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Harter, Alexa W.; Lee, Richard A.; Chatto, Andrew; Wu, Xinkai; Chui, Talso; Goodstein, David L.

doi:10.1103/physrevlett.84.2195

Cited by 24 publications

(8 citation statements)

References 17 publications

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“…It has been observed already in our previous paper [14], where C Q has be calculated for the much higher heat current Q = 42.9 µW/cm 2 where gravity effects are negligible. The strong enhancement of the maximum is also compatible with experimental measurements of C Q by Harter et al [25].…”

Section: E Specific Heatsupporting

confidence: 91%

Renormalization-group calculation of the superfluid/normal-fluid interface of liquid4He in gravity nearTλ

Haussmann

2012

Phys. Rev. B

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The superfluid/normal-fluid interface of liquid 4 He is investigated in gravity on earth where a small heat current Q flows vertically upward or downward. We present a local space-and time-dependent renormalization-group (RG) calculation based on model F which describes the dynamic critical effects for temperatures T near the superfluid transition T λ . The model-F equations are rewritten in a dimensionless renormalized form and solved numerically as partial differential equations. Perturbative corrections are included for the spatially inhomogeneous system within a self-consistent one-loop approximation. The RG flow parameter is determined locally as a function of space and time by a constraint equation which is solved by a Newton iteration. As a result we obtain the temperature profile of the interface. Furthermore we calculate the average order parameter ψ , the correlation length ξ, the specific heat CQ and the thermal resistivity ρT where we observe a rounding of the critical singularity by the gravity and the heat current. We compare the thermal resistivity with an experiment and find good qualitative agreement. Moreover we discuss our previous approach for larger heat currents and the self-organized critical state and show that our theory agrees with recent experiments in this latter regime.

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Section: E Specific Heatsupporting

confidence: 91%

Renormalization-group calculation of the superfluid/normal-fluid interface of liquid4He in gravity nearTλ

Haussmann

2012

Phys. Rev. B

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“…In traditional helium under a heat flux, there is predicted a contribution to the heat capacity from the kinetic energy of the flow of the superfluid [10], which has been observed experimentally in a "heat-from-below" configuration [11]. However, it is unclear whether this mechanism would apply to C ∇T , since it is not known how to apply the two-fluid model to the SOC state.…”

Section: The Soc Heat Capacitymentioning

confidence: 99%

Experiments on the Self-Organized Critical State of 4He

Chatto

Lee

Duncan³

et al. 2007

J Low Temp Phys

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AcknowledgementsThere are a number of people I would like to thank for their contributions to this thesis. My advisor David Goodstein was insightful, encouraging, and patient throughout the many challenges of performing a low-temperature experiment. Our conversations were always helpful because David has an extraordinary ability to make complicated concepts seem simple and intuitive. I had two mentors in the lab, Peter Day and Richard Lee, who taught me everything I know about performing experiments in low-temperature physics. My first lab experience was working with Peter. He provided me with the cryostat I used throughout my graduate career, answered hundreds of questions, and patiently showed me the techniques I needed. Richard returned to Caltech as my thesis experiment was taking shape. He was also an excellent resource for the tricks and techniques of low-temperature physics. (Plus, he made B.O.B.2, the electrical filtering system on this cryostat). However, what helped me most was that he patiently asked hundreds of questions, which forced me to think through all the details of my experiment. It is with his help that I avoided many pitfalls.There are a number of other physicists who made significant contributions to this work. Particularly helpful were the members of the DYNAMX team from the University of New Mexico (Rob Duncan, Dimitri Sergatskov, Alex Babkin, and Steve Boyd). They provided material help with the cryo-valve system and the construction of the experimental cell. In addition, they provided a lot of expertise on performing experiments on the SOC state of 4 He. In particular, I would like to thank Rob Duncan, who served as a secondary thesis advisor during a critical time in the experiment as David Goodstein recovered from an injury. Also helpful were discussions with two theorists, Peter Weichman and Rudolf Haussmann, who helped give meaning to my results.I would like to thank my parents for many many years of encouragement and support, and not asking me too often when I was going to get my degree.I would also like to thank my wife Avital, who provided an enormous amount of support and, through an intricate dance of prodding and patience, helped guide me through this endeavor. Lastly, I thank my son Jacob, whose arrival helped destroy the illusion that maybe, just maybe, I could be a graduate student forever. We report the first results of the heat capacity of the SOC state, C ∇T , for heat fluxes 60nW/cm 2 < Q < 13 µW/cm 2 and corresponding temperatures 9 nK > T SOC − T λ > −1.1 µK. We find that C ∇T tracks the static (i.e., zero heat flux) unrounded (i.e., in zero gravity) heat capacity C 0 with two exceptions. The first is that within 250 nK of T λ , C ∇T is depressed relative to C 0 and the maximum in C ∇T is shifted to 50 nK below T λ . The second difference is that at high heat flux, C ∇T is again depressed relative to C 0 with the departure starting at about 650 nK below T λ .We present the most extensive measurements of the speed and attenuation of the SOC wave to date. We report wav...

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“…The heat capacity, C q ͑or, equivalently C Q ) in the superfluid state has also been measured. 32 To minimize the effect of gravity, the experiment was done in a cell only 0.6 mm high, so that the difference in reduced temperature from the top to the bottom of the cell was only 1ϫ10 Ϫ7 K. However, excess heat capacity over C 0 was detected only in the range tϽ5ϫ10 Ϫ7 K, so the data must be regarded to be averaged over a range of t. Nevertheless, there was an unmistakable discrepancy between theory and experiment. The excess heat capacity was found to be roughly ten times larger than could be accounted for by any theory.…”

Section: Methodsmentioning

confidence: 99%

“…34,35 There is circumstantial evidence that the DAS phenomenon may actually be caused by the physics of the interface, ͑not of the bulk helium͒ of which the singular Kapitza resistance is a symptom. 32 Finally, there is a class of experiments that actually take advantage of gravity. If, instead of the configuration shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

A dynamic new look at the lambda transition

Goodstein

Chatto

2003

American Journal of Physics

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Enhanced Heat Capacity and a New Temperature Instability in SuperfluidH4ein the Presence of a Constant Heat Flux Near

Abstract: We present the first experimental evidence that the heat capacity of superfluid 4He, at temperatures very close to the lambda point T(lambda), is enhanced by a constant heat flux Q. The heat capacity at constant Q, C(Q), is predicted to diverge at a temperature T(c)(Q) Show more

Cited by 24 publications

References 17 publications

Renormalization-group calculation of the superfluid/normal-fluid interface of liquid4He in gravity nearTλ

Renormalization-group calculation of the superfluid/normal-fluid interface of liquid4He in gravity nearTλ

Experiments on the Self-Organized Critical State of 4He

A dynamic new look at the lambda transition

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