Enhanced discrimination of high-dimensional quantum states by concatenated optimal measurement strategies
Carregando...
Data
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Minas Gerais
Descrição
Tipo
Artigo de periódico
Título alternativo
Primeiro orientador
Membros da banca
Resumo
The impossibility of deterministic and error-free discrimination among nonorthogonal quantum
states lies at the core of quantum theory and constitutes a primitive for secure quantum
communication. Demanding determinism leads to errors, while demanding certainty leads to
some inconclusiveness. One of the most fundamental strategies developed for this task is the
optimal unambiguous measurement. It encompasses conclusive results, which allow for error-free
state retrodictions with the maximum success probability, and inconclusive results, which are
discarded for not allowing perfect identifications. Interestingly, in high-dimensional Hilbert spaces
the inconclusive results may contain valuable information about the input states. Here, we
theoretically describe and experimentally demonstrate the discrimination of nonorthogonal states
from both conclusive and inconclusive results in the optimal unambiguous strategy, by
concatenating a minimum-error measurement at its inconclusive space. Our implementation
comprises four- and nine-dimensional spatially encoded photonic states. By accessing the
inconclusive space to retrieve the information that is wasted in the conventional protocol, we
achieve significant increases of up to a factor of 2.07 and 3.73, respectively, in the overall
probabilities of correct retrodictions. The concept of concatenated optimal measurements
demonstrated here can be extended to other strategies and will enable one to explore the full
potential of high-dimensional nonorthogonal states for quantum communication with larger
alphabets.
Abstract
Assunto
Comunicação quântica
Palavras-chave
Quantum communication, Quantum state discrimination, Optimal unambiguous measurement, Minimum error measurement, Concatenated measurement strategies
Citação
Departamento
Curso
Endereço externo
https://iopscience.iop.org/article/10.1088/2058-9565/ac37c4