Tittel W, Brendel J, Zbinden H, Gisin N
Group of Applied Physics, University of Geneva, CH-1211, Geneva 4, Switzerland.
Phys Rev Lett. 2000 May 15;84(20):4737-40. doi: 10.1103/PhysRevLett.84.4737.
We present a setup for quantum cryptography based on photon pairs in energy-time Bell states and show its feasibility in a laboratory experiment. Our scheme combines the advantages of using photon pairs instead of faint laser pulses and the possibility to preserve energy-time entanglement over long distances. Moreover, using four-dimensional energy-time states, no fast random change of bases is required in our setup: Nature itself decides whether to measure in the energy or in the time base, thus rendering eavesdropper attacks based on "photon number splitting" less efficient.
我们展示了一种基于能量 - 时间贝尔态光子对的量子密码学设置，并在实验室实验中证明了其可行性。我们的方案结合了使用光子对而非微弱激光脉冲的优势以及在长距离上保持能量 - 时间纠缠的可能性。此外，使用四维能量 - 时间态，在我们的设置中不需要快速随机改变基：自然本身决定是在能量基还是时间基上进行测量，从而使基于“光子数分裂”的窃听者攻击效率降低。
