SACM - India
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14154/68938
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Item Restricted Analysis of Image-Sensor Based Random Number Generators(Indian Institute of Technology Madras, 2023-09) Shafi, Albaraa; Prahbakar, AnilRandom number generators (RNGs) generate output based on an entropy seed which can be generated by sampling natural processes. Quantum RNGs (QRNGs) generate true random numbers by extracting entropy from quantum systems that are inherently probabilistic. One way to do this is to collect quantum entropy from signals generated by complementary metal-oxide-semiconductor (CMOS) Image Sensors (CISs) while detecting photons emitted through radiative recombination in light-emitting diodes (LEDs). Here, we propose a framework for determining and setting up an RNG based on spontaneous emission and shot noise due to photon absorption using affordable commercial-off-the-shelf (COTS) CISs and LEDs. To verify the entropy of such RNG, we developed a performance analysis methodology based on the second-order correlation function, cross-correlation, and mutual information to study the spatial correlations on the CIS output. Our research makes implementing RNGs using COTS components easy, thereby increasing their adoption and use in various applications. We applied our methodology using COTS components and compared our results against the NIST SP 800-90B entropy estimation suite. Furthermore, we extracted the entropy using the Toeplitz-hashing function to generate truly random numbers. We tested more than 140 GB of random data using the Dieharder testing suite and passed all statistical tests.26 0Item Restricted A Versatile Entanglement-Based Quantum Communication Network(Saudi Digital Library, 2023-04-28) Alwehaibi, Yazeed Khalid; Prabhakar, AnilEntanglement generation and distribution lie at the heart of quantum information science and technology. In particular, the observation of nonlocal correlations between quantum particles is an essential part of implementing quantum networks. The practical realization of such networks requires the use of fiber-based entangled photon-pair sources with a large bandwidth for easy integration with existing fiber networks as well as increased connectivity using the mature technology of wavelength-division-multiplexing (WDM). Here, we present an entanglement distribution scheme for quantum networks that utilizes a commercially available broadband entangled photon source and WDM technology. The design incorporates an efficient time-multiplexing technique to analyze the polarization correlations and calculate the visibility. In the context of the BBM92 protocol, we explore the trade-off between critical parameters such as the coincidence window, visibility, number of multiplexed wavelength channels, and the key rate. In addition, we discuss different network topologies and their advantages and disadvantages. In a tree-type network configuration, secret key rates between 2.1 and 3.2 bits/s were achievable among four users, with the prospect of scaling up. This study provides valuable insights into the design and implementation of practical and scalable quantum networks.9 0Item Restricted Coherent Optical Communication Techniques for Experimental Continuous-Variable Quantum Key Distribution(Saudi Digital Library, 2023-07-04) Alsaui, Abdulmohsen Abdulmalik; Venkitesh, DeepaThis work presents the details of implementing a continuous-variable quantum key distribution (CV-QKD) system using coherent reception. The research investigates factors that influence the secret key rate (SKR) in a practical setting, such as laser phase noise, hardware imperfections, and the considered security model. In addition, the study employs signal processing algorithms typically used in coherent optical communication utilizing homodyne detection. The experiment results demonstrate the proposed system’s feasibility and highlight the importance of considering practical limitations when implementing CV-QKD in real-world applications. Overall, this work contributes to the advancement of quantum communication technology and lays the foundation for CV-QKD field implementation.23 0