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Spin Chains (spin + chain)
Selected AbstractsCrystal growth and magnetic properties of the copper coordination polymer [Cu(µ -C2O4)(4-aminopyridine)2(H2O)]nCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2007A. V. Prokofiev Abstract In this paper, we consider various ways of crystal growth of the polymer [Cu(µ -C2O4)(4-aminopyridine)2(H2O)]n. Single crystals of the size of 1.5×1.5×0.2 mm3 have been grown by a slow diffusion technique from solutions of the monoammine copper complex and of the mixture of potassium oxalate and aminopyridine with the stoichiometric ratio. Magnetic susceptibility and ESR measurements have been performed on single crystals large enough for investigating anisotropic properties. The susceptibility can be well described within the model of a Heisenberg antiferromagnetic spin chain. The magnetic measurements reveal a small concentration of paramagnetic moments reflecting the high quality of the single crystals. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Green's function and excitation spectrum of finite latticesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2006S. Cojocaru Abstract New analytical results are obtained for the Green's function of a finite one-dimensional lattice with nearest neighbor interaction using discrete Fourier transform. The method offers an alternative to the Bethe Ansatz, but does not require any a priori assumption on the form of the wavefunction. This makes it suitable for extensions to nano-ferromagnets of higher dimensions. Solutions of the Heisenberg spin chain with periodic and open boundary conditions are considered as examples. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Entanglement of spin chains with general boundaries and of dissipative systemsANNALEN DER PHYSIK, Issue 7-8 2009T. Stauber Abstract We analyze the entanglement properties of spins (qubits) close to the boundary of spin chains in the vicinity of a quantum critical point and show that the concurrence at the boundary is significantly different from the one of bulk spins. We also discuss the von Neumann entropy of dissipative environments in the vicinity of a (boundary) critical point, such as two Ising-coupled Kondo-impurities or the dissipative two-level system. Our results indicate that the entanglement (concurrence and/or von Neumann entropy) changes abruptly at the point where coherent quantum oscillations cease to exist. The phase transition modifies significantly less the entanglement if no symmetry breaking field is applied and we argue that this might be a general property of the entanglement of dissipative systems. We finally analyze the entanglement of an harmonic chain between the two ends as function of the system size. [source] Entanglement of spin chains with general boundaries and of dissipative systemsANNALEN DER PHYSIK, Issue 7-8 2009T. Stauber Abstract We analyze the entanglement properties of spins (qubits) close to the boundary of spin chains in the vicinity of a quantum critical point and show that the concurrence at the boundary is significantly different from the one of bulk spins. We also discuss the von Neumann entropy of dissipative environments in the vicinity of a (boundary) critical point, such as two Ising-coupled Kondo-impurities or the dissipative two-level system. Our results indicate that the entanglement (concurrence and/or von Neumann entropy) changes abruptly at the point where coherent quantum oscillations cease to exist. The phase transition modifies significantly less the entanglement if no symmetry breaking field is applied and we argue that this might be a general property of the entanglement of dissipative systems. We finally analyze the entanglement of an harmonic chain between the two ends as function of the system size. [source] | ||||||||||