Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum Counterfeit Coin Problems   The counterfeit coin problem requires us to find all false coins from a given
bunch of coins using a balance scale. We assume that the balance scale gives us
only ``balanced'' or ``tilted'' information and that we know the number k of
false coins in advance. The balance scale can be modeled by a certain type of
oracle and its query complexity is a measure for the cost of weighing
algorithms (the number of weighings). In this paper, we study the quantum query
complexity for this problem. Let Q(k,N) be the quantum query complexity of
finding all k false coins from the N given coins. We show that for any k and N
such that k < N/2, Q(k,N)=O(k^{1/4}), contrasting with the classical query
complexity, \Omega(k\log(N/k)), that depends on N. So our quantum algorithm
achieves a quartic speed-up for this problem. We do not have a matching lower
bound, but we show some evidence that the upper bound is tight: any algorithm,
including our algorithm, that satisfies certain properties needs
\Omega(k^{1/4}) queries.

6
The categories of this paper are: astro-ph
19
The categories of this paper are: eess
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
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The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
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The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an