Much more work remains to be done in this extremely active area of current research. Samples at temperatures above 600 mK have never shown flow in any Colder temperatures result in flow higher temepratueresĪt nearly the same pressure do not. Movement of the pressures towards equilibrium. R1 for about 30 minutes, but over 7 hours there was no significant In this case the regulator fed atoms into So, if this is the case there must beĪ transition in properties in the solid that depends on pressure and temperature.įigure 3: An example of a sample of solid helium that did not show flow.įrom 400 to 547 mK (from sample BS). Result in the movement of atoms through the solid. Some regions of the solid helium phase diagram do not seem to The physical mechanism by which this takes place has The data in figure #2 and other data like it demonstrate that it isĪpparently possible to transfer atoms through solid
Of the solid helium in the cell is also recorded on the in situ pressure gauge C1. Nearly linear for a substantial duration and independent of P1-P2. Pressure were observed for about 6 hours. To line 1 was closed at t $\approx$ 30 minutes, and changes in Increased at t $\approx$ 6 minutes, the regulator feeding helium Though the solid helium from line #1 to line #2.įigure 2: An example of a sample of solid helium (Sample BS ref 6) showing a flow Thus, any change in the pressure in line #2 indicates that mass moved Migrate through the experimental cell, which Observed on the other fill line or the cell implies that atoms had to #1, and looks for a response on the other fill line, #2. The principle of operation of the appartus is rather simple. Vycor and was used to initially fill the cell with liquid helium, which was then frozen. Third capillary, 3, was heat sunk in several places including the Pressure transducers P1 and P2 located outside of the cryostat. The pressures of the fill lines are measured by Pressure of solid, while the temperature is measured by carbon TwoĬapacitance strain gages, one on each side of S measure the The reservoirs are heated by heaters H1 and H2. Which first lead to liquid reservoirs atop thin porous glass (Vycor) rods V1 and Helium is admitted to the solidĬhamber S through capillaries 1 and 2 (heat-sunk only at 4 K) Figure 1 is a schematicįigure 1: Cell used to study the growth of solid To inject helium atoms into the solid that was in contact with the Thus, by pressurizing the liquid in the porous glass we could attempt In porous glass the freezing pressure of solid helium is Of our apparatus that was filled with solid helium. We created an enviromnent in which porous glass pennetrated the region Typically this is not possible beacuse superfuid heliumin direct contact with the solid would causeĪ hopelessly large heat flux to the sample cell. Solid helium directly (if you squeeze a porous rock, no water will come out even though the water mayįill all the open and connected pores of the rock), we decided to try to inject atoms from the We decided to try to look for flow through helium by a concptiually differentĪpproach. Squeezing on it directly have shown that it is impossible to create flow by this technique. Laboratories, attemps to make the solid flow by Solid helium might be acting like a "supersolid", as state of matter that had beenĪlthough this unusual observation has been confirmed in a number of
Of the solid helium appeared to be left behind by the rotation. Experiments with Solid Helium Solid Helium: Searching for FlowĪ few years ago it was observed that if a container filled with solid helium was rotated, some