Efficient heralding of photonic qubits with applications to device-independent quantum key distribution

Abstract

We present an efficient way of heralding photonic qubit signals using linear optics devices. First, we show that one can obtain asymptotically perfect heralding and unit success probability with growing resources. Second, we show that even using finite resources, we can improve qualitatively and quantitatively over earlier heralding results. In the latter scenario, we can obtain perfect heralded photonic qubits while maintaining a finite success probability. We demonstrate the advantage of our heralding scheme by predicting key rates for device-independent quantum key distribution, taking imperfections of sources and detectors into account

Distilling single-photon entanglement from photon loss and decoherence

“…Curty and Moroder discussed the heralded-qubit amplifier for practical device-independent quantum key distribution [38]. Pitkanen also presented an efficient way for heralding photonic qubit signals using linear optics devices [39]. Recently, Osorio et al reported their experimental result for heralded noiseless amplification based on singlephoton sources and linear optics [40].…”

Entanglement-based linear-optical qubit amplifier

“…In this case a projection on a Bell state in the middle of the communication line removes all detector side channels * Electronic address: bartkiewicz@jointlab.upol.cz † Electronic address: k.lemr@upol.cz are removed. The more complete approach is deviceindependent QKD (DI-QKD) [12][13][14][15][16] and its security is based on the loophole-free violation of a Bell inequality. DI-QKD removes all source and detector side channels but requires closing of the detector (high-efficiency detection) and locality (distant detectors) loopholes, which…”

Efficient amplification of photonic qubits by optimal quantum cloning

“…The amplifier works with an arbitrary gain (increase in of the probability of registering a photon) without introducing noise, but the probability of successfully heralding event is decreases as the gain is increased. In the case of the originall proposal, perfect gain could have been reached only asymptotically, however this shortcomming has been removed by Pitkanen et al [7]. Recently, it has been shown that, if a heralded amplifier is allowed to introduce some noise, its gain and herading rate be increased [10] which also depends on the set of qubits to be amplified.…”

“…The heralded amplifier and its improvments (see, eg., Ref. [7]) or alternarive schemes using entanglement [8][9][10] have been demonstrated to be useful especially in the * bark@amu.edu.pl context of quantum key distribution. Interesingly the improved qubit amplifier described in Ref.…”