scholarly journals Manipulation of eight-dimensional Bell-like states

2019 ◽  
Vol 5 (6) ◽  
pp. eaat9206 ◽  
Author(s):  
Ling-Jun Kong ◽  
Rui Liu ◽  
Wen-Rong Qi ◽  
Zhou-Xiang Wang ◽  
Shuang-Yin Huang ◽  
...  
Keyword(s):  
Information Technology ◽  
Angular Momentum ◽  
Quantum Information ◽  
Channel Capacity ◽  
High Dimensional ◽  
Projective Measurement ◽  
Optical Elements ◽  
The Third ◽  
Quantum Protocol ◽  
Linear Optical Elements

High-dimensional Bell-like states are necessary for increasing the channel capacity of the quantum protocol. However, their preparation and measurement are still huge challenges, especially for the latter. Here, we prepare an initial eight-dimensional Bell-like state based on hyperentanglement of spin and orbital angular momentum (OAM) of the first and the third orders. We design simple unitary operations to produce eight Bell-like states, which can be distinguished completely in theory among each other. We propose and illustrate a multiple projective measurement scheme composed of only linear optical elements and experimentally demonstrate that all the eight hyperentangled Bell-like states can be completely distinguished by our scheme. Our idea of manipulating the eight Bell-like states is beneficial to achieve the 3-bit channel capacity of quantum protocol, opening the door for extending applications of OAM states in future quantum information technology.

The analysis of high-capacity quantum secure direct communication using polarization and orbital angular momentum of photons

2019 ◽  
Vol 34 (02) ◽  
pp. 2050017 ◽  
Author(s):  
Lin-Yi Li ◽  
Tie-Jun Wang ◽  
Chuan Wang
Keyword(s):  
Angular Momentum ◽  
Quantum Information ◽  
Channel Capacity ◽  
Orbital Angular Momentum ◽  
Quantum Communication ◽  
High Capacity ◽  
Quantum Secure Direct Communication ◽  
Noise Elimination ◽  
Long Distance ◽  
Direct Communication

Higher channel capacity and noise elimination are the key requirements for the implementation of long-distance quantum communication. As the additional degrees of freedom (DoF) of photons can be employed to achieve higher channel capacity and security beyond the polarizations DoF of photons, the photonic qubits are always employed as the flying qubits in quantum communication and quantum information processing. Here, exploiting the multiple DoFs of photons, we present an efficient quantum secure direct communication protocol based on the coding and manipulation of qubits on both the polarization and the orbital angular momentum of photons. Also, the numerical simulation is studied to further clarify the improvement of the channel capacity and the security. It is found that the channel capacity and the error rate (caused by eavesdropping) of the QSDC protocol which encoded on the polarization DoF and the OAM DoF is significantly higher than that of coding on only polarization DoF. We believe this work could provide more evidence for the applications of higher-dimensional qubits in quantum information science.

scholarly journals Interface between path and orbital angular momentum entanglement for high-dimensional photonic quantum information

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Robert Fickler ◽  
Radek Lapkiewicz ◽  
Marcus Huber ◽  
Martin P.J. Lavery ◽  
Miles J. Padgett ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Quantum Information ◽  
Orbital Angular Momentum ◽  
High Dimensional

scholarly journals Efficient High-Dimensional Quantum Key Distribution with Hybrid Encoding

Entropy ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 80 ◽  
Author(s):  
Yonggi Jo ◽  
Hee Park ◽  
Seung-Woo Lee ◽  
Wonmin Son
Keyword(s):  
Angular Momentum ◽  
Quantum Key Distribution ◽  
Degrees Of Freedom ◽  
Single Photon ◽  
Key Distribution ◽  
Quantum States ◽  
High Dimensional ◽  
Practical Implementation ◽  
Secret Key ◽  
Optical Elements

We propose a schematic setup of quantum key distribution (QKD) with an improved secret key rate based on high-dimensional quantum states. Two degrees-of-freedom of a single photon, orbital angular momentum modes, and multi-path modes, are used to encode secret key information. Its practical implementation consists of optical elements that are within the reach of current technologies such as a multiport interferometer. We show that the proposed feasible protocol has improved the secret key rate with much sophistication compared to the previous 2-dimensional protocol known as the detector-device-independent QKD.

PENGARUH PEMANFAATAN TEKNOLOGI INFORMASI TERHADAP KEPUASAN END USER COMPUTING DENGAN KETIDAKPASTIAN TUGAS SEBAGAI VARIABEL MODERATING

2013 ◽  
Author(s):  
Herawati M
Keyword(s):  
Information Technology ◽  
Primary Data ◽  
End User ◽  
Moderating Variables ◽  
The Third ◽  
Use Of Technology ◽  
Task Uncertainty ◽  
Independent Variable ◽  
The City ◽  
End User Computing

This study aims to use information technology, uncertainty or moderation duties and interactions between task uncertainty with the use of information technology to end user computing satisfaction. In this study used 70 respondents who actively use computers and working with several companies banking on the city of Padang. The data used are the primary data obtained through questionnaires. The study used three types of variables, the first is the independent variable, namely the utilization of information technology, both moderating variables, namely the uncertainty of the task, the third is the dependent variable is satisfaction of end user computing. The stages of hypothesis testing is done by using a regression model of moderating and statistical t-test. Based on the results of testing the first hypothesis (HI) was found to significantly influence the utilization of information technology to the satisfaction of end user computing. The second hypothesis (H2) testing results found that task uncertainty did not significantly influence the end user computing satisfaction. The third hypothesis (H3) testing found that the interaction or moderation between the use of technology with task uncertainty no significant effect on end user computing satisfaction.

scholarly journals Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhe Zhao ◽  
Runzhou Zhang ◽  
Hao Song ◽  
Kai Pang ◽  
Ahmed Almaiman ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Atmospheric Turbulence ◽  
Channel Capacity ◽  
Orbital Angular Momentum ◽  
Beam Waist ◽  
Modal Coupling ◽  
Divergence Effect ◽  
Power Leakage ◽  
Calm Weather ◽  
Bad Weather

AbstractOrbital-angular-momentum (OAM) multiplexing has been utilized to increase the channel capacity in both millimeter-wave and optical domains. Terahertz (THz) wireless communication is attracting increasing attention due to its broadband spectral resources. Thus, it might be valuable to explore the system performance of THz OAM links to further increase the channel capacity. In this paper, we study through simulations the fundamental system-degrading effects when using multiple OAM beams in THz communications links under atmospheric turbulence. We simulate and analyze the effects of divergence, turbulence, limited-size aperture, and misalignment on the signal power and crosstalk of THz OAM links. We find through simulations that the system-degrading effects are different in two scenarios with atmosphere turbulence: (a) when we consider the same strength of phasefront distortion, faster divergence (i.e., lower frequency; smaller beam waist) leads to higher power leakage from the transmitted mode to neighbouring modes; and (b) however, when we consider the same atmospheric turbulence, the divergence effect tends to affect the power leakage much less, and the power leakage increases as the frequency, beam waist, or OAM order increases. Simulation results show that: (i) the crosstalk to the neighbouring mode remains < − 15 dB for a 1-km link under calm weather, when we transmit OAM + 4 at 0.5 THz with a beam waist of 1 m; (ii) for the 3-OAM-multiplexed THz links, the signal-to-interference ratio (SIR) increases by ~ 5–7 dB if the mode spacing increases by 1, and SIR decreases with the multiplexed mode number; and (iii) limited aperture size and misalignment lead to power leakage to other modes under calm weather, while it tends to be unobtrusive under bad weather.

scholarly journals Quantum information technology

2003 ◽  
Vol 6 (1) ◽  
pp. 30-36 ◽  
Author(s):  
Timothy P Spiller
Keyword(s):  
Information Technology ◽  
Quantum Information

scholarly journals Realising high-dimensional quantum entanglement with orbital angular momentum

2015 ◽  
Vol 111 (1/2) ◽  
pp. 1-9 ◽  
Author(s):  
Melanie G. McLaren ◽  
Filippus S. Roux ◽  
Andrew Forbes
Keyword(s):  
Angular Momentum ◽  
Quantum Entanglement ◽  
Orbital Angular Momentum ◽  
High Dimensional

scholarly journals Arbitrary polarization conversion for pure vortex generation with a single metasurface

Nanophotonics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 727-732
Author(s):  
Marco Piccardo ◽  
Antonio Ambrosio
Keyword(s):  
Angular Momentum ◽  
Polarization Conversion ◽  
Vortex Beam ◽  
Vortex Generation ◽  
Optical Elements ◽  
Amplitude Control ◽  
Cavity Resonators ◽  
Vortex Beams ◽  
Topological Charges ◽  
Selection Of

AbstractThe purity of an optical vortex beam depends on the spread of its energy among different azimuthal and radial modes, also known as $\ell $- and p-modes. The smaller the spread, the higher the vortex purity and more efficient its creation and detection. There are several methods to generate vortex beams with well-defined orbital angular momentum, but only few exist allowing selection of a pure radial mode. These typically consist of many optical elements with rather complex arrangements, including active cavity resonators. Here, we show that it is possible to generate pure vortex beams using a single metasurface plate—called p-plate as it controls radial modes—in combination with a polarizer. We generalize an existing theory of independent phase and amplitude control with birefringent nanopillars considering arbitrary input polarization states. The high purity, sizeable creation efficiency, and impassable compactness make the presented approach a powerful complex amplitude modulation tool for pure vortex generation, even in the case of large topological charges.

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