2011/04/07 by Yakov Kulik, O. P. Sushkov, Oleg P. Sushkov · 36 citations
Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Condensed matter physics #Critical point (mathematics) #Excitation #Ferromagnetism #Hydrostatic pressure #Magnetic field #Magnon #Mathematics #Mechanics #Phase transition #Physics #Physics of Superconductivity and Magnetism #Quantum #Quantum critical point #Quantum mechanics #Quantum phase transition #Quantum, superfluid, helium dynamics #Work (physics) #cond-mat.other #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.84.134418
published in Physical Review B 84(13) (American Physical Society) · 6 pages, 3 figures
arxiv created 2011/04/07 · openalex publication_date 2011/10/14 · arxiv updated 2015/03/18 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We consider a three-dimensional quantum antiferromagnet in the vicinity of a quantum critical point separating the magnetically ordered and the magnetically disordered phases. A specific example is TlCuCl3 where the quantum phase transition can be driven by hydrostatic pressure and/or by external magnetic field. As expected, two transverse and one longitudinal magnetic excitations have been observed in the pressure-driven magnetically ordered phase. According to the experimental data, the longitudinal magnon has a substantial width, which has not been understood and has remained a puzzle. In the present work, we explain the mechanism for the width, calculate the width and relate the value of the width with the parameters of the Bose condensate of magnons observed in the same compound. The method of an effective quantum field theory is employed in the work.