On-demand control of terahertz and infrared waves

The ability to control infrared and terahertz waves using magnetic or electric fields is one of the great challenges in physics that could revolutionise opto-electronics, telecommunications and medical diagnostics. A theory ...

Physicists OK commercial graphene for T-wave detection

Russian researchers from the Moscow Institute of Physics and Technology (MIPT) and Valiev Institute of Physics and Technology have demonstrated resonant absorption of terahertz radiation in commercially available graphene. ...

Mapping the world's largest terrestrial carbon store

A group of researchers have reported how much peatland there is in the world. Peatlands can store carbon (C) and help regulate the climate. But peatland degradation is releasing carbon into the atmosphere. To conserve peatlands ...

Dashing the dream of ideal 'invisibility' cloaks for stress waves

Whether Harry Potter's invisibility cloak, which perfectly steers light waves around objects to make them invisible, will ever become reality remains to be seen, but perfecting a more crucial cloak is impossible, a new study ...

Three ways to travel at (nearly) the speed of light

One hundred years ago today, on May 29, 1919, measurements of a solar eclipse offered verification for Einstein's theory of general relativity. Even before that, Einstein had developed the theory of special relativity, which ...

Natural spectral lines

Certain ranges of frequency across the electromagnetic spectrum are reserved by regulators for particular applications: TV, digital radio, Wi-Fi, Bluetooth etc. Unregulated devices are precluded from broadcasting on these ...

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Electromagnetism

Electromagnetism is one of the four fundamental interactions in nature. The other three are the strong interaction, the weak interaction and gravitation. Electromagnetism is the force that causes the interaction between electrically charged particles; the areas in which this happens are called electromagnetic fields.

Electromagnetism is responsible for practically all the phenomena encountered in daily life, with the exception of gravity. Ordinary matter takes its form as a result of intermolecular forces between individual molecules in matter. Electromagnetism is also the force which attracts electrons to an atomic nucleus to form atoms, which are the building blocks of molecules. This governs the processes involved in chemistry, which arise from interactions between the electrons of neighboring atoms.

Electromagnetism manifests as both electric fields and magnetic fields. Both fields are simply different aspects of electromagnetism, and hence are intrinsically related. Thus, a changing electric field generates a magnetic field; conversely a changing magnetic field generates an electric field. This effect is called electromagnetic induction, and is the basis of operation for electrical generators, induction motors, and transformers. Mathematically speaking, magnetic fields and electric fields are convertible with relative motion as a four vector.

Electric fields are the cause of several common phenomena, such as electric potential (such as the voltage of a battery) and electric current (such as the flow of electricity through a flashlight). Magnetic fields are the cause of the force associated with magnets.

In quantum electrodynamics, electromagnetic interactions between charged particles can be calculated using the method of Feynman diagrams, in which we picture messenger particles called virtual photons being exchanged between charged particles. This method can be derived from the field picture through perturbation theory.

The theoretical implications of electromagnetism led to the development of special relativity by Albert Einstein in 1905.

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