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تسجيل مستخدم جديدCanonical Construction of Quantum Oracles
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Selecting a set of basis states is a common task in quantum computing, in order to increase and/or evaluate their probabilities. This is similar to designing WHERE clauses in classical database queries. Even though one can find heuristic methods to achieve this, it is desirable to automate the process. A common, but inefficient automation approach is to use oracles with classical evaluation of all the states at circuit design time. In this paper, we present a novel, canonical way to produce a quantum oracle from an algebraic expression (in particular, an Ising model), that maps a set of selected states to the same value, coupled with a simple oracle that matches that particular value. We also introduce a general form of the Grover iterate that standardizes this type of oracle. We then apply this new methodology to particular cases of Ising Hamiltonians that model the zero-sum subset problem and the computation of Fibonacci numbers. In addition, this paper presents experimental results obtained on real quantum hardware, the new Honeywell computer based on trapped-ion technology with quantum volume 64.
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A standard quantum oracle $S_f$ for a general function $f: Z_N to Z_N $ is defined to act on two input states and return two outputs, with inputs $ket{i}$ and $ket{j}$ ($i,j in Z_N $) returning outputs $ket{i}$ and $ket{j oplus f(i)}$. However, if $f
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We study to what extent quantum algorithms can speed up solving convex optimization problems. Following the classical literature we assume access to a convex set via various oracles, and we examine the efficiency of reductions between the different o
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his model captures more of the difficulty of certain natural problems. We test this model on a simple problem, Search with Two Oracles, for which we create a quantum algorithm that we prove is asymptotically optimal. We further give some evidence, using a geometric picture of Grovers algorithm, that our algorithm is exactly optimal.
Noisy, intermediate-scale quantum (NISQ) computing devices offer opportunities to test the principles of quantum computing but are prone to errors arising from various sources of noise. Fluctuations in the noise itself lead to unstable devices that u
ndermine the reproducibility of NISQ results. Here we characterize the reliability of NISQ devices by quantifying the stability of essential performance metrics. Using the Hellinger distance, we quantify the similarity between experimental characterizations of several NISQ devices by comparing gate fidelities, duty cycles, and register addressability across temporal and spatial scales. Our observations collected over 22 months reveal large fluctuations in each metric that underscore the limited scales on which current NISQ devices may be considered reliable.
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Angela Sara Cacciapuoti
, Marcello Caleffi
, Francesco Tafuri andn Francesco Saverio Cataliotti
2018
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