of zero temperature, roughly 10% of the Helium atoms are condensed in the ground state. For recently observed atomic condensates in Rb [2], Li [3] and Na [4], nearly 100% condensation is expected because of their low density. This c...

We study the two qubits Heisenberg XX chain with magnetic impurity in the presence of the external magnetic field and calculate the optimal fidelity of standard teleportation via the thermal equilibrium state. It is found that the combined influence of magnetic impurity and external magnetic field can increase the critical temperatures of entanglement and quantum teleportation without limit. Th...

In our recent paper [O. Gamayun, O. Lychkovskiy, and V. Cheianov, Phys. Rev. E 90, 032132 (2014)] we studied the dynamics of a mobile impurity particle weakly interacting with the Tonks-Girardeau gas and pulled by a small external force F. Working in the regime when the thermodynamic limit is taken prior to the small force limit, we found that the Bloch oscillations of the impurity velocity are...

The one-dimensional problem of N particles with contact interaction in the presence of a tunable transmitting and reflecting impurity is investigated along the lines of the coordinate Bethe ansatz. As a result, the system is shown to be exactly solvable by determining the eigenfunctions and the energy spectrum. The latter is given by the solutions of the Bethe ansatz equations which we establis...

We study the competition between Kondo physics and dissipation within an Anderson model of a magnetic impurity level that hybridizes with a metallic host and is also coupled, via the impurity charge, to the displacement of a bosonic bath having a spectral density proportional to s. As the impurity-bath coupling increases from zero, the effective Coulomb interaction between two electrons in the ...

The magnetic polarization induced by nonmagnetic impurities such as Zn in high Tc cuprate compounds is studied by the variational Monte Carlo simulation. The variational wave function is constructed from the eigenstates obtained from Bogoliubov de Gennes mean field Hamiltonian for the twodimensional t − J model. A Jastrow factor is introduced to account for the induced magnetic moment and the r...

In this paper, the effect of pressure, temperature and impurity on the energylevels, binding energy, linear and nonlinear optical properties of a modified Gaussianquantum dot are studied. In this regard, the finite element method is employed to solvethe single electron Schrodinger equation in the effective mass approximation with andwithout impurity at the center of the dot. In addition, the en...