The Hong-Ou-Mandel effect is considered a signature of the quantumness of light, as the dip in coincidence probability using semiclassical theories has an upper bound of 50%. Here we show, theoretically and experimentally, that, with proper phase control of the signals, classical pulses can mimic a Hong-Ou-Mandel-like dip. We demonstrate a dip of (99.635 ± 0.002)% with classical microwave fields. Quantumness manifests in wave-particle complementarity of the two-photon state. We construct quantum and classical interferometers for the complementarity test and show that while the two-photon state shows wave-particle complementarity the classical pulses do not. * usinha@rri.res.in arXiv:1810.01297v3 [quant-ph]

Higher dimensional quantum systems have a very important role to play in quantum information, computation as well as communication. While the polarization degree of freedom of the photon is a common choice for many studies, it is restricted to only two orthogonal states, hence qubits for manipulation. In this paper, we theoretically model as well as experimentally verify a novel scheme of approximating photonic qutrits by modulating the pump beam in a spontaneous parametric down conversion process using a three-slit aperture. The emerging bi-photon fields behave like qutrits and are found to be highly correlated in the spatial degree of freedom and effectively represent spatially correlated qutrits with a Pearson coefficient as high as 0.9. In principle, this system provides us a scalable architecture for generating and experimenting with higher dimensional correlated qudits.

Higher dimensional quantum systems (qudits) present a potentially more efficient means, compared to qubits, for implementing various information theoretic tasks. One of the ubiquitous resources in such explorations is entanglement. Entanglement Monotones (EMs) are of key importance, particularly for assessing the efficacy of a given entangled state as a resource for information theoretic tasks. Till date, investigations towards determination of EMs have focused on providing their tighter lower bounds. There is yet no general scheme available for direct determination of the EMs. Consequently, an empirical determination of any EM has not yet been achieved for entangled qudit states. The present paper fills this gap, both theoretically as well as experimentally. First, we derive analytical relations between statistical correlation measures i.e. Mutual Predictability (MP), Mutual Information (MI) and Pearson Correlation Coefficient (P CC) and standard EMs i.e. Negativity (N ) and Entanglement of Formation (E OF ) in arbitrary dimensions. As a proof of concept, we then experimentally measure MP, MI and P CC of two-qutrit pure states and determine their N and E OF using these derived relations. This is a useful addition to the experimenter's toolkit wherein by using a limited number of measurements (in this case 1 set of measurements), one can directly measure the EMs in a bipartite arbitrary dimensional system. We obtain the value of N for our bipartite qutrit to be 0.907 ± 0.013 and the E OF to be 1.323 ± 0.022. Since the present scheme enables determination of more than one entanglement monotone by the same limited number of measurements, we argue that it can serve as a unique experimental platform for quantitatively comparing and contrasting the operational implications of entanglement monotones as well as showing their non-monotonicity for a given bipartire pure qudit state.

Higher dimensional quantum systems are an important avenue for new explorations in quantum computing as well as quantum communications. One of the ubiquitous resources in quantum technologies is entanglement. However, so far, entanglement has been certified in higher dimensional systems through suitable bounds on known entanglement measures. In this work, we have, for the first time, quantified the amount of entanglement in bi-partite pure qutrit states by analytically relating statistical correlation measures and known measures of entanglement, and have determined the amount of entanglement in our experimentally generated spatially correlated bi-partite qutrit system. We obtain the value of Negativity in our bi-partite qutrit to be 0.85 ± 0.03 and the Entanglement of Formation (EOF) to be 1.23 ± 0.01. In terms of quantifying the deviation from the maximally entangled state, the Negativity value demonstrates ∼ 15% deviation while the EOF value demonstrates ∼ 24% deviation. This serves as the first experimental evidence of such non-equivalence of entanglement measures for higher dimensional systems.

With increasing technologies and scientific knowledge, today’s world has resulted in a great change in almost all aspects. Technical facilities, machine learning, algorithms and other aspects are playing a huge role in almost every part of the world. Taking this into consideration, this research was developed by us, which includes face recognition, face detection and feature extraction. This research is based on real time face recognition for attendance, as it may help in huge number of institutions and other sectors. Here no physical involvement of invigilator is required. The system will totally conduct the processes based on better internet connection and better illumination. An extra feature has been added which includes the details of the pupil to be emailed to their guardian. It’s undertaking is done with Python 3.7.6, OpenCV 3.4. and Anaconda Navigator(Anaconda3). The proposed arrangement is tried for different light intensities and conditions.