Experimental realization of linear-optical partial SWAP gates

TL;DR

This paper demonstrates a linear-optical setup for implementing various two-qubit partial SWAP gates using polarization states of photons, with high performance validated through state reconstruction and entanglement measures.

Contribution

It introduces a versatile linear-optical method to realize partial SWAP gates with tunable operations and confirms their effectiveness through comprehensive quantum process characterization.

Findings

Successful implementation of partial SWAP gates with high fidelity.

Ability to switch between SWAP and entangling operations by adjusting a classical parameter.

High-quality entanglement generation demonstrated.

Abstract

We present a linear-optical implementation of a class of two-qubit partial SWAP gates for polarization states of photons. Different gate operations, including the SWAP and entangling square root of SWAP, can be obtained by changing a classical control parameter -- namely the path difference in the interferometer. Reconstruction of output states, full process tomography and evaluation of entanglement of formation prove very good performance of the gates.