Experimental Long-Distance Decoy-State Quantum Key Distribution Based on Polarization Encoding

Peng, Cheng-Zhi; Zhang, Jun; Yang, Dong; Gao, Weibo; Ma, Huai-Xin; Yin, Hao; Zeng, Heping; Yang, Tao; Wang, Xiang-Bin; Pan, Jian-Wei

doi:10.1103/physrevlett.98.010505

Cited by 335 publications

(157 citation statements)

References 35 publications

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“…Second, different from a continuous-variable system, its teleportation fidelity is insensitive to photon losses. In practice, an overall transmission attenuation of 10 −4 is tolerable with current technology, as demonstrated in recent experiments 21,22 . Moreover, as the collective state of atomic ensembles is used to encode an atomic qubit, the teleported state can be easily read out in a controllable time for further quantum information applications.…”

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confidence: 98%

Memory-built-in quantum teleportation with photonic and atomic qubits

et al. 2008

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The combination of quantum teleportation 1 and quantum memory 2-5 of photonic qubits is essential for future implementations of large-scale quantum communication 6 and measurement-based quantum computation 7,8 . Both steps have been achieved separately in many proof-of-principle experiments 9-14 , but the demonstration of memory-built-in teleportation of photonic qubits remains an experimental challenge. Here, we demonstrate teleportation between photonic (flying) and atomic (stationary) qubits. In our experiment, an unknown polarization state of a single photon is teleported over 7 m onto a remote atomic qubit that also serves as a quantum memory. The teleported state can be stored and successfully read out for up to 8 µs. Besides being of fundamental interest, teleportation between photonic and atomic qubits with the direct inclusion of a readable quantum memory represents a step towards an efficient and scalable quantum network 2-8 .Quantum teleportation 1 , a way to transfer the state of a quantum system from one place to another, was first demonstrated between two independent photonic qubits 9 ; later developments include demonstration of entanglement swapping 10 , open-destination teleportation 11 and teleportation between two ionic qubits 15,16 . Teleportation has also been demonstrated for a continuous-variable system, that is, transferring a quantum state from one light beam to another 17 and, more recently, even from light to matter 18 . However, the above demonstrations have several drawbacks, especially in long-distance quantum communication. On the one hand, the absence of quantum storage makes the teleportation of light alone non-scalable. On the other hand, in teleportation of ionic qubits, the shared entangled pairs were created locally, which limits the teleportation distance to a few micrometres and is difficult to extend to large distances. In continuous-variable teleportation between light and matter, the experimental fidelity is extremely sensitive to the transmission loss-even in the ideal case, only a maximal attenuation of 10 −1 is tolerable 19 . Moreover, the complicated protocol required for retrieving the teleported state in the matter 20 is beyond the reach of current technology.The combination of quantum teleportation and quantum memory of photonic qubits 2-5 could provide a novel way to overcome these drawbacks. Here, we achieve this appealing combination by experimentally implementing teleportation between discrete photonic (flying) and atomic (stationary) qubits.In our experiment, we use the polarized photonic qubits as the information carriers and the collective atomic qubits [2][3][4][5]12 (an effective qubit consists of two atomic ensembles, each with 10 6 rubidium-87 atoms) as the quantum memory. In memorybuilt-in teleportation, an unknown polarization state of single photons is teleported onto and stored in a remote atomic qubit via a Bell-state measurement between the photon to be teleported and the photon that is originally entangled with the atomic qubit. The protocol has ...

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confidence: 98%

Memory-built-in quantum teleportation with photonic and atomic qubits

et al. 2008

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“…Afterwards, some practical decoy-state protocols are proposed [25,26,27,28]. The experimental demonstrations for decoy state method have been done recently [29,30,31,32,33,34]. Other than decoy state method, there are other approaches to enhance the performance of the coherent state QKD, such as QKD with strong reference pulses [35,36] and differential-phase-shift QKD [37].…”

Section: Introductionmentioning

confidence: 99%

Quantum key distribution with entangled photon sources

2007

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A parametric down-conversion (PDC) source can be used as either a triggered single photon source or an entangled photon source in quantum key distribution (QKD). The triggering PDC QKD has already been studied in the literature. On the other hand, a model and a post-processing protocol for the entanglement PDC QKD are still missing. In this paper, we fill in this important gap by proposing such a model and a post-processing protocol for the entanglement PDC QKD.Although the PDC model is proposed to study the entanglement-based QKD, we emphasize that our generic model may also be useful for other non-QKD experiments involving a PDC source.Since an entangled PDC source is a basis independent source, we apply Koashi-Preskill's security analysis to the entanglement PDC QKD. We also investigate the entanglement PDC QKD with two-way classical communications. We find that the recurrence scheme increases the key rate and Gottesman-Lo protocol helps tolerate higher channel losses. By simulating a recent 144km open-air PDC experiment, we compare three implementations -entanglement PDC QKD, triggering PDC QKD and coherent state QKD. The simulation result suggests that the entanglement PDC QKD can tolerate higher channel losses than the coherent state QKD. The coherent state QKD with decoy states is able to achieve highest key rate in the low and medium-loss regions. By applying Gottesman-Lo two-way post-processing protocol, the entanglement PDC QKD can tolerate up to 70dB combined channel losses (35dB for each channel) provided that the PDC source is placed in between Alice and Bob. After considering statistical fluctuations, the PDC setup can tolerate up to 53dB channel losses.

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“…Eve's attack will modify the statistical characteristics of the decoy states and/or signal state and will be detected. As practical experiments have shown for these protocols (as for the SARG04 protocol), the key rate and practical length of the channel is bigger than for BB84 protocols (Peng et al, 2007;Rosenberg et al, 2007;Zhao et al, 2006). Nevertheless, it is necessary to notice that using these protocols, as well as the others considered above, it is also impossible without users pre-authentication to construct the complete high-grade solution of the problem of key distribution.…”

Section: Main Approaches To Quantum Secure Telecommunication Systems mentioning

confidence: 99%

“…QKD includes the following protocols: protocols using single (non-entangled) qubits (two-level quantum systems) and qudits (d-level quantum systems, d>2) (Bennett, 1992;Bennett et al, 1992;Bourennane et al, 2002;Bruss & Macchiavello, 2002;Cerf et al, 2002;Gnatyuk et al, 2009); protocols using phase coding (Bennett, 1992); protocols using entangled states (Ekert, 1991;Durt et al, 2004); decoy states protocols (Brassard et al, 2000;Liu et al, 2010;Peng et al, 2007;Yin et al, 2008;Zhao et al, 2006aZhao et al, , 2006b; and some other protocols (Bradler, 2005;Lütkenhaus & Shields, 2009;Navascués & Acín, 2005;Pirandola et al, 2008).…”

Section: Main Approaches To Quantum Secure Telecommunication Systems mentioning

confidence: 99%

“…Another way of protecting against photon number splitting attack is the use of decoy states QKD protocols (Brassard et al, 2000;Peng et al, 2007;Rosenberg et al, 2007;Zhao et al, 2006), which are also advanced types of BB84 protocol. In such protocols, besides information signals Alice's source also emits additional pulses (decoys) in which the average photon number differs from the average photon number in the information signal.…”

Section: Main Approaches To Quantum Secure Telecommunication Systems mentioning

confidence: 99%

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