Entanglement-enhanced quantum rectification

Coherent quantum dynamics is the powerful driver behind quantum technology which exploits entanglement and interference. Combining these with the statistical behavior of thermal baths yields entirely new possibilities that can be exploited in quantum devices. An example of such a device can be made by coupling two segments of a quantum spin chain through a two-way junction that allows for entanglement of spins at the interface. External thermal baths at both ends can be used to drive the interface into a coherent entanglement. With one cold and one hot bath, a net number of spins will travel between them generating a spin current. For properly chosen system parameters, the entangled state developed at the interface will block any spins from traveling past through destructive interference. However, the superposition only develops for one configuration of the two baths blocking spin transport one way while letting a current flow in the other. This exact feature makes for a perfect diode working through purely quantum effects and driven by the non-unitarity of the bath dynamics. Additionally, the entanglement can be dramatically changed through external tuning which may be used for metrology.