Related topics: physical review letters

Atomic-scale tailoring of graphene approaches macroscopic world

Properties of materials are often defined by imperfections in their atomic structure, especially when the material itself is just one atom thick, such as graphene. Researchers at the University of Vienna have now developed ...

Engineering matter at the atomic level

As the miniaturization of technology continues, scientists are seeking to engineer materials at the atomic level. In Nature Communications, researchers from the RIKEN Cluster for Pioneering Research and RIKEN Center for Advanced ...

Solar cells: Losses made visible on the nanoscale

Solar cells made of crystalline silicon achieve peak efficiencies, especially in combination with selective contacts made of amorphous silicon (a-Si:H). However, their efficiency is limited by losses in these contact layers. ...

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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.

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