aiqbench takeQuantum Computing

The paper proposes encoding complex amplitudes using CORDIC to compute magnitude and argument from binary registers, which yields smaller normalisation constants than LCU and allows arithmetic in polar form before state preparation. For quantum algorithm developers, the practical question is whether the claimed reduction in amplitude amplification steps holds up in full resource accounting, including T-gate counts and classical preprocessing. Readers should treat the reported gains as results for this specific encoding approach until independent benchmarks or comparisons on realistic problem sizes are available.

Source coveringQuantum Zeitgeist

Waterloo Team Prepares Complex Amplitudes Using Fewer Qubits

Quantum ZeitgeistOctober 30, 20263 min read

Can complex numbers be efficiently encoded onto quantum systems without incurring substantial overhead? This work introduces a method that computes magnitude and argument using established digital techniques, reducing normalisation compared to standard linear combination methods. Retaining this ‘polar’ form then uniquely enables extra quantum calculations *before* final state preparation.

The paper details a new procedure for preparing quantum states that encodes complex numbers into amplitudes using an algorithm called CORDIC; this computes magnitude and argument from binary registers representing real and imaginary parts. This approach allows smaller normalization than existing methods like LCU, reducing costs during amplitude amplification, and also calculates polar representation enabling further arithmetic before encoding. These underpin many quantum…

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