Blogging in Planck Time
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Can all NP problems be efficiently solved in quantum polynomial time?
The Bennett–Bernstein–Brassard–Vazirani 1997 (BBBV97) paper, titled “Strengths and Weaknesses of Quantum Computing”, has had a profound and enduring impact on both theoretical computer science and cryptography. By clarifying the limitations of quantum advantage, BBBV97 indirectly influenced cryptographers to recognize that not all classical problems are vulnerable to quantum attacks. Coupled with Shor’s algorithm showing polynomial-speed… -
Quantum Information Processing
“Central to many recent quantum algorithms is the ability to reduce high-dimensional operators to SU(2) building blocks, manipulate them with phase rotations, and then lift the resulting polynomial back to the original space.” 1 Prelude: Why these three ideas? Cosine–sine decomposition (CSD) gives an explicit, numerically stable way to factor a unitary (or a tall…