Continuous-Variable Entanglement Test in Driven Quantum Contacts

Area of Science:

• Quantum physics
• Condensed matter physics
• Quantum information science

Background:

• Standard entanglement tests like the Clauser-Horne-Shimony-Holt inequality fail in mesoscopic junctions at finite temperatures due to bidirectional particle flow.
• This failure is expected in ac-driven contacts where electrons and holes are generated.
• A new method is needed to test entanglement in such systems.

Purpose of the Study:

• To develop a continuous-variable entanglement test applicable to electrons and holes generated by an ac drive.
• To investigate the conditions under which entanglement can be detected in ac-driven mesoscopic junctions.

Main Methods:

• Development of a continuous-variable entanglement test.
• Application of the test to ac-driven electron-hole pair creation in mesoscopic junctions.
• Analysis of generalized Bell inequality violations based on junction properties and ac voltage parameters.

Main Results:

• The generalized Bell inequality is violated at low temperatures in junctions with low conductance or few transport channels.
• Violation occurs when ac voltages create a small number of electron-hole pairs per cycle.
• The entanglement test's sensitivity depends on the total number of electron-hole pairs and their creation probability distribution, analogous to the Fano factor.

Conclusions:

• A novel continuous-variable entanglement test is suitable for ac-driven electron-hole pairs.
• Entanglement detection is feasible in mesoscopic junctions under specific low-temperature and low-excitation conditions.
• The developed test provides a new tool for exploring quantum phenomena in driven quantum systems.