The density maximum in liquid He4 and its relationship to the lambda point

Deeney, F.A.; O'Leary, J P; O'Sullivan, P.

doi:10.1016/j.physleta.2006.04.111

Cited by 6 publications

(6 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a recent communication [22] we showed that the existence of the density maximum in liquid He 4 could be explained in terms of this ZPE effect acting in opposition to the classical expansion/contraction. Specifically, as the temperature falls, more and more helium atoms drop into the ground state, causing the fluctuations in kinetic energy K to increase and hence the system to expand.…”

mentioning

confidence: 89%

Zero point energy and the origin of the density maximum in water

Deeney

O'Leary

2008

Physics Letters A

Self Cite

View full text Add to dashboard Cite

mentioning

confidence: 89%

Zero point energy and the origin of the density maximum in water

Deeney

O'Leary

2008

Physics Letters A

Self Cite

View full text Add to dashboard Cite

“…Recently, Deeney et al [8] showed that a quantum source of energy leading to the expansion of the condensate may explain the negative dT λ /dP behavior. The SQHA model supports this hypothesis showing that the quantum pseudo potential (QPP) (that acts only in the quantum condensed state) generate a repulsive force leading to the anomalous behavior at lambda point.…”

Section: Shortly Afterwards Termentioning

confidence: 99%

“…Moreover, given dT c /dP ~ d∆T c /dP it follows that dT c /dP ∝ a n 2 d(V −2 )/dP > 0 (8) since V decreases with the pressure. Feyman [4] in 1953 and later Butler and Friedman [5,6] calculated in detail the contribution of the inter-molecular potential for a bosonic system showing that it would need a repulsive potential, causing an expansion of the gas, in order to lower T B as one might expect from (7) (i.e., ∆T c < 0 ).…”

Section: Introductionmentioning

confidence: 99%

The Quantum Potential: The Missing Interaction in the Density Maximum of He4 at the Lambda Point

Chiarelli¹

2013

AJPC

View full text Add to dashboard Cite

The lambda point in liquid He 4 is a well established phenomenon acknowledged as an example of Bose-Einstain condensation. This is generally accepted, but there are serious discrepancies between the theory and experimental results, namely the lower value of the transition temperature T λ and the negative value of dT λ /dP. These discrepancies can be explained in term of the quantum stochastic hydrodynamic analogy (SQHA). The SQHA shows that at the He 4 I →He 4 II superfluid transition the quantum coherence length λ c becomes of order of the distance up to which the wave function of a couple of He 4 atoms extends itself. In this case, the He 4 2 state is quantum and the quantum pseudo-potential brings a repulsive interaction that leads to the negative dT λ /dP behavior. This fact overcomes the difficulty to explain the phenomenon by introducing a Hamiltonian inter-atomic repulsive potential that would obstacle the gas-liquid transition.

show abstract

“…We have already commented upon this in a general way elsewhere [6]. There we noted that liquid 4 He is a particularly simple liquid, in that its atoms are spherically symmetrical and the interatomic forces are purely van der Waals' in nature.…”

Section: Density Maximum In Liquid 4 Hementioning

confidence: 85%