SWAP-test
A quantum circuit primitive for estimating the overlap (squared inner product) of two quantum states. Using an ancillary qubit and a controlled-SWAP gate, it converts the similarity of the two states into an observable interference pattern, from which an estimate is obtained through repeated sampling and statistics.
Timeline (last 90 days)
The research team deployed the trained circuits on Quantinuum's System Model H2 quantum computer and its accompanying simulator, executing similarity comparisons using a SWAP-test-based protocol.
The SWAP-test is a quantum circuit primitive for estimating the overlap (squared inner product) of two quantum states, which, with the aid of an auxiliary qubit and controlled-SWAP gates, converts the similarity of the two states into observable interference fringes on the auxiliary qubit.
The SWAP-test faces challenges on current noisy intermediate-scale quantum (NISQ) hardware: controlled-SWAP gates have relatively deep depth, and decoherence and gate errors weaken the contrast of the interference fringes, thereby underestimating the similarity.
All Facts (3)
The SWAP-test is a quantum circuit primitive for estimating the overlap (squared inner product) of two quantum states, which, with the aid of an auxiliary qubit and controlled-SWAP gates, converts the similarity of the two states into observable interference fringes on the auxiliary qubit.
50%UnverifiedThe SWAP-test faces challenges on current noisy intermediate-scale quantum (NISQ) hardware: controlled-SWAP gates have relatively deep depth, and decoherence and gate errors weaken the contrast of the interference fringes, thereby underestimating the similarity.
50%UnverifiedThe research team deployed the trained circuits on Quantinuum's System Model H2 quantum computer and its accompanying simulator, executing similarity comparisons using a SWAP-test-based protocol.
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