Related papers: Elastic Constants of Incommensurate Solid 4He
The recently discovered shear modulus anomaly in solid 4He bears a strong similarity to the phenomenon of supersolidity in solid 4He and can lead to the period shift and dissipative signals in torsional oscillator experiments that are…
Nonlinear elastic properties of polymers and polymeric composites are essential for accurate prediction of their response to dynamic loads, which is crucial in a wide range of applications. These properties can be affected by strain rate,…
We have re-examined the Andreev-Lifshitz theory of supersolids. This theory implicitly neglects uniform bulk processes that change the vacancy number, and assumes an internal pressure $P$ in addition to lattice stress $\lambda_{ik}$. Each…
Solid 4He has been created off the melting curve by growth at nearly constant mass via the "blocked capillary" technique and growth from the 4He superfluid at constant temperature. The experimental apparatus allows injection of 4He atoms…
The properties of crystals consisting of several components can be widely tuned. Often solid solutions are produced, where substitutional or interstitional disorder determines the crystal thermodynamic and mechanical properties. The…
We report torsional oscillator supersolid studies of highly disordered samples of solid $^4$He. In an attempt to approach the amorphous or glassy state of the solid, we prepare our samples by rapid freezing from the normal phase of liquid…
We have observed a Bose-Einstein Condensate in a dilute gas of $^4$He in the $2^3S_1$ metastable state. We find a critical temperature of $(4.7\pm0.5) \mu$K and a typical number of atoms at the threshold of $8\times10^6$. The maximum number…
We report a numerical calculation of the elastic constants of the fcc and hcp crystal phases of monodisperse hard-sphere colloids. Surprisingly, some of these elastic constants are very different (up to 20%), even though the free energy,…
Starting from a model of 4f-electron generated quadrupolar densities on a compressible fcc lattice, the elastic anomalies at the Fm3m -> Pa3 phase transition are studied by means of analytical theory. The model is taken as representative…
A new microscopic derivation of the elastic constants of amorphous solids is presented within the framework of nonaffine lattice dynamics, which makes use of a perturbative form of the low-frequency eigenvectors of the dynamical matrix…
We have measured the melting pressure and pressure in the liquid at constant density of ultra-pure $^4$He (0.3 ppb of $^3$He impurities) with the accuracy of about 0.5 $\mu$bar in the temperature range from 10 to 320 mK. Our measurements…
We combine density functional theory within the local density approximation, the quasiharmonic approximation, and vibrational density of states to calculate single crystal elastic constants, and bulk and shear moduli of diamond at…
Using molecular dynamics simulations we compute the elastic constants of ice I$_h$ for a set of 8 frequently used semi-empirical potentials for water, namely the rigid-molecule SPC/E, TIP4P, TIP4P2005, TIP4P/Ice and TIP5P models, the…
We present a theoretical study of the excitations of the two-dimensional supersolid state of a Bose-Einstein condensate with either dipole-dipole interactions or soft-core interactions. This supersolid state has three gapless excitation…
We developed a detailed microscopic method that describes the shear modulus anomaly of solid helium at low temperature. The shear modulus was calculated using the pinning length of dislocations determined in detail for both crossing network…
We made heat-capacity measurements of two dimensional (2D) $^3$He adsorbed on graphite preplated with monolayer $^4$He in a wide temperature range (0.1 $\leq T \leq$ 80 mK) at densities higher than that for the 4/7 phase (= 6.8 nm$^{-2}$).…
The effect of finite temperature $T$ and finite strain rate $\dot\gamma$ on the statistical physics of plastic deformations in amorphous solids made of $N$ particles is investigated. We recognize three regimes of temperature where the…
We report a study of the temperature and stress dependence of the friction associated with a relative motion of two masses of solid $^4$He in contact. The situation where "two masses" coupled only by friction exists emerges spontaneously…
In the paper, the thermodynamic parameters of the high-pressure superconducting state in the SiH$_4$ compound have been determined ($p=250$ GPa). By using the Eliashberg equations in the mixed representation, the critical temperature, the…
We have confirmed the existence, as first reported by Kim and Chan, of a supersolid state in solid 4He at temperatures below 250 mK. We have employed a torsional oscillator cell with a square cross section to insure a locking of the solid…