Optimal Estimation of Entangled States in Classical Quantum Simulator

Estimating the entanglement of qubits without measurement is a critical problem in quantum computing. Quantum algorithms using many qubits entail a substantial computational load as the quantum state increases exponentially. A mathematical tool like Schmidt's decomposition is virtually impossible to apply directly to such an algorithm. We propose a novel method for estimating entanglement states more precisely and quickly without measurement using a classical state vector quantum simulator. The fundamental principle of our idea is to project the state of the desired qubit from the entire quantum state into classical bits. Our concept can work independently of the exponential problem in classical quantum computers, ensuring faster-estimating entanglement relationships with fewer computing resources. In this paper, we present the verification results of our ideas using QPlayer, a special-purpose classical quantum simulator.