Probing phase coherence in solid helium using torsional oscillators of different path lengths

Kim, Duk Y.; West, Joshua T.; Engstrom, Tyler; Mulders, N.; Chan, Moses H. W.

doi:10.1103/physrevb.85.024533

Cited by 13 publications

(18 citation statements)

References 32 publications

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“…For our open cylindrical cell we get a reduction in the sensitivity of about a factor of two compared with the case of a single-mode oscillator. Even with that reduction, our sensitivity to changes in the moment of inertia of the helium is around Δp F =p = 0.01, comparable to the numbers reported by the Chan group for their high-sensitivity long-path-length experiments (35).…”

Section: Significancesupporting

confidence: 84%

Search for supersolidity in solid ⁴ He using multiple-mode torsional oscillators

Eyal

Talanov

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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In 2004, Kim and Chan (KC) reported a decrease in the period of torsional oscillators (TO) containing samples of solid 4 He, as the temperature was lowered below 0.2 K Science 305(5692) :1941-1944]. These unexpected results constituted the first experimental evidence that the long-predicted supersolid state of solid 4 He may exist in nature. The KC results were quickly confirmed in a number of other laboratories and created great excitement in the low-temperature condensed-matter community. Since that time, however, it has become clear that the period shifts seen in the early experiments can in large part be explained by an increase in the shear modulus of the 4 He solid identified by Day and Beamish [Day J, Beamish J (2007) Nature 450(7171):853-856]. Using multiple-frequency torsional oscillators, we can separate frequency-dependent period shifts arising from changes in the elastic properties of the solid 4 He from possible supersolid signals, which are expected to be independent of frequency. We find in our measurements that as the temperature is lowered below 0.2 K, a clear frequency-dependent contribution to the period shift arising from changes in the 4 He elastic properties is always present. For all of the cells reported in this paper, however, there is always an additional small frequency-independent contribution to the total period shift, such as would be expected in the case of a transition to a supersolid state.supersolid | helium 4 | torsional oscillators T he idea of the existence of a supersolid state, a new phase of matter, stimulated a large number of experimental and theoretical works over the past 45 y, especially in the past decade. Such a state is assumed to present properties of superflow in a, most likely bosonic, solid. It was first suggested to exist based on theoretical grounds by Andreev and Lifshitz (1), Chester (2), and Leggett (3) in the late 1960s and early 1970s. Because 4 He exhibits superfluidity, and because it is a bosonic material with a low mass and weak interatomic interactions, solid 4 He was a natural candidate in the search for supersolidity.Torsional oscillators (TOs) have been the chief instrument in the investigation of this possible supersolid state of 4 He. The use of TOs in the search for this state follows a suggestion by Leggett in 1970 (3) that the appearance of the supersolid state would result in an anomalous superfluid-like decoupling of a portion of the moment of inertia of the solid 4 He sample from the TO in a manner analogous to the decoupling of the superfluid fraction of liquid 4 He as observed by Andronikashvili (4) in his early TO experiments. Such a reduction of the moment of inertia upon entering the superfluid or supersolid state was termed by Leggett to be a nonclassical rotational inertia (NCRI). The NCRI reduction in the moment of inertia is then expected to begin to increase with decreasing temperature below an onset temperature and lead to an observable decrease in the period of a TO containing a supersolid sample.The first attempt to observe ...

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Section: Significancesupporting

confidence: 84%

Search for supersolidity in solid ⁴ He using multiple-mode torsional oscillators

Eyal

Talanov

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Another important development in the investigation of magnetism in quasicrystals was the discovery of AFM order in the R Cd 6 cubic approximants, first indicated by bulk magnetization measurements [47, 49, 50] and established to be long-range AFM order by x-ray resonant magnetic scattering (XRMS) measurements at the Tb x-ray absorption edge of a single crystal [48]. Figure 11 shows the magnetic susceptibility of which exhibits anomalies at = 24 K, = 19 K and = 2.4 K [47].…”

Section: Binary Magnetic Icosahedral Quasicrystals and Approximants Imentioning

confidence: 99%

“…The XRMS measurements on [48] and [51] clearly demonstrated that long-range AFM order is established in these approximants below 24 K and 8.5 K, respectively. Shown in figure 12 are scans through the charge peak and magnetic peak positions showing that sharp Bragg peaks are observed for the magnetic scattering from with a magnetic correlation length greater than 500 Å.…”

Section: Binary Magnetic Icosahedral Quasicrystals and Approximants Imentioning

confidence: 99%

Magnetism in icosahedral quasicrystals: current status and open questions

Goldman

2014

Science and Technology of Advanced Materials

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Progress in our understanding of the magnetic properties of R-containing icosahedral quasicrystals (R = rare earth element) from over 20 years of experimental effort is reviewed. This includes the much studied R-Mg-Zn and R-Mg-Cd ternary systems, as well as several magnetic quasicrystals that have been discovered and investigated more recently including Sc-Fe-Zn, R-Ag-In, Yb-Au-Al, the recently synthesized R-Cd binary quasicrystals, and their periodic approximants. In many ways, the magnetic properties among these quasicrystals are very similar. However, differences are observed that suggest new experiments and promising directions for future research.

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“…In some TOs, solid helium contributes significantly to the mechanical coupling of the different parts of the torsion cell. The coupling is strengthened when the solid helium sample is stiffened at low temperature resulting in a lower resonant period [4,17]. The torsion rod is usually attached at the center of one end of the (cylindrical) torsion cell.…”

mentioning

confidence: 99%

Absence of Supersolidity in Solid Helium in Porous Vycor Glass

2012

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In 2004, Kim and Chan (KC) carried out torsional oscillator (TO) measurements of solid helium confined in porous Vycor glass and found an abrupt drop in the resonant period below 200 mK. The period drop was interpreted as probable experimental evidence of nonclassical rotational inertia (NCRI). This experiment sparked considerable activities in the studies of superfluidity in solid helium. More recent ultrasound and TO studies, however, found evidence that shear modulus stiffening is responsible for at least a fraction of the period drop found in bulk solid helium samples. The experimental configuration of KC makes it unavoidable to have a small amount of bulk solid inside the torsion cell containing the Vycor disc. We report here the results of a new helium in Vycor experiment with a design that is completely free from any bulk solid shear modulus stiffening effect. We found no measureable period drop that can be attributed to NCRI.

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Probing phase coherence in solid helium using torsional oscillators of different path lengths

Cited by 13 publications

References 32 publications

Search for supersolidity in solid ⁴ He using multiple-mode torsional oscillators

Search for supersolidity in solid ⁴ He using multiple-mode torsional oscillators

Magnetism in icosahedral quasicrystals: current status and open questions

Absence of Supersolidity in Solid Helium in Porous Vycor Glass

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Probing phase coherence in solid helium using torsional oscillators of different path lengths

Cited by 13 publications

References 32 publications

Search for supersolidity in solid 4 He using multiple-mode torsional oscillators

Search for supersolidity in solid 4 He using multiple-mode torsional oscillators

Magnetism in icosahedral quasicrystals: current status and open questions

Absence of Supersolidity in Solid Helium in Porous Vycor Glass

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Search for supersolidity in solid ⁴ He using multiple-mode torsional oscillators

Search for supersolidity in solid ⁴ He using multiple-mode torsional oscillators