We study a square-lattice instantaneous quantum polynomial-time (IQP) architecture subject to two-qubit gate-angle disorder and single-qubit dephasing using exact tensor-network simulations up to 576 qubits. Increasing disorder drives two consecutive crossovers toward classical simulability, with the output distribution first losing anticoncentration and then the tensor-network simulation cost dropping to polynomial as entanglement is suppressed.
Researchers find disorder drives quantum system to classical simulation at 576 qubits
We study a square-lattice instantaneous quantum polynomial-time (IQP) architecture subject to two-qubit gate-angle disorder and single-qubit dephasing using exact tensor-network simulations up to 576 qubits. Increasing disorder drives two consecutive crossovers toward classical simulability, with the output distribution first losing anticoncentration and then the tensor-network simulation cost dropping to polynomial as entanglement is suppressed.