update vbe in readme

Author: liwt31

README.md

@@ -93,4 +93,11 @@ If this project helps in your research, please cite our software whitepaper:
 
 [TenCirChem: An Efficient Quantum Computational Chemistry Package for the NISQ Era](https://arxiv.org/abs/2303.10825)
 
-which is also a good introduction to the software.
+which is also a good introduction to the software.
+
+## Research and Applications
+
+### Variational basis state encoder
+An efficient algorithm to encoder phonon states in electron-phonon systems for quantum computation.
+See [examples](https://github.com/tencent-quantum-lab/TenCirChem/tree/master/example).
+Reference paper: https://arxiv.org/pdf/2301.01442.pdf (published in PRR).

README_CN.md

@@ -90,4 +90,12 @@ TenCirChem 使用 Academic Public License 发布。
 
 [TenCirChem: An Efficient Quantum Computational Chemistry Package for the NISQ Era](https://arxiv.org/abs/2303.10825)
 
-这也是软件的一个很好的介绍。
+这也是软件的一个很好的介绍。
+
+## 研究和应用
+
+### 变分基矢编码器
+变分基矢编码器是编码电声子系统中的声子用以量子计算的高效算法。
+请参考[例子](https://github.com/tencent-quantum-lab/TenCirChem/tree/master/example).
+参考论文: https://arxiv.org/pdf/2301.01442.pdf (发表于PRR).
+

example/vbe_td.py

@@ -13,9 +13,8 @@
 from scipy.integrate import solve_ivp
 from opt_einsum import contract
 import tensorcircuit as tc
-from renormalizer import Op, Mpo, Model, OpSum
 
-from tencirchem import set_backend
+from tencirchem import set_backend, Op, Mpo, Model, OpSum
 from tencirchem.dynamic import get_ansatz, get_deriv, get_jacobian_func, qubit_encode_basis, sbm
 
 from vbe_lib import get_psi_indices, get_contracted_mpo, get_contract_args

example/vbe_ti.py

@@ -13,9 +13,8 @@
 import scipy
 from opt_einsum import contract
 import tensorcircuit as tc
-from renormalizer import Op, BasisSHO, BasisSimpleElectron, Mpo, Model
 
-from tencirchem import set_backend
+from tencirchem import set_backend, Op, BasisSHO, BasisSimpleElectron, Mpo, Model
 from tencirchem.dynamic import get_ansatz, qubit_encode_op, qubit_encode_basis
 from tencirchem.utils import scipy_opt_wrap
 

tencirchem/__init__.py

@@ -45,7 +45,9 @@
 
 # dynamic module
 # as an external interface
-from renormalizer import Op, BasisSHO, BasisHalfSpin, BasisSimpleElectron, BasisMultiElectron
+from renormalizer import Op, BasisSHO, BasisHalfSpin, BasisSimpleElectron, BasisMultiElectron, Model, Mpo
+from renormalizer.model import OpSum
+
 from tencirchem.utils.misc import get_dense_operator
 from tencirchem.dynamic.time_evolution import TimeEvolution
 

tencirchem/static/hea.py

@@ -554,8 +554,8 @@ def energy(self, params: Tensor = None, engine: str = None) -> float:
         >>> round(hea.energy([0, np.pi, 0, 0], "tensornetwork-noise"), 4)
         -1.1001
         >>> # HF state, measurement noise. Set the number of shots by `hea.shots`
-        >>> round(hea.energy([0, np.pi, 0, 0], "tensornetwork-shot"), 2)
-        -1.12
+        >>> round(hea.energy([0, np.pi, 0, 0], "tensornetwork-shot"), 1)
+        -1.1
         >>> # HF state, gate+measurement noise
         >>> hea.energy([0, np.pi, 0, 0], "tensornetwork-noise&shot")  # doctest:+ELLIPSIS
         -1...