Analog Quantum Bit Based on Pancharatnam-Berry Phase Metasurfaces

The emergence of information metamaterials has spurred significant advances in the field of information sciences. However, the current studies are predominantly focused on classical bits as the fundamental information units, and the classical bit can only be located at two poles of Bloch sphere, resulting in limited information capacity. To break such limit, quantum bits (qubits) offer a promising solution since they have superposition states anywhere on the Bloch sphere. Here, a Pancharatnam-Berry (PB) phase metasurface is used to emulate the qubits. Firstly, it proposes a theoretical concept of analog quantum bit and develops its mathematical and geometrical representations. Subsequently, a meta-atom is designed as a physical platform to implement the concept of analog qubits. By manipulating the geometric configuration of the proposed meta-atom, it achieves arbitrary superpositions of polarization states. A PB phase metasurface is experimentally fabricated to validate that the proposed analog qubit can be used to emulate the quantum bit in terms of both mathematical and geometrical representations. This work not only provides a theoretical foundation to go beyond the information limit of classical bits but also develops a feasible physics platform to investigate quantum information metasurfaces, which would complement and revolutionize classical information science. The emergence of information metamaterials has spurred significant advances in the field of information sciences. In this work, an analog quantum bit based on Pancharatnam-Berry phase metasurfaces is developed. It not only provides a theoretical foundation to go beyond the information limit of classical bits but also develops a feasible physics platform to investigate quantum information science.image