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Quantum Proof-of-Work: A Game Changer for Blockchain Consensus Mechanisms?

The researchers propose a quantum PoW scheme based on boson sampling that could significantly speed up and save energy in blockchain consensus mechanisms.

A team of researchers from universities in Australia and the United States, in collaboration with quantum technology company BTQ, have proposed a novel proof-of-work (PoW) blockchain consensus mechanism that leverages quantum computing. According to their recent research paper, this system, dubbed “Proof-of-work consensus by quantum sampling," could offer a significant speedup and energy savings compared to traditional computation methods.

Current PoW consensus algorithms, like the one Bitcoin uses, are notoriously energy inefficient and slow due to their requirement for substantial computational resources. In contrast, the proposed quantum PoW scheme based on boson sampling could provide a far more energy-efficient alternative when implemented on quantum hardware.

Boson sampling is not new, but its application to blockchain technology is novel. It is a non-universal quantum computing solution that has shown potential in specific domains like chemistry, and the researchers believe it could be the perfect solution for future-proofing blockchain applications and potentially reducing the environmental impact of Bitcoin mining.

The quantum advantage offered by this scheme could also increase the difficulty of mining, thereby maintaining a consistent block mining time as the number of miners increases. This would further incentivize the participation of "quantum miners."

Traditional supercomputers currently have an advantage over quantum systems in being able to "precompute" when dealing with the same class of problem regularly. However, in blockchain mining, precomputation offers no benefit as the problem is "progress-free." Regardless of how many times a blockchain puzzle is solved to provide PoW, the computer and algorithms don't improve at solving the problem.

In this scenario, despite the challenges and costs associated with developing and maintaining quantum computers, they could potentially validate blockchain consensus more efficiently than state-of-the-art classical systems.