Related topics: physical review letters

Researchers provide new method to boost clean energy research

Electrochemical energy systems—processes by which electrical energy is converted to chemical energy—are at the heart of establishing more efficient generation and storage of intermittent energy from renewable sources ...

Converting biomass by applying mechanical force

One of the greatest global challenges is the efficient use of renewable sources in order to meet the increasing demand for energy and feedstock chemicals in the future. In this context, biomass is a promising alternative ...

Scientists discover new 'architecture' in corn

New research on the U.S.'s most economically important agricultural plant—corn—has revealed a different internal structure of the plant than previously thought, which can help optimize how corn is converted into ethanol.

Deep learning for electron microscopy

Finding defects in electron microscopy images takes months. Now, there's a faster way. It's called MENNDL, the Multinode Evolutionary Neural Networks for Deep Learning. It creates artificial neural networks—computational ...

page 1 from 23

Perturbation theory (quantum mechanics)

In quantum mechanics, perturbation theory is a set of approximation schemes directly related to mathematical perturbation for describing a complicated quantum system in terms of a simpler one. The idea is to start with a simple system for which a mathematical solution is known, and add an additional "perturbing" Hamiltonian representing a weak disturbance to the system. If the disturbance is not too large, the various physical quantities associated with the perturbed system (e.g. its energy levels and eigenstates) can, from considerations of continuity, be expressed as 'corrections' to those of the simple system. These corrections, being 'small' compared to the size of the quantities themselves, can be calculated using approximate methods such as asymptotic series. We can therefore study the complicated system based on our knowledge of the simpler one.

This text uses material from Wikipedia, licensed under CC BY-SA