Distinguishing between right and left with magnets

Using a chiral superconductor, scientists at Institute for Molecular Science and Shizuoka University have demonstrated that the magnet can distinguish right and left forms of the chiral crystal despite the common belief that ...

An enhanced cooling method for the quantum world

The quantum nature of objects visible to the naked eye is currently a much-discussed research question. A team led by Innsbruck physicist Gerhard Kirchmair has now demonstrated a new method in the laboratory that could make ...

Lab develops new method for on-chip generation of single photon

As buzz grows ever louder over the future of quantum, researchers everywhere are working overtime to discover how best to unlock the promise of super-positioned, entangled, tunneling or otherwise ready-for-primetime quantum ...

Nobel-winning Swiss physicist Muller dies at 95

Swiss physicist Karl Alex Muller, who won the Nobel Physics Prize in 1987 along with his German colleague Georg Bednorz for their discovery of the first high-temperature superconductor, has died.

A new qubit approach for more stable states for quantum computers

Quantum computers can more rapidly process large amounts of data, because they carry out many computation steps in parallel. The information carrier of the quantum computer is a qubit. Qubits do not only possess the information ...

Optomechanics simulates graphene lattices

The precise control of micro-mechanical oscillators is fundamental to many contemporary technologies, from sensing and timing to radiofrequency filters in smartphones. Over the past decade, quantum control of mechanical systems ...

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Superconductivity is a phenomenon occurring in certain materials generally at very low temperatures, characterized by exactly zero electrical resistance and the exclusion of the interior magnetic field (the Meissner effect). It was discovered by Heike Kamerlingh Onnes in 1911. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon. It cannot be understood simply as the idealization of "perfect conductivity" in classical physics.

The electrical resistivity of a metallic conductor decreases gradually as the temperature is lowered. However, in ordinary conductors such as copper and silver, impurities and other defects impose a lower limit. Even near absolute zero a real sample of copper shows a non-zero resistance. The resistance of a superconductor, despite these imperfections, drops abruptly to zero when the material is cooled below its "critical temperature". An electric current flowing in a loop of superconducting wire can persist indefinitely with no power source.

Superconductivity occurs in a wide variety of materials, including simple elements like tin and aluminium, various metallic alloys and some heavily-doped semiconductors. Superconductivity does not occur in noble metals like gold and silver, nor in pure samples of ferromagnetic metals.

In 1986 the discovery of a family of cuprate-perovskite ceramic materials known as high-temperature superconductors, with critical temperatures in excess of 90 kelvin, spurred renewed interest and research in superconductivity for several reasons. As a topic of pure research, these materials represented a new phenomenon not explained by the current theory. In addition, because the superconducting state persists up to more manageable temperatures, past the economically-important boiling point of liquid nitrogen (77 kelvin), more commercial applications are feasible, especially if materials with even higher critical temperatures could be discovered.

See also the history of superconductivity.

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