Finite-time quantum entanglement in propagating squeezed microwaves.

Area of Science:

• Quantum optics
• Quantum information science
• Microwave quantum devices

Background:

• Two-mode squeezing (TMS) is a quantum entanglement phenomenon showing cross-correlations between subsystems.
• TMS states are valuable resources for quantum communication, despite individual subsystems lacking quantum signatures.
• Propagating microwave states are crucial for practical quantum communication applications.

Purpose of the Study:

• To generate propagating microwave two-mode squeezed states.
• To experimentally investigate the dephasing of quantum cross-correlations in continuous-variable microwave TMS states.
• To develop a theory model for dephasing and predict performance for quantum communication protocols.

Main Methods:

• Generation of propagating microwave TMS states using a beam splitter and Josephson parametric amplifiers.
• Experimental study of dephasing processes affecting quantum cross-correlations.
• Theoretical modeling of dephasing and prediction of fidelities for quantum communication protocols.

Main Results:

• Successful generation of propagating microwave TMS states.
• Accurate description of the fundamental dephasing process in these states.
• Insights into finite-time entanglement limits for continuous-variable microwave states.

Conclusions:

• The study provides a comprehensive understanding of dephasing in microwave TMS states.
• The findings predict high fidelities for quantum communication protocols like remote state preparation and quantum teleportation.
• This work advances the development of quantum communication technologies using microwave quantum states.