# Low-temperature shear modulus changes in solid 4He and connection to supersolidity

@article{Day2007LowtemperatureSM,
title={Low-temperature shear modulus changes in solid 4He and connection to supersolidity},
author={James Day and John Beamish},
journal={Nature},
year={2007},
volume={450},
pages={853-856}
}
• Published 28 September 2007
• Physics
• Nature
Superfluidity—liquid flow without friction—is familiar in helium. The first evidence for ‘supersolidity’, its analogue in quantum solids, came from torsional oscillator measurements involving 4He. At temperatures below 200 mK, the torsional oscillator frequencies increased, suggesting that some of the solid decoupled from the oscillator. This behaviour has been replicated by several groups, but solid 4He does not respond to pressure differences, and persistent currents and other signatures of…

### Elastic Properties of Solid 4He

The shear modulus of solid 4He increases below 200 mK, with the same dependence on temperature, amplitude and 3He concentration as the frequency changes recently seen in torsional oscillator (TO)

### Elastic properties of solid helium

• Physics
Journal of physics. Condensed matter : an Institute of Physics journal
• 2009
A new technique for measuring the shear modulus of solid helium at low frequencies and small strains is developed and it is clear that the two phenomena are closely related.

### Low frequency shear modulus of bcc 3He below 1 K

• Physics
• 2009
Recent measurements on hcp 4He crystals showed an anomalous stiffening of the shear modulus below 200 mK. This is the temperature range in which torsional oscillator experiments saw evidence of

### Torsional oscillators and the entropy dilemma of putative supersolid 4He

• Physics
• 2009
Solid 4He is viewed as a nearly perfect Debye solid. Yet, recent calorimetry measurements by the PSU group (J. Low Temp. Phys. 138, 853 (2005) and Nature 449, 1025 (2007)) indicate that at low

### Defects and supersolidity: effects of annealing and stress on elastic behavior of solid He4

• Materials Science
• 2008
Recent measurements have shown that solid He4 can decouple from a torsional oscillator below 200mK, and defects appear to be crucial to this behavior. Helium’s shear modulus increases in the same

### Interplay of Rotational, Relaxational, and Shear Dynamics in Solid 4He

• Physics
Science
• 2011
Using a high-sensitivity torsional oscillator (TO) technique, the rotational and relaxational dynamics of solid helium-4 (4He) are mapped throughout the parameter range of the proposed supersolidity and it is demonstrated that the combined temperature-velocity dependence of the TO response is indistinguishable from the combinedTemperature-strain dependence ofThe solid’s shear modulus.

### Evidence for a Superglass State in Solid 4He

• Physics
Science
• 2009
A new theoretical argument and a study of the temperature-dependent relaxation dynamics of helium show that defects may play an important role in describing its supersolid behavior, and provides evidence for a “supersolid glass,” where glassy behavior of crystal dislocations and superfluidity can coexist.

### Anomalous Response of 4He Confined in Nanoporous Media to Torsional Oscillation

• Physics
• 2012
The existence of “Non-Classical Rotational Inertia (NCRI)” in solid 4He below 0.2 K has been controversial and interpreted by a number of different theories. We report on torsional oscillator

### Evidence of Supersolidity in Rotating Solid Helium

• Physics
Science
• 2010
Measurements on rotating frozen helium support the formation of a quantum, or supersolid, phase, and superimposing rotation onto oscillatory measurements may distinguish between supersolidity and classical effects.

### Study of Supersolidity and Shear Modulus Anomaly of 4He in a Triple Compound Oscillator

• Physics
• 2012
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

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