Generation of bipartite mechanical cat state by performing projective Bell state measurement

TL;DR

This paper demonstrates the generation of bipartite mechanical Schrödinger cat states via entanglement swapping and projective Bell state measurements, enabling tests of quantum nonlocality in macroscopic systems.

Contribution

It introduces a novel method to create bipartite phononic Bell cat states using superconducting qubits and Bell state measurements, advancing quantum network capabilities.

Findings

Successful generation of four bipartite phononic Bell cat states

Performed Bell inequality tests confirming quantum nonlocality

Potential applications in quantum network processors

Abstract

Quantum state preparation and measurement of photonic and phononic Schr\"odinger cat states have gathered significant interest due to their implications for alternative encoding schemes in quantum computation. These scheme employ coherent state superpositions, leveraging the expanded Hilbert space provided by cavity or mechanical resonators in contrast to two-level systems. Moreover, such cat states also serve as a platform for testing fundamental quantum phenomena in macroscopic systems. In this study, we generate four bipartite phononic Bell cat states using an entanglement swapping scheme achieved through projective Bell state measurements on two superconducting qubits. Subsequently, we conduct a Bell inequality test on the bipartite cat state using the CHSH formulation. Given that the entangled cat states are generated through entanglement swapping, our approach could hold promising applications for the advancement of complex quantum network processors based on continuous variable systems.