Related topics: physical review letters

A new view for glasses

Researchers at the University of Tokyo introduced a new physical model that predicts the dynamics of glassy materials based solely on their local degree of atomic structural order. Using computer simulations, they showed ...

A four-way switch promises greater tunability of layered materials

A scientific team from the Department of Energy's Oak Ridge National Laboratory and Vanderbilt University has made the first experimental observation of a material phase that had been predicted but never seen. The newly discovered ...

Peering into batteries: X-rays reveal lithium-ion's mysteries

Billions of smartphone owners are familiar with the dreaded "low battery" symbol on their devices. While consumers groan, scientists are working to understand why and when lithium-ion batteries in phones, plug-in electric ...

Quantum destabilization of a water sandwich

From raindrops rolling off the waxy surface of a waterlily leaf to the efficiency of desalination membranes, interactions between water molecules and water-repellent "hydrophobic" surfaces are all around us. The interplay ...

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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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