不同版本低温热容计算结果疑问

[momotrees]

老师您好，我分别使用v2.3和v3.0两个版本，使用相同参数计算，发现v2.3版本在接近0K时热容接近0，v3.0版本在接近0K时热容接近1。按照固体物理，低温时热容应该接近0，请问是什么原因造成高版本的计算结果与0有偏差呢？

以下部分是v2.3版本的计算参数。v3.0的计算参数与之完全相同，包括nthermal，nsweep，tau等
This is mcsolver's save file, version: 2.3
Lattice:
1.000000000 0.000000000 0.000000000
0.000000000 1.000000000 0.000000000
0.000000000 0.000000000 1.000000000
Supercell used in MC simulations:
16 16 1
Orbitals in cell:
2
Positions, initial spin states and onsite-anisotropy of every orbital:
orb 0: type 0 spin 1.000000000 pos [0.000000000 0.000000000 0.000000000] Dx 0.000000000 Dy 0.000000000 Dz 4.635500000 h 0.000000000
orb 1: type 0 spin 1.000000000 pos [0.555555556 0.555555556 0.000000000] Dx 0.000000000 Dy 0.000000000 Dz 4.635500000 h 0.000000000
Bonds:
8
id, source, target, overLat, exchange matrix elements of each bond:
bond 0: Jx -824.389630000 Jy -824.389630000 Jz -824.389630000 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 1 over [0 0 0]
bond 1: Jx -824.389630000 Jy -824.389630000 Jz -824.389630000 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 1 over [-1 0 0]
bond 2: Jx -824.389630000 Jy -824.389630000 Jz -824.389630000 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 1 over [0 -1 0]
bond 3: Jx -824.389630000 Jy -824.389630000 Jz -824.389630000 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 1 over [-1 -1 0]
bond 4: Jx -455.199943000 Jy -455.199943000 Jz -455.199943000 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 0 over [1 0 0]
bond 5: Jx -455.199943000 Jy -455.199943000 Jz -455.199943000 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 0 over [0 1 0]
bond 6: Jx -455.199943000 Jy -455.199943000 Jz -455.199943000 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 1 to orb 1 over [1 0 0]
bond 7: Jx -455.199943000 Jy -455.199943000 Jz -455.199943000 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 1 to orb 1 over [0 1 0]
Temperature scanning region:
Tmin 2.000000000 Tmax 10.000000000 nT 5
Field scanning region:
Hmin 0.000000000 Hmax 0.100000000 nH 1
Dipole long-range coupling:
alpha 0.000000
Measurement:
measure the correlation function between orb0 and orb0 over [0 0 0]
Supergroup
OrbGroup:1
Supergroup
group0 orb0-orb0
Distribution output frame: 0
Sweeps for thermalization and statistics, and relaxiation step for each sweep:
120000 1200000 0
XAxis type:
T
Model type:
Heisenberg
Algorithm:
Metropolis
Ncores:
8

[golddoushi]

低温的计算数据没有意义，蒙特卡洛算法不适合做低温