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Impurity scattering in superfluid he...

Baumgardner, James Edward, II.

Impurity scattering in superfluid helium-3: A new phase.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Impurity scattering in superfluid helium-3: A new phase.
Author:	Baumgardner, James Edward, II.
Description:	194 p.
Notes:	Adviser: Douglas D. Osheroff.
Notes:	Source: Dissertation Abstracts International, Volume: 65-11, Section: B, page: 5787.
Contained By:	Dissertation Abstracts International65-11B.
Subject:	Physics, Condensed Matter.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3153091
ISBN:	9780496135370

Impurity scattering in superfluid helium-3: A new phase.
Baumgardner, James Edward, II.

Impurity scattering in superfluid helium-3: A new phase. - 194 p.

Adviser: Douglas D. Osheroff.

Thesis (Ph.D.)--Stanford University, 2005.

Having thus established the initial temperatures of the A-B transition on warming and cooling, TAB,w and TAB,c respectively, we consider the value of the equilibrium thermodynamic transition temperature, TAB. We develop a method for determining this temperature from precise measurements of the maximum frequency shifts and susceptibilities of the A-like and B phases. We find that TAB is equal to TAB,w within experimental error for both samples at all pressures where this measurement is possible. On this basis, we present the first thermodynamic A-B phase diagram of superfluid 3He in aerogel. We find that this phase diagram is substantially modified from the bulk, in a manner that is density-independent. We show that for any equal spin pairing state with transverse frequency shifts that agree with the measured value of our A-like phases, the order parameter is uniquely determined from the slope of the equilibrium A-B phase diagram. We tentatively identify the A-like phase as being the planar (two-dimensional) state, which has never before been reported to exist.

ISBN: 9780496135370Subjects--Topical Terms:

226939
Physics, Condensed Matter.

Impurity scattering in superfluid helium-3: A new phase.
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245 1 0 $a Impurity scattering in superfluid helium-3: A new phase.
300 $a 194 p.
500 $a Adviser: Douglas D. Osheroff.
500 $a Source: Dissertation Abstracts International, Volume: 65-11, Section: B, page: 5787.
502 $a Thesis (Ph.D.)--Stanford University, 2005.
520 # $a Having thus established the initial temperatures of the A-B transition on warming and cooling, TAB,w and TAB,c respectively, we consider the value of the equilibrium thermodynamic transition temperature, TAB. We develop a method for determining this temperature from precise measurements of the maximum frequency shifts and susceptibilities of the A-like and B phases. We find that TAB is equal to TAB,w within experimental error for both samples at all pressures where this measurement is possible. On this basis, we present the first thermodynamic A-B phase diagram of superfluid 3He in aerogel. We find that this phase diagram is substantially modified from the bulk, in a manner that is density-independent. We show that for any equal spin pairing state with transverse frequency shifts that agree with the measured value of our A-like phases, the order parameter is uniquely determined from the slope of the equilibrium A-B phase diagram. We tentatively identify the A-like phase as being the planar (two-dimensional) state, which has never before been reported to exist.
520 # $a We present continuous-wave NMR measurements of superfluid 3He confined to two low-density silica aerogels, with porosities of 99.3% and 98.6%. we find a first-order transition on cooling between two superfluid phases, from an A-like equal-spin pairing phase to a B phase. Careful measurements of the NMR spectra, integrated susceptibility, and average frequency shift demonstrate a broadened first-order transition on warming, from the B phase to possibly another A-like equal-spin pairing phase. This A-B transition on warming occurs over a broad range of temperatures, and in both samples, it is unable to convert the entire sample from the B to A-like phase before reaching Tc,aero By performing "trajectory" measurements (warming from the B phase until the A-like phase is seen, then subsequently cooling), we are able to show that the A-like phases on warming and cooling are identical. Measurements of the gap suppression in the A-like phase show that the aerogel has a single value of Tc, so that the width of the A-B transition is caused not by inhomogeneous broadening of the superfluid transition, but rather by pinning of the A-B interface.
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710 0 # $a Stanford University. $3 212607
773 0 # $g 65-11B. $t Dissertation Abstracts International
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790 1 0 $a Osheroff, Douglas D., $e advisor
791 $a Ph.D.
792 $a 2005
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