The Quantum Communication Complexity of the Pointer Chasing Problem: The Bit Version
نویسندگان
چکیده
We consider the two-party quantum communication complexity of the bit version of the pointer chasing problem, originally studied by Klauck, Nayak, Ta-Shma and Zuckerman [KNTZ01]. We show that in any quantum protocol for this problem, the two players must exchange Ω( n k4 ) qubits. This improves the previous best bound of Ω( n 22 O(k) ) in [KNTZ01], and comes significantly closer to the best upper bounds knownO(n+k log n) (classical deterministic [PRV01]) andO(k logn+ nk (log (n)+log k)) (classical randomized [KNTZ01]). Our proof uses a round elimination argument with correlated input generation, making better use of the information theoretic tools than in previous papers.
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