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arXiv · 0910.2341

Detailed analysis of quantum phase transitions within the $u(2)$ algebra

L. Fortunato·L. Sartori
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Abstract

We analyze in detail the quantum phase transitions that arise in models based on the $u(2)$ algebraic description for bosonic systems with two types of scalar bosons. First we discuss the quantum phase transition that occurs in hamiltonians that admix the two dynamical symmetry chains $u(2)\supset u(1)$ and $u(2)\supset so(2)$ by diagonalizing the problem exactly in the $u(1)$ basis. Then we apply the coherent state formalism to determine the energy functional. Finally we show that a quantum phase transition of a different nature, but displaying similar characteristics, may arise also within a single chain just by including higher order terms in the hamiltonian.

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L. Fortunato, L. Sartori. 2009-10-13. Detailed analysis of quantum phase transitions within the $u(2)$ algebra. https://doi.org/10.1088/0253-6102%2F54%2F4%2F01

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