Magnetic resonance is a process by which a physical

excitation Excitation, excite, exciting, or excitement may refer to: * Excitation (magnetic), provided with an electrical generator or alternator * ''Exite'', a series of racing video games published by Nintendo starting with ''Excitebike'' * Excite (web port ...

(

resonance Resonance is a phenomenon that occurs when an object or system is subjected to an external force or vibration whose frequency matches a resonant frequency (or resonance frequency) of the system, defined as a frequency that generates a maximu ...

) is set up via

magnetism Magnetism is the class of physical attributes that occur through a magnetic field, which allows objects to attract or repel each other. Because both electric currents and magnetic moments of elementary particles give rise to a magnetic field, ...

. This process was used to develop

magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ...

(MRI) and

nuclear magnetic resonance spectroscopy Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a Spectroscopy, spectroscopic technique based on re-orientation of Atomic nucleus, atomic nuclei with non-zero nuclear sp ...

(NMRS) technology. It is also being used to develop

nuclear magnetic resonance quantum computer Nuclear magnetic resonance quantum computing (NMRQC) is one of the several proposed approaches for constructing a quantum computer, that uses the spin states of nuclei within molecules as qubits. The quantum states are probed through the nuclear m ...

History

The first observation of electron-spin resonance was in 1944 by Y. K. Zavosky, a Soviet physicist then teaching at

Kazan State University Kazan Federal University (; ) is a public research university located in Kazan, Russia. The university was founded in 1804 as Imperial Kazan University, which makes it the second oldest continuously existing tertiary education institution in Rus ...

(now Kazan Federal University). Nuclear magnetic resonance was first observed in 1946 in the US by a team led by

Felix Bloch Felix Bloch (; ; 23 October 1905 – 10 September 1983) was a Swiss-American physicist who shared the 1952 Nobel Prize in Physics with Edward Mills Purcell "for their development of new methods for nuclear magnetic precision measurements and di ...

at the same time as a separate team led by

Edward Mills Purcell Edward Mills Purcell (August 30, 1912 – March 7, 1997) was an American physicist who shared the 1952 Nobel Prize for Physics for his independent discovery (published 1946) of nuclear magnetic resonance in liquids and in solids. Nuclear magn ...

, the two of whom would later be the 1952 Nobel Laureates in Physics.

Resonant and non-resonant methods

A natural way to measure the separation between two energy levels is to find a measurable quantity defined by this separation and measure it. However, the precision of this method is limited by measurement precision and thus may be poor. Alternatively, we can set up an experiment in which the system's behavior depends on the energy level. If we apply an external field of controlled frequency, we can measure the level separation by noting at which frequency a qualitative change happens: that would mean that at this frequency, the transition between two states has a high probability. An example of such an experiment is a variation of

Stern–Gerlach experiment In quantum physics, the Stern–Gerlach experiment demonstrated that the spatial orientation of angular momentum is quantization (physics), quantized. Thus an Atomic spacing, atomic-scale system was shown to have intrinsically quantum propertie ...

, in which magnetic moment is measured by finding resonance frequency for the transition between two spin states.

References

Magnetic resonance imaging Magnetism Physical phenomena {{MRI-stub

History

Resonant and non-resonant methods

See also

References