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Showing 1 to 20 of 27 for “"Quantum Algorithm"”.
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Effects of control error on an adiabatic quantum algorithm
Noise in adiabatic quantum computation can be modelled as a perturbation of the problem Hamiltonian. For a type of noise called control error, the perturbation can be considered to have the same structure as the problem Hamiltonian. If the problem Hamiltonian, and therefore the noise, are 2-local, …
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Machine Learning for Physics Applications: Quantum Algorithm Design, Chaotic Dynamics, and Mass Spectrometry
… optimisation as a tool for automated quantum algorithm design, where evolutionary search with a domain-specific language enables the synthesis of quantum algorithms that automatically scale to any problem size. By rediscovering known protocols such as the quantum Fourier transform, …
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Novel Quantum Chemistry Algorithms Based on the Variational Quantum Eigensolver
The variational quantum eigensolver (VQE) approach is currently one of the most promising strategies for simulating chemical systems on quantum hardware. In this work, I will describe a new quantum algorithm and a new set of classical algorithms based on VQE. The quantum algorithm, ADAPT-VQE, shows …
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Sampling Using Controlled Quantum Walks
We give a new quantum algorithm to sample from probability distributions over graph vertices quadratically faster than the optimal classical algorithm, which uses random walks with stopping rules. Efficient sampling is an important computational task used in simulations based on stochastic …
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Quantum Algorithms For String Problems
We design near-optimal quantum query algorithms for two important text processing problems: Longest Common Substring and Lexicographically Minimal String Rotation. Specifically, we show that: - Longest Common Substring can be solved by a quantum algorithm in Õ(n²⸍³) time, improving upon the …
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Foundational Abstractions for Quantum Programming
Bringing the promise of quantum computation into reality requires not only building a quantum computer but also correctly programming it to run a quantum algorithm. To obtain asymptotic advantage over classical algorithms for applications including simulation, search, and optimization, quantum …
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Cumulative effects in quantum algorithms and quantum process tomography
This thesis comprises three results on quantum algorithms and quantum process tomography. In the first section, I create a tool that uses properties of the quantum general adversary bound to upper bound the query complexity of Boolean functions. Using this tool I prove the existence of O(1)-query …
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Digital Quantum Computing for Many-Body Simulations
Abstract Iris The power of quantum computing lies in its ability to perform certain calculations and solve complex problems exponentially faster than classical computers. This potential has profound implications for a wide range of fields, including particle physics. This thesis lays a fundamental …
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Adiabatic processes, noise, and stochastic algorithms for quantum computing and quantum simulation
… provide promising platforms for realising quantum computation and quantum simulation. This, in turn, opens new possibilities for developing useful quantum algorithms and explaining complex many-body physics. The advantages of quantum computation have been demonstrated in a small range of …
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Evaluation of boolean formulas with restricted inputs
… thesis, I will investigate the running time of quantum algorithms for evaluating boolean functions when the input is promised to satisfy certain conditions. The two quantum algorithms considered in this paper are the quantum walk algorithm for NAND trees given by Farhi and Gutmann [2], and an …
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Practical Modern Quantum Programming
… we present a compiler for Cavy, an imperative quantum programming language. The main contribution of the Cavy system is the application of region inference to the problem of safe and efficient ancilla qubit allocation, use, and deallocation in a programming language with a reversible subset. …
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Quantum Algorithms and Complexity for Numerical Problems
Quantum computing has attracted a lot of attention in different research fields, such as mathematics, physics and computer science. Quantum algorithms can solve certain problems significantly faster than classical algorithms. There are many numerical problems, especially those arising from quantum …
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QAOA applied to the portfolio optimization problem
Quantum computing is no longer in its early stages. There already exists quantum computers with more qubits than a classical computer is capable of efficiently simulating. This current stage is considered intermediate and is therefore called the NISQ era (noisy intermediate-scale quantum). The main …
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Simulation algorithms, Floquet phenomena and superconducting qubits
… topics that span the abstraction stack of quantum computing: from physical properties of superconducting qubits to computational properties of algorithms for quantum simulation. In the introduction, we begin by reviewing the circuit model of quantum computing. We then introduce circuit …
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Tangled Circuits: Characterizing Errors in Experimental Superconducting Quantum Processors
… towards the first generation of error-corrected quantum computers based on physical quantum bits (qubits), researchers require robust techniques for designing, operating, and characterizing coupled multi-qubit systems in the laboratory, and for understanding the errors which arise in such …
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Quantum evolution: The case of weak localization for a 3D alloy-type Anderson model and application to Hamiltonian based quantum computation
Over the years, people have found Quantum Mechanics to be extremely useful in explaining various physical phenomena from a microscopic point of view. Anderson localization, named after physicist P. W. Anderson, states that disorder in a crystal can cause non-spreading of wave packets, which is one …
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Open quantum system dynamics for describing state transfer
<p>In principle a quantum system could be used to simulate another quantum system. The purpose of such a simulation would be to obtain information about problems which are difficult to simulate on a classical computer due to the exponential increase of the Hilbert space with the size of the system, …
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Application of quantum walks on graph structures to quantum computing
Quantum computation is a new computational paradigm which can provide fundamentally faster computation than in the classical regime. This is dependent on finding efficient quantum algorithms for problems of practical interest. One of the most successful tools in developing new quantum algorithms is …
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Case studies in quantum adiabatic optimization
Quantum adiabatic optimization is a quantum algorithm for solving classical optimization problems (E. Farhi, J. Goldstone, S. Gutmann, and M. Sipser. Quantum computation by adiabatic evolution, 2000. arXiv:quant-ph/0001106). The solution to an optimization problem is encoded in the ground state of …
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Contributions to Information-Based Complexity and to Quantum Computing
… studied in the literature. On the other hand the quantum computational model presents a promising alternative for dealing with multivariate problems. The idea of using quantum mechanics to simulate quantum physics was initially proposed by Feynman in 1982. Its potential was demonstrated by Shor's …
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