41,127 research outputs found
Natural evolution strategies and variational Monte Carlo
A notion of quantum natural evolution strategies is introduced, which
provides a geometric synthesis of a number of known quantum/classical
algorithms for performing classical black-box optimization. Recent work of
Gomes et al. [2019] on heuristic combinatorial optimization using neural
quantum states is pedagogically reviewed in this context, emphasizing the
connection with natural evolution strategies. The algorithmic framework is
illustrated for approximate combinatorial optimization problems, and a
systematic strategy is found for improving the approximation ratios. In
particular it is found that natural evolution strategies can achieve
approximation ratios competitive with widely used heuristic algorithms for
Max-Cut, at the expense of increased computation time
A quantum-inspired tensor network method for constrained combinatorial optimization problems
Combinatorial optimization is of general interest for both theoretical study
and real-world applications. Fast-developing quantum algorithms provide a
different perspective on solving combinatorial optimization problems. In this
paper, we propose a quantum inspired algorithm for general locally constrained
combinatorial optimization problems by encoding the constraints directly into a
tensor network state. The optimal solution can be efficiently solved by
borrowing the imaginary time evolution from a quantum many-body system. We
demonstrate our algorithm with the open-pit mining problem numerically. Our
computational results show the effectiveness of this construction and potential
applications in further studies for general combinatorial optimization
problems
Adiabatic evolution on a spatial-photonic Ising machine
Combinatorial optimization problems are crucial for widespread applications
but remain difficult to solve on a large scale with conventional hardware.
Novel optical platforms, known as coherent or photonic Ising machines, are
attracting considerable attention as accelerators on optimization tasks
formulable as Ising models. Annealing is a well-known technique based on
adiabatic evolution for finding optimal solutions in classical and quantum
systems made by atoms, electrons, or photons. Although various Ising machines
employ annealing in some form, adiabatic computing on optical settings has been
only partially investigated. Here, we realize the adiabatic evolution of
frustrated Ising models with 100 spins programmed by spatial light modulation.
We use holographic and optical control to change the spin couplings
adiabatically, and exploit experimental noise to explore the energy landscape.
Annealing enhances the convergence to the Ising ground state and allows to find
the problem solution with probability close to unity. Our results demonstrate a
photonic scheme for combinatorial optimization in analogy with adiabatic
quantum algorithms and enforced by optical vector-matrix multiplications and
scalable photonic technology.Comment: 9 pages, 4 figure
A Survey on Reinforcement Learning for Combinatorial Optimization
This paper gives a detailed review of reinforcement learning in combinatorial
optimization, introduces the history of combinatorial optimization starting in
the 1960s, and compares it with the reinforcement learning algorithms in recent
years. We explicitly look at a famous combinatorial problem known as the
Traveling Salesperson Problem (TSP). We compare the approach of the modern
reinforcement learning algorithms on TSP with an approach published in 1970.
Then, we discuss the similarities between these algorithms and how the approach
of reinforcement learning changes due to the evolution of machine learning
techniques and computing power. We also mention the deep learning approach on
the TSP, which is named Deep Reinforcement Learning. We argue that deep
learning is a generic approach that can be integrated with traditional
reinforcement learning algorithms and optimize the outcomes of the TSP.Comment: manuscript submitted to Management Scienc
Systems approaches and algorithms for discovery of combinatorial therapies
Effective therapy of complex diseases requires control of highly non-linear
complex networks that remain incompletely characterized. In particular, drug
intervention can be seen as control of signaling in cellular networks.
Identification of control parameters presents an extreme challenge due to the
combinatorial explosion of control possibilities in combination therapy and to
the incomplete knowledge of the systems biology of cells. In this review paper
we describe the main current and proposed approaches to the design of
combinatorial therapies, including the empirical methods used now by clinicians
and alternative approaches suggested recently by several authors. New
approaches for designing combinations arising from systems biology are
described. We discuss in special detail the design of algorithms that identify
optimal control parameters in cellular networks based on a quantitative
characterization of control landscapes, maximizing utilization of incomplete
knowledge of the state and structure of intracellular networks. The use of new
technology for high-throughput measurements is key to these new approaches to
combination therapy and essential for the characterization of control
landscapes and implementation of the algorithms. Combinatorial optimization in
medical therapy is also compared with the combinatorial optimization of
engineering and materials science and similarities and differences are
delineated.Comment: 25 page
Interface mapping in two-dimensional random lattice models
We consider two disordered lattice models on the square lattice: on the
medial lattice the random field Ising model at T=0 and on the direct lattice
the random bond Potts model in the large-q limit at its transition point. The
interface properties of the two models are known to be related by a mapping
which is valid in the continuum approximation. Here we consider finite random
samples with the same form of disorder for both models and calculate the
respective equilibrium states exactly by combinatorial optimization algorithms.
We study the evolution of the interfaces with the strength of disorder and
analyse and compare the interfaces of the two models in finite lattices.Comment: 7 pages, 6 figure
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