Optical quantum random number generator based on orbital angular momentum of light

Mujtaba Zahidy, Hamid Tebyanian, Daniele Cozzolino +5 more

Genuine random numbers can be produced beyond a shadow of doubt through the intrinsic randomness provided by quantum mechanics theories. While many degrees of freedom have been investigated for randomness generation, adequate attention has not been paid to the orbital angular momentum of light. In this work, we present a quantum random number generator based on the intrinsic randomness inherited from the superposition of orbital angular momentum modes caused by the cross talk inside a ring-core fiber. We studied two possible cases: a first one, device-dependent, where the system is trusted, and a second one, semi-device-independent, where the adversary can control the measurements. We experimentally realized the former, extracted randomness, and, after privacy amplification, we achieved a generation rate higher than 10 Mbit/s. In addition, we presented a possible realization of the semi-device-independent protocol using a newly introduced integrated silicon photonic chip. Our work can be considered as a starting point for novel investigation of quantum random number generators based on the orbital angular momentum of light.

鄢秋荣 Yan Qiurong, 赵宝升 Zhao Baosheng, 刘永安 +1 more

André Stefanov, Nicolas Gisin, Olivier Guinnard +2 more

Michael De Oliveira, Nicholas Bornman, Andrew Forbes

We present a quantum random number generator (QRNG) based on the random outcomes inherent in projective measurements on a superposition of quantum states of light. First, we use multiplexed holograms encoded on a spatial light modulator to spatially map down-converted photons onto a superposition of optical paths. This gives us full digital control of the mapping process which we can tailor to achieve any desired probability distribution. More importantly, we use this method to account for any bias present within our transmission and detection system, forgoing the need for time-consuming and inefficient unbiasing algorithms. Our QRNG achieved a min-entropy of ${H}_{\text{min}}=0.9991\ifmmode\pm\else\textpm\fi{}0.0003$ bits per photon and passed the NIST Statistical Test Suite. Furthermore, we extend our approach to realize a QRNG based on photons entangled in their orbital angular momentum (OAM) degree of freedom. This combination of digital holograms and projective measurements on arbitrary OAM combinations allowed us to generate random numbers with arbitrary distributions, in effect tailoring the system's entropy while maintaining the inherent quantum irreproducibility. Such techniques allow access to the higher-dimensional OAM Hilbert space, opening up an avenue for generating multiple random bits per photon.

鄢秋荣 YAN Qiu-rong, 赵宝升 ZHAO Bao-sheng, 张华 ZHANG Hua +2 more

Xizheng Ke

The nondiffracting higher-order Bessel beams carry the orbital angular momentum(OAM). During free propagation,their transverse intensity profile remains nearly invariant in a range.The beam comprises the topological charge l helical phasefronts and carries an orbital angular momentum of lh per photon.The angular momentum number carried by the photon in each eigenmode is represented by l, and the eigenstates |l〉can generate multidimensional quantum entangled states.A method of optical communication is presented that encodes information in two orthogonal orbital angular momentum states based on higher-order Bessel beams.Each photon carries OAM states of information,which can increase the key generation rate of the protocol,and offer a quantum solution for increase of the optical communication distance.