Promoting quantum correlations in deterministic quantum computation with a one-qubit model via postselection

Autor: E. I. Goettems, E. I. Duzzioni, Thiago O. Maciel, Diogo O. Soares-Pinto
Rok vydání: 2021
Předmět:
Zdroj: Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual)
Universidade de São Paulo (USP)
instacron:USP
ISSN: 2469-9934
2469-9926
DOI: 10.1103/physreva.103.042416
Popis: The deterministic quantum computation with one qubit (DQC1) model is a restricted model of quantum computing able to calculate efficiently the normalized trace of a unitary matrix. In this work, we analyze the quantum correlations called entanglement, Bell's nonlocality, quantum discord, and coherence generated by the DQC1 circuit considering only two qubits (auxiliary and control). For the standard DQC1 model, only quantum discord and coherence appear. By introducing a filter in the circuit we purify the auxiliary qubit, taking it out from the totally mixed state and consequently promoting other quantum correlations between the qubits, such as entanglement and Bell's nonlocality. Through the optimization of the purification process, we conclude that even a small purification is enough to generate entanglement and Bell's nonlocality. We obtain, that by applying the purification process repeatedly an average of 12 times, the auxiliary qubit becomes $99%$ pure. In this situation, almost maximally entangled states are achieved, which almost maximally violate Bell's inequality. This result suggests that with a simple modification, the DQC1 model can be promoted to a universal model of quantum computing.
Databáze: OpenAIRE