TenCirChem is an efficient and versatile quantum computation package for molecular properties. TenCirChem is based on TensorCircuit, with heavy optimization for chemistry applications.

The package is written in pure Python and can be obtained via pip as:

pip install tencirchem

UCCSD calculation example

from tencirchem import UCCSD, M

d = 0.8
# distance unit is angstrom
h4 = M(atom=[["H", 0, 0, d * i] for i in range(4)])

# setup
uccsd = UCCSD(h4)
# calculate
uccsd.kernel()
# analyze result
uccsd.print_summary(include_circuit=True)

Running uccsd.kernel() in the above code determines the optimized circuit ansatz parameters and VQE energy.
It is equally straightforward for the user to supply their own custom parameters:

import numpy as np

from tencirchem import UCCSD
from tencirchem.molecule import h4

uccsd = UCCSD(h4)
# evaluate various properties based on custom parameters
params = np.zeros(uccsd.n_params)
print(uccsd.statevector(params))
print(uccsd.energy(params))
print(uccsd.energy_and_grad(params))

Please refer to the documentation for more examples and customization.

• Statics module
  • Extremely fast UCC calculation with UCCSD, kUpCCGSD, pUCCD
  • Noisy circuit simulation via TensorCircuit
  • Custom integrals, active space approximation, RDMs, GPU support, etc.
• Dynamics module
  • Transformation from renormalizer models to qubit representation
  • VQA algorithm based on JAX
  • Built-in models: spin-boson model, pyrazine S1/S2 internal conversion dynamics

• Fast
  • UCC speed 10000x faster than other packages
    • Example: H8 with 16 qubits in 2s (CPU). H10 with 20 qubits in 14s (GPU)
    • Achieved by analytical expansion of UCC factors and exploitation of symmetry
• Easy to hack
  • Avoid defining new classes and wrappers when possible
    • Example: Excitation operators are represented as tuple of int. An operator pool is simply a list of tuple
  • Minimal class inheritance hierarchy: at most two levels
  • Expose internal variables through class attributes

TenCirChem is released under Academic Public License. See the LICENSE file for details. In short, you can use TenCirChem freely for non-commercial/academic purpose and commercial use requires a commercial license.