Motivated by an analogy with the spin anisotropies in the quantum XY chain and its reformulation in terms of spin-less Majorana fermions, its bosonic analogue, the spin-anisotropic quantum spherical model, is introduced. The exact solution of the model permits to analyse the influence of the spin-anisotropy on the phase diagram and the universality of the critical behaviour in a new way, since the interactions of the quantum spins and their conjugate momenta create new effects. At zero temperature, a quantum critical line is found, which is in the same universality class as the thermal phase transition in the classical spherical model in $d+1$ dimensions. The location of this quantum critical line shows a re-entrant quantum phase transition for dimensions $1
|Journal||Journal of Statistical Mechanics: Theory and Experiment|
|Publication status||Published - 7 Jul 2015|
Bibliographical noteThis is the Accepted Manuscript version of an article accepted for publication in Journal of Statistical Mechanics: Theory and Experiment IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at 10.1088/1742-5468/2015/07/P07006.’
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