Gaussian private quantum channel with squeezed coherent states

Area of Science:

• Quantum Information Science
• Quantum Communication Security

Background:

• Conventional quantum key distribution (QKD) focuses on secure classical bit sharing.
• Private quantum channels (PQC) aim for secure transmission of quantum states using a one-time pad.
• Gaussian private quantum channels (GPQC) operate within the continuous variable regime.

Purpose of the Study:

• To propose and analyze a novel Gaussian private quantum channel enhanced with squeezed coherent states (GPQCwSC).
• To generalize existing GPQC protocols that utilize only coherent states (GPQCo).
• To evaluate the performance improvement of GPQCwSC over GPQCo in terms of accessible information.

Main Methods:

• Theoretical framework for GPQC enhanced with squeezed coherent states.
• Mathematical analysis comparing accessible information bounds between GPQCwSC and GPQCo.
• Investigation of squeezed states' advantage against beam splitting attacks in continuous variable QKD.
• Approximation of squeezing operations as superpositions of displacement operations.

Main Results:

• GPQCwSC demonstrates a superior upper bound on accessible information compared to GPQCo.
• Squeezed states offer enhanced security against beam splitting attacks in continuous variable QKD.
• Squeezing operations can be effectively approximated by displacement operations under small squeezing conditions.

Conclusions:

• The proposed GPQCwSC offers significant advantages for secure quantum communication.
• Squeezed coherent states represent a promising advancement for enhancing the security and capacity of private quantum channels.
• The findings contribute to the development of more robust and efficient quantum communication protocols.