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Basherrudin Mahmud Ahmed A

Publications and source records attributed to Basherrudin Mahmud Ahmed A.

3 recordsLinked to original sources

Unified Framework for Bidirectional and Cyclic Teleportation under Noise

Quantum teleportation has evolved from single-qubit, unidirectional communication to multi-qubit and multidirectional protocols. However, most existing schemes rely on protocol-specific entangled resources, motivating the development of universal quantum channels capable of supporting multiple communication tasks simultaneously. In this work, we demonstrate that a single twelve-qubit entangled channel exhibits such versatility by enabling the bidirectional teleportation of arbitrary three-qubit states and the cyclic teleportation of arbitrary two-qubit states through local Bell-state measurements and single-qubit operations. Both protocols are further generalized to multi-qubit and multi-party configurations, establishing the scalability of the proposed framework. To assess its practical applicability, the protocols are analyzed under amplitude-damping, phase-damping, bit-flip, phase-flip, and depolarizing noise channels by plotting the teleportation fidelity as a function of both the input-state parameters and noise strength. The analysis reveals distinct noise sensitivities, with the bidirectional protocol remaining perfectly faithful under bit-flip noise for all input states and noise strengths, while the cyclic protocol is consistently more vulnerable to environmental disturbances. The proposed schemes achieve an intrinsic efficiency of $25\%$, which is compared with several existing protocols. The framework therefore provides a scalable and resource-efficient approach to unified quantum communication in realistic noisy quantum networks.

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Enhanced Two-Way Teleportation of Entangled States with Six-Qubit Cluster State

This work presents a two-way teleportation protocol for the transfer of an unknown two-qubit quantum state between two parties Alice and Bob, utilizing a six-qubit cluster state. This bidirectional exchange is achieved by performing Bell measurements on the qubit pairs of Alice and Bob, ensuring the successful teleportation of the quantum state for both parties. We demonstrate the proposed protocol by designing a teleportation circuit that incorporates the necessary quantum gates. The fidelity of the teleportation process is evaluated through simulations, confirming the accuracy and reliability of the proposed scheme. The protocol restores teleported states without requiring CNOT operations or auxiliary qubits, offering a significant advantage in resource efficiency(utilization). A comparative analysis of the intrinsic efficiency with previous approaches establishes that the proposed protocol brings forth an efficient approach for achieving two-way quantum teleportation.

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Squeezing in conditional measurement setup with coherent input

Conditional Measurement scheme which employs linear optical elements and photon detection is the fertile ground for nonclassical state generation. We consider a simple setup that requires a coherent state and a number state as inputs of the beam splitter, and a photon detector. We show that by tuning the parameters involved in the setup, we can achieve optimal squeezing from the setup. This is facilitated by writing the output state of the conditional measurement as displaced qudits. Setting aside displacement which plays no role in squeezing, the finite-dimensional representation makes it possible to calculate the maximal amount of squeezing. By fixing the detection at one photon level irrespective of any number state input and carefully chosen coherent parameter and beam splitter reflectivity values, one can reach the maximal squeezing at least for lower number state inputs. This is in contrast to the earlier attempts in atom field interaction models etc., where the squeezing obtained was far from saturation. To accommodate the experimental imperfections, we consider the impure nature of the photon source and detector inefficiency.

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