TY - JOUR
T1 - Nuclear-spin noise and spontaneous emission
AU - Sleator, Tycho
AU - Hahn, Erwin L.
AU - Hilbert, Claude
AU - Clarke, John
PY - 1987
Y1 - 1987
N2 - The spontaneous emission from nuclear spins has been observed at liquid-4He temperatures. The spins, Cl35 nuclei, are placed in the inductor of a tuned LCR circuit coupled to a dc superconducting quantum interference device used as a radio-frequency amplifier. When the spins are saturated and have zero polarization, the emission is observed at the nuclear quadrupole Larmor frequency as a bump in the spectral density of the Nyquist noise current in the tuned circuit. This bump arises from the temperature-independent fluctuations in the transverse component of the nuclear magnetization. When the spins are in thermal equilibrium, on the other hand, a dip in the spectral density of the current noise is observed, arising from an induced absorption of noise power from the circuit at the Larmor frequency. The standard circuit-coupled Blochs equation, modified to take into account radiation damping and transverse spin fluctuations, is consistent with the predictions of the Nyquist theorem and the Einstein equation for spontaneous emission. A spin-pendulum model for spin noise is described. The signal-to-noise ratio obtainable in a spin-noise measurement is discussed.
AB - The spontaneous emission from nuclear spins has been observed at liquid-4He temperatures. The spins, Cl35 nuclei, are placed in the inductor of a tuned LCR circuit coupled to a dc superconducting quantum interference device used as a radio-frequency amplifier. When the spins are saturated and have zero polarization, the emission is observed at the nuclear quadrupole Larmor frequency as a bump in the spectral density of the Nyquist noise current in the tuned circuit. This bump arises from the temperature-independent fluctuations in the transverse component of the nuclear magnetization. When the spins are in thermal equilibrium, on the other hand, a dip in the spectral density of the current noise is observed, arising from an induced absorption of noise power from the circuit at the Larmor frequency. The standard circuit-coupled Blochs equation, modified to take into account radiation damping and transverse spin fluctuations, is consistent with the predictions of the Nyquist theorem and the Einstein equation for spontaneous emission. A spin-pendulum model for spin noise is described. The signal-to-noise ratio obtainable in a spin-noise measurement is discussed.
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U2 - 10.1103/PhysRevB.36.1969
DO - 10.1103/PhysRevB.36.1969
M3 - Article
AN - SCOPUS:0000077153
SN - 0163-1829
VL - 36
SP - 1969
EP - 1980
JO - Physical Review B
JF - Physical Review B
IS - 4
ER -