Zobrazeno 1 - 10
of 109
pro vyhledávání: '"Büttner, Helmut"'
Publikováno v:
Phys. Rev. B 73, 214407 (2006) (14 pages)
We consider the spin-1/2 anisotropic XY chain in a transverse (z) field with the Dzyaloshinskii-Moriya interaction directed along z-axis in spin space to examine the effect of the Dzyaloshinskii-Moriya interaction on the zz, xx and yy dynamic structu
Externí odkaz:
http://arxiv.org/abs/0712.3361
Information and entropy in quantum Brownian motion: Thermodynamic entropy versus von Neumann entropy
We compare the thermodynamic entropy of a quantum Brownian oscillator derived from the partition function of the subsystem with the von Neumann entropy of its reduced density matrix. At low temperatures we find deviations between these two entropies
Externí odkaz:
http://arxiv.org/abs/0710.1716
Autor:
Gaul, Christopher, Büttner, Helmut
Publikováno v:
Phys. Rev. E 76, 011111 (2007)
We investigate the mechanism of heat conduction in ordered and disordered harmonic onedimensional chains within the quantum mechanical Langevin method. In the case of the disordered chains we find indications for normal heat conduction which means th
Externí odkaz:
http://arxiv.org/abs/quant-ph/0702157
Autor:
Endrejat, Jochen, Buettner, Helmut
We compare the polynomial invariants for four qubits introduced by Luque and Thibon, PRA {\bf 67}, 042303 (2003), with optimized Bell inequalities and a combination of two qubit concurrences. It is shown for various parameter dependent states from di
Externí odkaz:
http://arxiv.org/abs/quant-ph/0606215
Autor:
Endrejat, Jochen, Buettner, Helmut
Within a special multi-coin quantum walk scheme we analyze the effect of the entanglement of the initial coin state. For states with a special entanglement structure it is shown that this entanglement can be meausured with the mean value of the walk,
Externí odkaz:
http://arxiv.org/abs/quant-ph/0507184
We study the influence of entanglement on the relation between the statistical entropy of an open quantum system and the heat exchanged with a low temperature environment. A model of quantum Brownian motion of the Caldeira-Leggett type - for which a
Externí odkaz:
http://arxiv.org/abs/cond-mat/0408536
Publikováno v:
Phys. Rev. A 68, 032318 (2003)
Analytical expressions for the entanglement measures concurrence, i-concurrence and 3-tangle in terms of spin correlation functions are derived using general symmetries of the quantum spin system. These relations are exploited for the one-dimensional
Externí odkaz:
http://arxiv.org/abs/quant-ph/0305108
Autor:
Bussmann-Holder, Annette, Bishop, Alan R., Buettner, Helmut, Egami, Takeshi, Micnas, Roman, Mueller, K. Alex
The phase diagram of superconducting copper oxides is calculated as a function of doping based on a theory of dynamic stripe induced superconductivity. The two major conclusions from the theory and the numerical analysis are that T* (the pseudogap on
Externí odkaz:
http://arxiv.org/abs/cond-mat/0104089
Autor:
Büttner, Helmut
Publikováno v:
Zeitschrift für Germanistik, 2005 Jan 01. 15(3), 523-535.
Externí odkaz:
https://www.jstor.org/stable/23978669
Publikováno v:
In Canadian Journal of Ophthalmology/Journal canadien d'ophtalmologie February 2007 42(1):131-133