Effect of dipole interaction on collective modes in /sup 3/He-A

Journal Article · Sat Oct 01 04:00:00 EDT 1977 · J. Low Temp. Phys.; (United States)

DOI:https://doi.org/10.1007/BF00659092· OSTI ID:5350852

Tewordt, L; Schopohl, N; Vollhardt, D

A general theory for the correlation functions of superfluid /sup 3/He which takes into account rigorously the magnetic dipole interaction is developed. The resulting equations are solved for the Anderson--Brinkman--Morel (ABM) state and for wave vectors q oriented parallel to the energy gap axis. Then the dispersion relations of low-frequency modes, including Fermi liquid corrections and damping due to pair breaking, are calculated in the zero-temperature and zero-field limit. There are two real frequency modes arising from each of the longitudinal and transverse spin density correlation functions: a spin wave and an orbit wave, both exhibiting a frequency gap where that of the spin wave is somewhat modified in comparison to the unperturbed longitudinal nuclear magnetic resonance frequency ..cap omega../sup ABM//sub L/. The orbit wave is damped much more strongly than the spin wave. Further, there are two real frequency modes arising from the density correlation function: the sound wave, having a frequency gap of the order ..cap omega../sup ABM//sub L/, and an orbit wave, exhibiting a gap in wave number of order ..cap omega../sup ABM//sub L//v/sub F/.: The NMR frequency undergoes a small splitting, which is the result of the splitting of the energy gap due to the dipole interaction. One of the two gaps still has nodes.: In addition to these low-frequency modes our equations yield resonances at frequencies of the order of the gap frequency ..delta../sub 0//h, i.e., at ..omega..=1.22..delta../sub 0//h and at ..omega..=1.58 ..delta../sub 0//h. The damping and the oscillator strengths of these resonances are calculated.

• Research Organization: Abteilung fuer Theoretische Festikoerperphysik, Universitaet Hamburg, Hamburg, Germany
• OSTI ID: 5350852
• Journal Information: J. Low Temp. Phys.; (United States), Journal Name: J. Low Temp. Phys.; (United States) Vol. 29:1/2; ISSN JLTPA
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COLLECTIVE EXCITATIONS
DAMPING
DIPOLE MOMENTS
DISPERSION RELATIONS
ENERGY GAP
EVEN-ODD NUCLEI
HELIUM 3
HELIUM 3 A
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAGNETIC DIPOLE MOMENTS
MAGNETIC MOMENTS
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
OSCILLATOR STRENGTHS
RESONANCE
SPIN WAVES
STABLE ISOTOPES
SUPERFLUIDITY