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I. P. Degiovanni

Publications and source records attributed to I. P. Degiovanni.

58 records · Page 4Linked to original sources
arXiv2003

Coupling Efficiencies in Single Photon On-Demand Sources

Many quantum computation and communication schemes require, or would significantly benefit from, true sources of single photon on-demand (SPOD). Unfortunately, such sources do not exist. It is becoming increasingly clear that coupling photons out of a SPOD source will be a limiting factor in many SPOD implementations. In particular, coupling these source outputs into optical fibers (usually single mode fibers) is often the preferred method for handling this light. We investigate the practical limits to this coupling as relates to parametric downconversion, an important starting point for many SPOD schemes. We also explored whether it is possible to optimize the engineering of the downconversion sources to improve on this coupling. We present our latest results in this area.

quant-ph↗
arXiv2003

Experimental Eavesdropping Attack against Ekert's Protocol based on Wigner's Inequality

We experimentally implemented an eavesdropping attack against the Ekert protocol for quantum key distribution based on the Wigner inequality. We demonstrate a serious lack of security of this protocol when the eavesdropper gains total control of the source. In addition we tested a modified Wigner inequality which should guarantee a secure quantum key distribution.

quant-ph↗
arXiv2003

Quantum and Classical Noise in Practical Quantum Cryptography Systems based on polarization-entangled photons

Quantum-cryptography key distribution (QCKD) experiments have been recently reported using polarization-entangled photons. However, in any practical realization, quantum systems suffer from either unwanted or induced interactions with the environment and the quantum measurement system, showing up as quantum and, ultimately, statistical noise. In this paper, we investigate how ideal polarization entanglement in spontaneous parametric downconversion (SPDC) suffers quantum noise in its practical implementation as a secure quantum system, yielding errors in the transmitted bit sequence. Because all SPDC-based QCKD schemes rely on the measurement of coincidence to assert the bit transmission between the two parties, we bundle up the overall quantum and statistical noise in an exhaustive model to calculate the accidental coincidences. This model predicts the quantum-bit error rate and the sifted key and allows comparisons between different security criteria of the hitherto proposed QCKD protocols, resulting in an objective assessment of performances and advantages of different systems.

quant-ph↗