Mass Flow through Solid <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>He</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math> in the bcc Phase
Bibliographic record
Abstract
A number of experiments have shown that mass can be transported through solid ^{4}He at temperatures as low as 16 mK, with features that suggest superflow. But the nature of this flow remains unclear. The Fermi isotope ^{3}He provides the possibility of a direct comparison to a solid in which quantum effects are even more important but superfluidity is not expected. We have made flow measurements on high purity bcc ^{3}He, using the same cell in which we observed a superfluidlike response in hcp ^{4}He when pressure differences were applied. We observed flow but, in marked contrast to ^{4}He, it decreased monotonically with temperature. Near melting, the flow was thermally activated with an energy of 0.85 K, but some flow remained even at 30 mK. The flow rates in the solid were essentially constant below 100 mK, even in low density samples that remelted at low temperatures. The very different behaviors of solid ^{3}He and ^{4}He support the interpretation of superflow in ^{4}He. Although such superflow is not possible in ^{3}He, the temperature-independent flow below 100 mK indicates that the flow in this regime also has a quantum origin. The flow must involve defects and, based on the magnitude of the flow and comparisons to other experiments, we conclude that in both the thermal and the quantum regimes the flow involves motion of dislocations via thermally activated or tunneling motion of kinks.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.009 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".