Quantum tricriticality in transverse Ising-like systems

M.T. Mercaldo; I. Rabuffo; A. Naddeo; A. Caramico D’Auria; L. De Cesare

doi:10.1140/epjb/e2011-20621-0

2022 Impact factor 1.6

Condensed Matter and Complex Systems

Eur. Phys. J. B 84, 371-379 (2011)
https://doi.org/10.1140/epjb/e2011-20621-0

Regular Article

Quantum tricriticality in transverse Ising-like systems

M.T. Mercaldo¹^,2^a, I. Rabuffo¹^,2, A. Naddeo¹^,2, A. Caramico D’Auria³ and L. De Cesare¹^,2

¹ Dipartimento di Fisica “E. R. Caianiello”, Università di Salerno, 84084 Fisciano ( Salerno), Italy
² CNISM, Unità di Salerno, 84084 Fisciano ( Salerno), Italy
³ Dipartimento di Scienze Fisiche, Università di Napoli Federico II, 80125 Napoli, Italy

^a e-mail: mtm@physics.unisa.it

Received: 27 July 2011
Received in final form: 4 October 2011
Published online: 23 November 2011

Abstract

The quantum tricriticality of d-dimensional transverse Ising-like systems is studied by means of a perturbative renormalization group approach focusing on static susceptibility. This allows us to obtain the phase diagram for 3 ≤ d < 4, with a clear location of the critical lines ending in the conventional quantum critical points and in the quantum tricritical one, and of the tricritical line for temperature T ≥ 0. We determine also the critical and the tricritical shift exponents close to the corresponding ground state instabilities. Remarkably, we find a tricritical shift exponent identical to that found in the conventional quantum criticality and, by approaching the quantum tricritical point increasing the non-thermal control parameter r, a crossover of the quantum critical shift exponents from the conventional value φ = 1/(d − 1) to the new one φ = 1/2(d − 1). Besides, the projection in the (r,T)-plane of the phase boundary ending in the quantum tricritical point and crossovers in the quantum tricritical region appear quite similar to those found close to an usual quantum critical point. Another feature of experimental interest is that the amplitude of the Wilsonian classical critical region around this peculiar critical line is sensibly smaller than that expected in the quantum critical scenario. This suggests that the quantum tricriticality is essentially governed by mean-field critical exponents, renormalized by the shift exponent φ = 1/2(d − 1) in the quantum tricritical region.