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Q: Quantenoptik und Photonik

Q 76: Poster Quantenkommunikation

Q 76.8: Poster

Donnerstag, 16. März 2006, 16:30–18:30, Labsaal

Quantum key distribution with decoy states generated by photon number resolution — •Wolfgang Mauerer and Christine Silberhorn — University Erlangen-Nuremberg, Max-Planck Research Group IOIP, Integrated Quantum Optics Group

We present ongoing work on the security analysis of a novel quantum key distribution scheme (QKD) based on parametric downconversion with photon number resolving detectors (PNRDs) used to select decoy states. Although a growing number of security proofs for QKD schemes is available for different scenarios, it is still hard to realise such schemes in practice without introducing security flaws which are not considered in the theoretical description. Additionally, the efficiency of most schemes quickly fades away when longer distances and thus increased losses are taken into account. Possible countermeasures are setups which are simple and robust to implement and the use of decoy states; both form the core of our scheme.

We use the properties of a recently devised PNRD[1] to generate decoy states[2] by conditioning the decoy state preparation on the result of the photon number measurement (PNM). We expect this to be more efficient than signal state preparation based on the PNM as used by Ref.[3]; additionally, our scheme should be easier to implement in practice than other decoy state schemes because no active optical elements are necessary for our approach.

[1] H.-K. Lo, X. Ma, K. Chen, Physical Review Letters 94, 230504 (2005)

[2] D. Achilles et al., J. Mod. Opt. 51, 1499 (2004)

[3] T. Horikiri et al., Phys. Rev. A 72, 012312 (2005)