Quantum teleportation via photonic Faraday rotation Juan-Juan Chen ( 陈娟娟 ) Advisor: Jun-Hong An

3 Summary 3 Acknowledgments 4 Quantum teleportation via Faraday rotation 1 2 Introduction

 Cavity QED system gives an ideal candidate for QIP. Stationary atoms = static qubits for storing QI; Photons = Flying qubits for transmitting QI. Cavity QED system is perfect interface for the interaction atoms and photons.

 The earlier QT schemes use atoms to transfer QI. Not suitable for long-distance QT. Not easy to keep the QI in the flying atoms. The high-Q condition for the cavities is hard to meet. QT in cavity QED system

 Some schemes use the leaking photons as flying qubits to QT. Advantage: Works in low-Q condition. Disadvantage: Intrinsically probabilistic.

Low-Q cavity Is QT with the photon as flying qubit realizable in this low-Q cavity regime in a deterministic fashion? Condition:. Although the imperfection of the cavity mirror induces the damping of the cavity field, it gives us an efficient injection way of the photon to the cavity.

The Faraday rotation of the J - C model From J.-H. An et al. (2009). Faraday rotation

Figure 3.1: Schematic for teleporting an unknown atomic state from Alice's side to the atoms at Bob's side. The entanglement channel is formed between Bob's atom and the flying photon. The arrows shows the flying direction of the photon, and the bold line denotes a quarter-wave plate. The schematic of our scheme

 The scalability of our scheme. The case of bipartite state The case of tripartite state

Advantages to our schemes : Photons as flying qubits to transmit QI; suitable for long-distance QT. Work in low-Q regime of cavities; the damping of cavity plays active role; Insensitive to atomic spontaneous emission; Only need two-qubit entanglement in multi-qubit QT; Intrinsically deterministic.

Acknowledgments I am firstly greatly indebted to my advisor, Professor Jun-Hong An for his serious patience, careful guidance and assistance to my research work during these three years. At same time I would also like to thank Professor Hong-Gang Luo and collegues of the Center for Interdisciplinary Studies for many valuable and helpful discussions with me. In the last, I can not forget the long-term supports of my parents, mysister to my study.