China turns on nuclear-powered 'artificial sun' (Update)

China successfully powered up its "artificial sun" nuclear fusion reactor for the first time, state media reported Friday, marking a great advance in the country's nuclear power research capabilities.

New derivation of pi links quantum physics and pure math

In 1655 the English mathematician John Wallis published a book in which he derived a formula for pi as the product of an infinite series of ratios. Now researchers from the University of Rochester, in a surprise discovery, ...

Magnon-based computation could signal computing paradigm shift

Like electronics or photonics, magnonics is an engineering subfield that aims to advance information technologies when it comes to speed, device architecture, and energy consumption. A magnon corresponds to the specific amount ...

Physicist proves impossibility of quantum time crystals

( —Is it possible that a moving object could have zero energy? The common sense answer is no, since motion itself is kinetic energy, but this answer has been challenged recently by the concept of quantum time crystals. ...

Japanese experimental nuclear fusion reactor inaugurated

The world's biggest experimental nuclear fusion reactor in operation was inaugurated in Japan on Friday, a technology in its infancy but billed by some as the answer to humanity's future energy needs.

Theorists solve a long-standing fundamental problem

Trying to understand a system of atoms is like herding gnats - the individual atoms are never at rest and are constantly moving and interacting. When it comes to trying to model the properties and behavior of these kinds ...

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Energy level

A quantum mechanical system or particle that is bound, confined spatially, can only take on certain discrete values of energy, as opposed to classical particles, which can have any energy. These values are called energy levels. The term is most commonly used for the energy levels of electrons in atoms or molecules, which are bound by the electric field of the nucleus. The energy spectrum of a system with energy levels is said to be quantized.

If the potential energy is set to zero at infinity, the usual convention, then bound electron states have negative potential energy.

Energy levels are said to be degenerate, if the same energy level is obtained by more than one quantum mechanical state. They are then called degenerate energy levels.

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