منابع مشابه
The Learnability of Quantum States
Traditional quantum state tomography requires a number of measurements that grows exponentially with the number of qubits n. But using ideas from computational learning theory, we show that “for most practical purposes” one can learn a state using a number of measurements that grows only linearly with n. Besides possible implications for experimental physics, our learning theorem has two applic...
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We describe a quantum PAC learning algorithm for DNF formulae under the uniform distribution with a query complexity of Õ(s/ǫ+ s/ǫ), where s is the size of DNF formula and ǫ is the PAC error accuracy. If s and 1/ǫ are comparable, this gives a modest improvement over a previously known classical query complexity of Õ(ns/ǫ). We also show a lower bound of Ω(s logn/n) on the query complexity of any...
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Motivated by recent work on quantum black-box query complexity, we consider quantum versions of two wellstudied models of learning Boolean functions: Angluin’s model of exact learning from membership queries and Valiant’s Probably Approximately Correct (PAC) model of learning from random examples. For each of these two learning models we establish a polynomial relationship between the number of...
متن کاملThe learnability of unknown quantum measurements
Machine Learning (ML) [1–3] aims to systematically devise algorithms for machines to infer the input-output relationship of an unknown functional from historic data. More precisely, the key elements in ML are an input space X (a measurable space); an output space Y (a closed subset of real line), and a collection of functions, denoted as the hypothesis set F . The learning machine seeks to cons...
متن کاملThe Effect of Structural Parameters on the Electronic States and Oscillator Strength of a Resonant Tunneling Quantum Well Infrared Photodetector
In this paper a resonant tunnelling quantum well infrared photodetector (RT-QWIP) is discussed. Each period of this photodetector structure comprises of a resonant tunnelling structure (AlAs/AlGaAs/AlAs) nearby a quantum well (AlGaAs/GaAs). In this photodetector, photocurrent is produced when an electron makes a transition from the ground state of the well to an excited state which is coupled t...
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ژورنال
عنوان ژورنال: Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
سال: 2007
ISSN: 1364-5021,1471-2946
DOI: 10.1098/rspa.2007.0113