Simple qubit systems in bosonic baths.
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Date
2010
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Abstract
The study is focused on the thermal entanglement of spin chains. Chains consisting of two
and three qubits are considered. These chains are considered open because they are coupled to
bosonic baths at different temperatures. The baths represent the environment. The dynamics
of these open systems are examined as are the effects of different parameters - such as bath
temperature - on the entanglement of the spins. The measure of entanglement used in these
cases is the concurrence. Comparisons are made between a model that assumes a strong spinspin
interaction and one that assumes a weak one. In all these cases, analytical solutions for
the system dynamics are presented. It is found that at large times, all systems converge to
a state that depends only on bath temperature. It is also found that increases in bath temperatures
diminish the entanglement between spins and that at high enough temperatures the
entanglement vanishes altogether. The time and temperature dependence of the entanglement
is different for the two models that are studied.
Description
Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2010.
Keywords
Quantum theory., Wave-particle duality., Quantum chemistry., Theses--Physics.