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qrate is a Python package designed to provide a simple and efficient solver for quantum transport using the rate equation. It is specially useful for simulating quantum transport phenomena in mesoscopic systems, such as quantum dots and nanostructures defined by second quantized Hamiltonians. We use sympy.physics.quantum.FermionOp to define the Hamiltonian and solve the rate equations.

NOTE: This package is currently under development and the interface is being reworked. The API may change in future releases.

Basic Usage

from qrate import solvers

# Define your system
def hamiltonian(t=1.0):
    return np.array([[0, t], [t, 0]])

def lead_coupling(gamma=0.1):
    return np.array([[gamma, 0], [0, 0]])

# Create conductance function
current_fn = solvers.current_solver(
    f_hamiltonian=hamiltonian,
    f_leads=[lead_coupling, lead_coupling],
    system_parameters={'t': 1.0},
    lead_parameters={'gamma': 0.1}
)

# Compute conductance for given bias
bias = np.array([0.0, 0.1])
current = current_fn(bias)

Getting Started

Install via pip:

pip install git+https://gitlab.kwant-project.org/qt/qrate.git

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For more information, visit the project repository.