arXiv subjects

Ravi Sangwan

Publications and source records attributed to Ravi Sangwan.

3 recordsLinked to original sources

arXiv2026

Towards a Hybrid Quantum Enhanced Solution for Densest k-Subgraph Problem

We study the application of Gaussian Boson Sampling (GBS) to the densest k-subgraph problem (DkSP). GBS with hard post-selection suffers from poor sampling efficiency due to strict cardinality constraints. To address this limitation, we introduce effective classical post-processing strategies that transform, otherwise discarded, near-k samples into feasible solutions. A comprehensive set of simulations is carried out, demonstrating that these approaches achieve near-optimal solution quality while improving sampling efficiency by approximately 4X compared to post-selection on community-structured graphs, and also post-selection often fails to reach the optimal solution on sparse random graphs even with large number of samples. Furthermore, the proposed methods perform on par with, and in some cases outperform, established classical approaches for graphs up to moderate size. Overall, the results indicate that while GBS with post-selection alone is insufficient, its combination with lightweight classical refinement can be highly effective. This underscores the potential of hybrid quantum-classical frameworks and positions GBS as a promising sampling primitive for combinatorial graph optimization.

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arXiv2025

Single-Round Deterministic Quantum Anonymous Veto Using Bell States

Quantum Anonymous Veto (QAV) protocols enable secure and anonymous decision-making by allowing participants to detect the presence of a veto without revealing individual choices. While existing QAV schemes offer strong theoretical guarantees, they face significant limitations in practical implementation due to resource requirements, scalability issues, and the need for multipartite entanglement. In this work, we propose a novel deterministic QAV protocol that leverages only bipartite entanglement in the form of Bell states and achieves conclusive veto detection in a single round. Our approach eliminates the need for multi-qubit entangled states and iterative rounds, thereby significantly reducing experimental overhead and enhancing scalability. The protocol preserves critical properties such as voter anonymity, correctness, and verifiability, making it well-suited for implementation on near-term quantum devices. Furthermore, we outline a practical photonic realization based on polarization-path encoding and discrete-time quantum walks, demonstrating its feasibility within current quantum optical platforms. This work contributes a resource-efficient and experimentally viable alternative to existing QAV schemes, advancing the prospects of secure quantum decision-making in distributed systems.

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arXiv2025

Deutsch-Jozsa and Bernstein-Vazirani algorithm using single-particle discrete-time quantum walk

The paper introduces an efficient implementation of the Deutsch-Jozsa and Bernstein-Vazirani algorithm using the single-particle discrete-time quantum walk. We also provide a detailed optical framework with specific optical components to achieve these implementations in the photonic quantum walk scheme by simultaneously exploiting both polarization and path degrees of freedom. These implementations demonstrate improved resource efficiency while maintaining the exponential speedup characteristic of both algorithms. This work contributes to the growing field of universal quantum computing using single particle discrete-time quantum walk.

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