Bose-Einstein condensation and entanglement in magnetic systems

Abstract

We present a study of magnetic field induced quantum phase transitions in insulating systems. A generalized scaling theory is used to obtain the temperature dependence of several physical quantities along the quantum critical trajectory ($H=H_C$, $T\to 0$) where $H$ is a longitudinal external magnetic field and $H_C$ the critical value at which the transition occurs. We consider transitions from a spin liquid at a critical field $H_{C1}$ and from a fully polarized paramagnet, at $H_{C2}$, into phases with long range order in the transverse components. The transitions at $H_{C1}$ and $H_{C2}$ can be viewed as Bose-Einstein condensations of magnons which however belong to different universality classes since they have different values of the dynamic critical exponent $z$. Finally, we use that the magnetic susceptibility is an entanglement witness to discuss how this type of correlation sets in as the system approaches the quantum critical point along the critical trajectory, $H=H_{C2}$, $T\to 0$.

7 pages, 1 Table; accepted version; changes in text and new references

References in corpus (4)

• Diverging Entanglement Length in Gapped Quantum Spin Systems
• Dimensional reduction at a quantum critical point
• Bose-Einstein Condensation of Magnons in Cs2CuCl4
• Entanglement and factorized ground states in two-dimensional quantum antiferromagnets

Cited by in corpus (3)

• Thermal entanglement of one-dimensional Heisenberg quantum spin chains in magnetic fields
• Bose-Einstein condensation in antiferromagnets close to the saturation field
• Interplay of quantum and classical fluctuations near quantum critical points