Breakdown of Fourier's Law near the Superfluid Transition in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">He</mml:mi></mml:math>

Day, Peter; Moeur, W. A.; McCready, S. S.; Sergatskov, Dmitri; Liu, Feng Chuan; Duncan, R. V.

doi:10.1103/physrevlett.81.2474

Cited by 30 publications

(16 citation statements)

References 23 publications

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“…For very low heat currents Q ≤ 40 nW/cm 2 the data of Day et al 33 indicate that the thermal resistivity ρ T = 1/λ T (∆T, Q) is a smooth function of ∆T in the limit Q → 0 if gravity is present. This fact means that gravity prevents the system from reaching the critical point of the superfluid transition, so that all physical quantities are smooth and nonsingular near T λ .…”

Section: Influence Of Gravitymentioning

confidence: 99%

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Liquid4Henear the superfluid transition in the presence of a heat current and gravity

Haussmann¹

1999

Phys. Rev. B

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The effects of a heat current and gravity in liquid 4 He near the superfluid transition are investigated for temperatures above and below T λ . We present a renormalization-group calculation based on model F for the Green's function in a self-consistent approximation which in quantum manyparticle theory is known as the Hartree approximation. The approach can handle the average order parameter ψ = 0 above and below T λ and includes effects of vortices. We calculate the thermal conductivity λT(∆T, Q) and the specific heat C(∆T, Q) for all temperature differences ∆T = T −T λ and heat currents Q in the critical regime. Furthermore, we calculate the temperature profile T (z). Below T λ we find a second correlation length ξ1 ∼ Q −1 (T λ − T ) +ν which describes the dephasing of the order-parameter field due to vortices. We find dissipation and mutual friction of the superfluidnormal fluid counterflow and calculate the Gorter-Mellink coefficient A. We compare our theoretical results with recent experiments.

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Section: Influence Of Gravitymentioning

confidence: 99%

“…Day et al 33 investigated the superfluid-normal-fluid interface in 4 He and measured the thermal conductivity λ T for very small heat currents Q in the interval 20 nW/cm 2 < Q < 6 µW/cm 2 . The heat current flows upwards so that the gradient ∂ z T λ is positive.…”

Section: Influence Of Gravitymentioning

confidence: 99%

Liquid4Henear the superfluid transition in the presence of a heat current and gravity

Haussmann¹

1999

Phys. Rev. B

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“…2 2 In this instance, we have actually defined T C (Q) as the temperature where κ diverges. A previous experiment in a "heat-from-below" configuration found that κ diverges at a temperature T C (Q) < T λ but that the transition was rounded [6]. They hypothesized that the rounding was due to a maximum possible size of correlated fluctuations caused by the gravity induced gradient in T λ .…”

Section: The Soc Statementioning

confidence: 99%

“…In addition, the model does not accurately predict the temperature profile in the crossover region between superfluid and SOC state, so the calculation, while instructive, is not suitable for numerical predictions. 6 In sec. 3.11, we made the determination that the bubble chamber is not thermally connected to the main chamber of helium.…”

Section: The Uncorrected 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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“…These devices have been used to explore new effects within quantum liquids on the ground, such as the elucidation of the self-organized heat-flow state [3], the mapping of the nonlinear heat-transport region [4], and the detection of new diffusion waves [5], all near the superfluid transition in 4 He. A detailed report of these new devices, including a first-principles analysis of their noise performance, has been published previously [6].…”

Section: Introductionmentioning

confidence: 99%

New Paramagnetic Susceptibility Thermometers for Fundamental Physics Measurements

Sergatskov¹,

Day

Бабкин³

et al. 2003

AIP Conference Proceedings

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Abstract. New paramagnetic susceptibility thermometers have been developed for use in fundamental physics missions in earth orbit. These devices use a SQUID magnetometer to measure the variation in the dc magnetization of a thermometric element that consists of a dilute concentration of manganese in a palladium matrix. Near 2.2 K these new PdMn thermometers have demonstrated a temperature resolution of better than 100 pK/ Hz and a time constant of 50 ms when operated with a 50 K/W thermal resistance to the liquid helium sample. These thermometers have been observed to be remarkably stable, with a drift of less than 10 fK/s. The observed power spectral density of the noise from these thermometers is consistent with separate measurements of the device's time constant and thermal standoff from the bath. Recently these PdMn materials have been made into thin films and microstructures for use in future studies of quantum liquids, and for possible use in a new class of bolometers and radiometers. These thermometers have been integrated into an experimental cell and thermal isolation network that are adequate to keep stray heats stable to within a few picowatts, with no systematic temperature errors greater than 60 pK, over the course of a planned fundamental physics experiment on Earth orbit.

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Breakdown of Fourier's Law near the Superfluid Transition in4He

Cited by 30 publications

References 23 publications

Liquid4Henear the superfluid transition in the presence of a heat current and gravity

Liquid4Henear the superfluid transition in the presence of a heat current and gravity

Experiments on the Self-Organized Critical State of 4He

New Paramagnetic Susceptibility Thermometers for Fundamental Physics Measurements

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