Quantum teleportation of multiple degrees of freedom of a single photon

Xi-Lin Wang,    Xin-Dong Cai,    Zu-En Su,    Ming-Cheng Chen,    Dian Wu,    Li Li,    Nai-Le Liu,    Chao-Yang Lu    & Jian-Wei Pan

Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
Xi-Lin Wang, Xin-Dong Cai, Zu-En Su, Ming-Cheng Chen, Dian Wu, Li Li, Nai-Le Liu, Chao-Yang Lu & Jian-Wei Pan
CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
Xi-Lin Wang, Xin-Dong Cai, Zu-En Su, Ming-Cheng Chen, Dian Wu, Li Li, Nai-Le Liu, Chao-Yang Lu & Jian-Wei Pan
Contributions
C.-Y.L. and J.-W.P. had the idea for and designed the research; X.-L.W., X.-D.C., Z.-E.S., M.-C.C., D.W., L.L., N.-L.L. and C.-Y.L. performed the experiment; X.-L.W., M.-C.C., C.-Y.L. and J.-W.P. analysed the data; C.-Y.L. and J.-W.P. wrote the paper with input from all authors; and N.-L.L., C.-Y.L. and J.-W.P. supervised the whole project.

Competing financial interests
The authors declare no competing financial interests.

Corresponding authors
Correspondence to: Chao-Yang Lu or Jian-Wei Pan

Quantum teleportation1 provides a ‘disembodied’ way to transfer quantum states from one object to another at a distant location, assisted by previously shared entangled states and a classical communication channel. As well as being of fundamental interest, teleportation has been recognized as an important element in long-distance quantum communication2, distributed quantum networks3 and measurement-based quantum computation4, 5. There have been numerous demonstrations of teleportation in different physical systems such as photons6, 7, 8, atoms9, ions10, 11, electrons12 and superconducting circuits13. All the previous experiments were limited to the teleportation of one degree of freedom only. However, a single quantum particle can naturally possess various degrees of freedom—internal and external—and with coherent coupling among them. A fundamental open challenge is to teleport multiple degrees of freedom simultaneously, which is necessary to describe a quantum particle fully and, therefore, to teleport it intact. Here we demonstrate quantum teleportation of the composite quantum states of a single photon encoded in both spin and orbital angular momentum. We use photon pairs entangled in both degrees of freedom (that is, hyper-entangled) as the quantum channel for teleportation, and develop a method to project and discriminate hyper-entangled Bell states by exploiting probabilistic quantum non-demolition measurement, which can be extended to more degrees of freedom. We verify the teleportation for both spin–orbit product states and hybrid entangled states, and achieve a teleportation fidelity ranging from 0.57 to 0.68, above the classical limit. Our work is a step towards the teleportation of more complex quantum systems, and demonstrates an increase in our technical control of scalable quantum technologies.