Two-level systems and mass deficit in quantum solids

Abstract

We study a disordered quantum solid incorporating two-level systems in which a group of atoms (or a single atom) can experience coherent tunnelling between two different positions and demonstrate that an effective mass deficit induced by the presence of such objects can manifest itself only at relatively high frequencies and should vanish in the low-frequency limit. The crossover to the regime which can be associated with the appearance of an effective mass deficit has been observed in recent torsional oscillator experiments.

4 pages, LaTeX

References in corpus (5)

• Low Temperature Shear Modulus Changes in Solid 4-He and Connection to Supersolidity
• Disorder and the Supersolid State of Solid ${}^4$He
• Evidence for a Superglass State in Solid 4He
• Observation of non-classical rotational inertia in bulk solid 4He
• On the origin of the decrease in the torsional oscillator period of solid He4

Cited by in corpus (9)

• Evidence for a High-Temperature Disorder-Induced Mobility in Solid ${}^4$He
• A glass anomaly in the shear modulus of solid ${}^4$He
• The glassy response of double torsion oscillators in solid Helium-4
• A search for disordered (glassy) phase in solid 3He deformed in situ
• Shear modulus in viscoelastic solid ${}^4$He
• Tunnelling defect nanoclusters in hcp 4He crystals: alternative to supersolidity
• Defects and glassy dynamics in solid He-4: Perspectives and current status
• BCC vs. HCP - The Effect of Crystal Symmetry on the High Temperature Mobility of Solid ${}^4$He
• The role of glass dynamics in the anomaly of the dielectric function of solid helium