Muon depolarization in liquid3He

We report the first measurements of the positive-muon spin depolarization in liquid³He. The relaxation of the muon and muonium precession has been studied in transverse, longitudinal, and zero magnetic fields in the temperature range 0.5–2.5 K. The results are discussed in terms of two different depolarization mechanisms: recombinational depolarization (i.e. slow muonium formation) and magnetic relaxation due to the³He nuclear magnetic moments.     

Phase transitions in liquid 3He

The phase transitions of liquid 3He are described by truncations of an exact nonperturbative renormalization group equation. The location of the first-order transition lines and the jump in the order parameter are computed quantitatively. At the triple point we find indications of partially universal behavior. We suggest experiments that could help to determine the effective interactions between fermion pairs.     

Anomaly in the stability limit of liquid 3He

We propose that the liquid-gas spinodal line of 3He reaches a minimum at 0.4 K. This feature is supported by our cavitation measurements. We also show that it is consistent with extrapolations of sound-velocity measurements. Speedy [J. Phys. Chem. 86, 3002 (1982)] previously proposed this peculiar behavior for the spinodal of water and related it to a change in sign of the expansion coefficient alpha, i.e., a line of density maxima. 3He exhibits such a line at positive pressure. We consider its extrapolation to negative pressure. Our discussion raises fundamental questions about the sign of alpha in a Fermi liquid along its spinodal.     

High-momentum response of liquid 3He

A final-state-effects formalism suitable to analyze the high-momentum response of Fermi liquids is presented and used to study the dynamic structure function of liquid 3He. The theory, developed as a natural extension of the Gersch-Rodriguez formalism, incorporates the Fermi statistics explicitly through a new additive term which depends on the semidiagonal two-body density matrix. The use of a realistic momentum distribution, calculated using the diffusion Monte Carlo method, and the inclusion of this additive correction allows for good agreement with available deep-inelastic neutron scattering data.     

Damping of zero sound in liquid3He

The dynamic structure factor in liquid³He is calculated within the framework of Dissipative Linear Response (DLR) equations. The effective interaction is represented by the Landau parameters up tol=2 and the Random Phase Approximation (RPA)-scattering amplitudes are evaluated in thes–p–d approximation. The dissipative linear response operator is calculated on the basis of RPA solutions of undamped zero sound using integral equation techniques.The dynamical structure factor has a strong resonance structure whose width agrees with measurements of the attenuation coefficient for small momentum transfers. At larger values of momentum transfer, where the dynamical structure factor has been directly measured, the Landau parameters do not give more than a qualitative agreement with the data.     

Dynamic structure function of liquid 3He

The dynamic structure function S(Q, ω) of liquid ³He is evaluated in the impulse approximation, based on a theoretically calculated momentum distribution n(k). The gap of n(k) at the Fermi surface gives rise to discontinuities in the slope of S(Q = const., ω) which may be detectable in neutron- or γ-ray scattering experiments.     

Thermal conductivity of spin-polarized liquid 3He

We present the first measurements of the thermal conductivity of spin-polarized normal liquid 3He. Using the rapid melting technique to produce nuclear polarizations up to 0.7, and a vibrating wire both as a heater and a thermometer, we show that, unlike the viscosity, the conductivity increases much less than predicted for s-wave scattering. We suggest that this might be due to a small probability for head-on collisions between quasiparticles.     

Polarization decreases the specific heat of liquid 3He

We report on the first measurements of the polarization dependence of the specific heat of liquid 3He. Transient polarizations m of up to 70% were reached by using the rapid melting technique. The specific heat at 60-100 mK and 27 bars is found to decrease approximately as m(2), the reduction reaching at least 30% for m = 70%. These results contradict the nearly localized picture of 3He, and are in agreement with the idea that a large part of the specific heat is due to spin fluctuations.     

Zero sound mode in normal liquid 3He

Inelastic x-ray scattering has been utilized to study the elementary excitations of normal liquid 3He at the temperature T=1.10+/-0.05 K and saturated vapor pressure in the wave vector range 0.15相似文献   

Low-temperature spin-relaxation time in normal liquid 3He

We calculate the low-temperature (T ? T_F) spin-relaxation time T₁ in normal liquid ³He, expressed in terms of the perturbations of the scattering amplitudes due to nuclear dipole-dipole interactions. These perturbations are obtained using the induced interaction model, yielding good agreement with experiment, as well as with previous calculations.     

Anomalous positive ion mobility in liquid 3He

Measurements of the mobility μ₊ of positive ions in liquid ³He under a pressure of 1 bar in the temperature range 0.05 < T < 0.6K exhibit a sharp peak in μ₊(T) near 0.2K and irreproducible behaviour at lower temperatures.