In quantum communication and quantum computing, the Bell state acts as an important role.For two qubit of discrete variable, Bell state is composted by two orthogonal to each other's physical state of a physical system.For the physical system consisting of continuous variables, a scheme is presented for generating the quasi-Bell-states of entangled squeezed states by using the Raman interaction of an Λ-type three-level atom with squeezed vacuum states (SVS) cavity fields.In this scheme, an atom initially prepared in its ground state is injected in proper order into several cavities initially prepared each in the SVS.After the atom interacting with these cavities, the entanglement of atom-cavity-field is generated.Afterwards, by measuring the atom we obtain the quasi-Bell-states of the entangled squeezed states.Also, the entanglement properties of bipartite entangled quasi-Bell-states as well as multipartite entangled SVSs are discussed.In quantum communication and quantum computing, the Bell state acts as an important role.For two qubit of discrete variable, Bell state is composted by two orthogonal to each other's physical state of a physical system.For the physical system consisting of continuous variables, a scheme is presented for generating the quasi-Bell-states of entangled squeezed states by using the Raman interaction of an Λ-type three-level atom with squeezed vacuum states (SVS) cavity fields.In this scheme, an atom initially prepared in its ground state is injected in proper order into several cavities initially prepared each in the SVS.After the atom interacting with these cavities, the entanglement of atom-cavity-field is generated.Afterwards, by measuring the atom we obtain the quasi-Bell-states of the entangled squeezed states.Also, the entanglement properties of bipartite entangled quasi-Bell-states as well as multipartite entangled SVSs are discussed.

International Symposium on Advances in Electrical, Electronics and Computer Engineering (ISAEECE)Jan 1, 20160 citations

Quantum Phase Estimation

Hiu Yung Wong

Springer eBooksJan 1, 20226 citations

Quantum-enhanced phase estimation with an amplified Bell state

Jaspreet Sahota, Daniel F. V. James

We propose a phase estimation protocol for optical interferometry that employs a probe state (containing on average $\overline{n}$ photons) obtained by squeezing each mode, separately, of a single photon path entangled Bell state. This scheme involves a Mach-Zehnder type interferometer for which each mode is squeezed after the first beam splitter. Information about the differential phase is extracted using a parity detection and the resulting measurement signal is super-resolving and supersensitive, with a minimum phase uncertainty $\ensuremath{\Delta}\ensuremath{\varphi}=2/(\overline{n}+1)$. This probe state can be generated with current technologies where $\overline{n}$ is in the order of many thousands of photons.We propose a phase estimation protocol for optical interferometry that employs a probe state (containing on average $\overline{n}$ photons) obtained by squeezing each mode, separately, of a single photon path entangled Bell state. This scheme involves a Mach-Zehnder type interferometer for which each mode is squeezed after the first beam splitter. Information about the differential phase is extracted using a parity detection and the resulting measurement signal is super-resolving and supersensitive, with a minimum phase uncertainty $\ensuremath{\Delta}\ensuremath{\varphi}=2/(\overline{n}+1)$. This probe state can be generated with current technologies where $\overline{n}$ is in the order of many thousands of photons.

arXiv:1310.0443Physical Review ADec 10, 201317 citations

Error Performance of Amplitude Shift Keying-Type Asymmetric Quantum Communication Systems

Tiancheng Wang, Tsuyoshi Sasaki Usuda

We propose an amplitude shift keying-type asymmetric quantum communication (AQC) system that uses an entangled state. As a first step toward development of this system, we evaluated and considered the communication performance of the proposed receiver when applied to the AQC system using a two-mode squeezed vacuum state (TSVS), the maximum quasi-Bell state, and the non-maximum quasi-Bell state, along with an asymmetric classical communication (ACC) system using the coherent state. Specifically, we derived an analytical expression for the error probability of the AQC system using the quasi-Bell state. Comparison of the error probabilities of the ACC system and the AQC systems when using the TSVS and the quasi-Bell state shows that the AQC system using the quasi-Bell state offers a clear performance advantage under specific conditions. Additionally, it was clarified that there are cases where the universal lower bound on the error probability for the AQC system was almost achieved when using the quasi-Bell state, unlike the case in which the TSVS was used.We propose an amplitude shift keying-type asymmetric quantum communication (AQC) system that uses an entangled state. As a first step toward development of this system, we evaluated and considered the communication performance of the proposed receiver when applied to the AQC system using a two-mode squeezed vacuum state (TSVS), the maximum quasi-Bell state, and the non-maximum quasi-Bell state, along with an asymmetric classical communication (ACC) system using the coherent state. Specifically, we derived an analytical expression for the error probability of the AQC system using the quasi-Bell state. Comparison of the error probabilities of the ACC system and the AQC systems when using the TSVS and the quasi-Bell state shows that the AQC system using the quasi-Bell state offers a clear performance advantage under specific conditions. Additionally, it was clarified that there are cases where the universal lower bound on the error probability for the AQC system was almost achieved when using the quasi-Bell state, unlike the case in which the TSVS was used.

EntropyMay 16, 20222 citations

Quantum Phase Estimation

Hiu Yung Wong

Springer eBooksJun 21, 20230 citations

We propose a phase estimation protocol for optical interferometry that employs a probe state (containing on average

\overline{n}

photons) obtained by squeezing each mode, separately, of a single photon path entangled Bell state. This scheme involves a Mach-Zehnder type interferometer for which each mode is squeezed after the first beam splitter. Information about the differential phase is extracted using a parity detection and the resulting measurement signal is super-resolving and supersensitive, with a minimum phase uncertainty $\ensuremath{\Delta}\ensuremath{\varphi}=2/(\overline{n}+1)$. This probe state can be generated with current technologies where

\overline{n}

is in the order of many thousands of photons.