Delta-Function Bose Gas Picture of S=1 Antiferromagnetic Quantum Spin Chains Near Critical Fields
| dc.creator | Okunishi, Kouichi | |
| dc.creator | Hieida, Yasuhiro | |
| dc.creator | Akutsu, Yasuhiro | |
| dc.date | 1998-07-18 | |
| dc.date.accessioned | 2026-07-07T06:34:02Z | |
| dc.date.available | 2026-07-07T06:34:02Z | |
| dc.description | We study the zero-temperature magnetization curve (M-H curve) of the S=1 bilinear-biquadratic spin chain, whose Hamiltonian is given by $H=\sum_{i} S_i S_{i+1}+β(S_iS_{i+1})^2 with $0 \leq β<1$. We focus on validity of the delta-function bose-gas picture near the two critical fields: the saturation field $H_s$ and the lower critical field $H_c$ associated with the Haldane gap. Near $H_s$, we take ``low-energy effective S-matrix'' approach, which gives correct effective bose-gas coupling constant $c$, different from the spin-wave value. Comparing the M-H curve of the bose gas with the product-wavefunction renormalization group (PWFRG) calculation, excellent agreement is seen. Near $H_c$, comparing the PWFRG result with the bose-gas prediction, we find that there are two distinct regions of $β$ separated by a critical value $β_c(\approx 0.41)$. In the region $0<β<β_c$, the effective coupling $c$ is positive but rather small. The small value of $c$ makes the ``critical region'' of the square-root behavior $M\sim \sqrt{H-H_c}$ very narrow. Further, we find that in the $β\to β_c-0$, the square-root behavior transmutes to a different one, $M\sim (H-H_c)^{1/4}$. In the region $β_c<β<1$, the square-root behavior is rather distinct, but the effective coupling $c$ becomes negative. | |
| dc.description | 6 pages, RevTeX, 8 ps figures | |
| dc.identifier | https://arxiv.org/abs/cond-mat/9807266 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/9807266 | |
| dc.identifier | Phys. RevB. 59 6806 (1999) | |
| dc.identifier | doi:10.1103/PhysRevB.59.6806 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/99395 | |
| dc.subject | Statistical Mechanics | |
| dc.title | Delta-Function Bose Gas Picture of S=1 Antiferromagnetic Quantum Spin Chains Near Critical Fields | |
| dc.type | text |