Related topics: physical review letters

Supercomputing simulations spot electron orbital signatures

No one will ever be able to see a purely mathematical construct such as a perfect sphere. But now, scientists using supercomputer simulations and atomic resolution microscopes have imaged the signatures of electron orbitals, ...

Visualizing PET's degradation by bacterial enzymes

The rigidity, transparency and hardness of PET (Polyethylene Terephthalate) make it one of the most valuable plastics for the manufacture of plastic bottles, packaging and other single-use products. However, these characteristics ...

How the ancient messengers cAMP and cGMP deliver their messages

Two highly similar molecules with essential but often contrasting signaling roles in most life forms exert their distinct effects through subtle differences in their bindings to their signaling partners, according to a new ...

Ibogaine inspires new compounds to treat addiction, depression

Scientists have developed two new drug candidates for potentially treating addiction and depression, modeled on the pharmacology of a traditional African psychedelic plant medicine called ibogaine. At very low doses, these ...

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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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