“Deferred Measurement Principle”的意思、由来-开放百科全书

The Deferred Measurement Principle is a result in quantum computing which states that delaying measurements until the end of a quantum computation doesn't affect the probability distribution of outcomes.^[1]^[2]

A consequence of the deferred measurement principle is that measuring commutes with conditioning.

The choice of whether to measure a qubit before, after, or during an operation conditioned on that qubit will have no observable effect on a circuit's final expected results.

Thanks to the deferred measurement principle, measurements in a quantum circuit can often be shifted around so they happen at better times.

For example, measuring qubits as early as possible can reduce the maximum number of simultaneously stored qubits; potentially enabling an algorithm to be run on a smaller quantum computer or to be simulated more efficiently.

Alternatively, deferring all measurements until the end of circuits allows them to be analyzed using only pure states.

References

1. ^{{cite book|author1=Michael A. Nielsen|author2=Isaac L. Chuang|title=Quantum Computation and Quantum Information: 10th Anniversary Edition|url=https://books.google.com/books?id=-s4DEy7o-a0C|date=9 December 2010|publisher=Cambridge University Press|isbn=978-1-139-49548-6 |page=186 |section=4.4 Measurement}}
2. ^{{cite book|author=Odel A. Cross|title=Topics in Quantum Computing|url=https://books.google.com/books?id=b_D9flK2h8QC&pg=PA348|date=5 November 2012|publisher=O. A. Cross|isbn=978-1-4800-2749-7|page=348 |section=5.2.2 Deferred Measurement}}