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Entropy lower bounds for quantum decision tree complexity

✍ Scribed by Yaoyun Shi


Publisher
Elsevier Science
Year
2002
Tongue
English
Weight
70 KB
Volume
81
Category
Article
ISSN
0020-0190

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✦ Synopsis


We prove a general lower bound of quantum decision tree complexity in terms of some entropy notion. We regard decision tree computation as a communication process in which the oracle and the computer exchange several rounds of messages, each round consisting of O(log n) bits. Let E(f ) be the Shannon entropy of the random variable f (X), where X is taken uniformly random in f 's domain. Our main result is that it takes (E(f )) queries to compute any total function f . It is interesting to contrast this bound with the (E(f )/ log n) bound, which is tight for some partial functions.


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