Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
Physical implementation of non-physical quantum operations: realization of the universal transpose operation
Hyang‐Tag Lim, Young-Sik Ra, Yong‐Su Kim, Joonwoo Bae, Yoon-Ho Kim
Abstract
The universal transpose of quantum states is an anti-unitary transformation that is not allowed in quantum theory. In this work, we investigate approximating the universal transpose of quantum states of two-level systems (qubits) using the method known as structural physical approximation. We also report its experimental implementation in linear optics. The scheme is optimal in that the maximal fidelity is attained, and also practical as measurement and preparation of quantum states that are experimentally feasible within current technologies are solely applied.