Superfluid Phase Transition

2015 ◽  
pp. 99-116
Keyword(s):  
Phase Transition ◽  
Superfluid Phase

scholarly journals Renormalization group study of superfluid phase transition: Effect of compressibility

2020 ◽  
Vol 102 (2) ◽  
Author(s):  
Michal Dančo ◽  
Michal Hnatič ◽  
Tomáš Lučivjanský ◽  
Lukáš Mižišin
Keyword(s):  
Phase Transition ◽  
Renormalization Group ◽  
Superfluid Phase ◽  
Transition Effect

scholarly journals Manipulating the critical temperature for the superfluid phase transition in trapped atomic Fermi gases

2002 ◽  
Vol 65 (6) ◽  
Author(s):  
C. P. Search ◽  
H. Pu ◽  
W. Zhang ◽  
B. P. Anderson ◽  
P. Meystre
Keyword(s):  
Phase Transition ◽  
Critical Temperature ◽  
Fermi Gases ◽  
Superfluid Phase

QUANTUM CELL MODEL FOR He II AT NONZERO TEMPERATURE

1966 ◽  
Vol 44 (11) ◽  
pp. 2775-2787
Author(s):  
G. C. Knollman
Keyword(s):  
Phase Transition ◽  
Specific Volume ◽  
Cell Model ◽  
Model Development ◽  
Absolute Zero ◽  
Superfluid Transition ◽  
Superfluid Phase ◽  
Nonzero Temperature ◽  
Repulsive Energy ◽  
Zero Momentum

A previous quantum cell-model development is expanded to treat the solid-superfluid phase transition and the zero-momentum occupation at temperatures other than absolute zero. Application is made to liquid He II, which is studied at various pressures out to temperatures of about a degree absolute. The effective repulsive energy, along the solid–superfluid transition, is determined for pairs of 4He atoms localized in cells of volume equal to the specific volume.

KNOTTED VORTICES AND SUPERFLUID PHASE TRANSITION

1993 ◽  
Vol 07 (23) ◽  
pp. 1523-1526 ◽  
Author(s):  
ROBERT OWCZAREK
Keyword(s):  
Phase Transition ◽  
Ising Model ◽  
Specific Heat ◽  
Superfluid Helium ◽  
Vortex Structures ◽  
Two Dimensional ◽  
Superfluid Phase ◽  
Λ Point

In this letter, studies of knotted vortex structures in superfluid helium are continued. A model of superfluid phase transition (λ-transition) is built in this framework. Similarities of this model to the two-dimensional Ising model are shown. Dependence of specific heat of superfluid helium on temperature near the λ point is explained.

scholarly journals Spin wave theory of spin-1/2 XY model with ring exchange on a triangular lattice

2013 ◽  
Vol 91 (7) ◽  
pp. 542-547 ◽  
Author(s):  
Solomon A. Owerre
Keyword(s):  
Phase Transition ◽  
Spin Wave ◽  
Triangular Lattice ◽  
Finite Temperature ◽  
Wave Theory ◽  
Square Lattice ◽  
Xy Model ◽  
Superfluid Phase ◽  
Zero Temperature ◽  
Ring Exchange

We present the linear spin wave theory calculation of the superfluid phase of a hard-core boson J-K model with nearest neighbour exchange J and four-particle ring-exchange K at half filling on the triangular lattice, as well as the phase diagrams of the system at zero and finite temperatures. A similar analysis has been done on a square lattice (Schaffer et al. Phys. Rev. B, 80, 014503 (2009)). We find similar behaviour to that of a square lattice but with different spin wave values of the thermodynamic quantities. We also find that the pure J model (XY model), which has a well-known uniform superfluid phase with an ordered parameter [Formula: see text] at zero temperature is quickly destroyed by the inclusion of negative-K ring-exchange interactions, favouring a state with a (4π/3, 0) ordering wavevector. We further study the behaviour of the finite-temperature Kosterlitz–Thouless phase transition (TKT) in the uniform superfluid phase, by forcing the universal quantum jump condition on the finite-temperature spin wave superfluid density. We find that for K < 0, the phase boundary monotonically decreases to T = 0 at K/J = −4/3, where a phase transition is expected and TKT decreases rapidly, while for positive K, TKT reaches a maximum at some K ≠ 0. It has been shown on a square lattice using quantum Monte Carlo (QMC) simulations that for small K > 0 away from the XY point, the zero-temperature spin stiffness value of the XY model is decreased (Melko and Sandvik. Ann. Phys. 321, 1651 (2006)). Our result seems to agree with this trend found in QMC simulations for two-dimensional systems.

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