Superfluid Project    





Research outline


Unification Project II

Unification Project I

Superfluid Project

Scientific Board


Courses by IOFPR



Earlier Events/2005

Earlier Events/2004

Earlier Events/2003

Earlier Events/2000-02

ZJ's Early Project  Proposals:

2002 VR

2001 NFR 

2001 KVA 

ZJ Unif papers 2000- 02 subs/commun.'s with Profs BJ, NA.  SS


-The QCE superfluidity mechanism (Brief Intro.)
-Selected Publications

A complete Microscopic Theory of Superfluid He II was developed by Dr. Zheng-Johansson (ZJ) since 1998, as a post doc work at the H H Wills Physics Lab., Bristol University, UK, position funded by the Swedish Natural Science Council.

The initial realization of the need for a more consistent superfuid theory, the superior confidence ZJ felt, the background knowledge,  work had benefited from many enlightening discussions with Dr J Wilson on new theory directions of superconductivity while ZJ was working on  theoretical high Tc superconductivity, a research direction introduced by Prof. B Gyorffy; the work has been conducted in a atmosphere of supports from many colleagues.

Prof. B Johansson, to whom the development of the superfluidity theory was communicated to on regular basis,  has, from the standpoint of his broad expertise in condensed matter theory,  his always-encouraging attitude toward novel unconventional approaches to physics problems which (in the following cases) lead to overall more coherent representations, given Dr ZJ unestimateable support during ZJ's development of the superfluid theory (1998-2002, and ZJ's development (basically up to final form) of the subsequent unification scheme (2000 through 2002), and (BJ) is the professor who ushered the opportunity for ZJ to do these researches.

In later 1998, Dr. Zheng-Johansson first publicly presented the theory[7] at a seminar at the Cavendish Lab, Cambridge University.

Since the development of the theory a number of international specialists in liquid helium and condensed matter physics have communicated valuable discussions over the subject, many of them have given invaluable encouragements.

One referee report from an international leading journal in the field states that "The authors include more of the underlying physics than some earlier theories, and the comparisons they make with experimental data are satisfactory.” 

Full acknowledgements in full are given in [7].


                                             *                                       The QCE Superfluidity Mechanism[1-7]:

The mechanism for the occurrence of superfluidity in He II has been a long-standing problem, and is  provided with an answer through our finding of a QCE Superfluidity MechanismIn this finding we show  from a first principles solution that the superfluidity, or frictionless flow, of He II results from a reduction in the number of phonon excitation states  N2(w) to a level which is negligibly low when the fluid is confined e.g. to a narrow channel of width d.  This results from a K quantization, being a quantum confinement effect (QCE). The critical velocity is predicted to be 

 vc (d)= [48 h c1 a/m]1/2 (1/d) 

for  d >10-5  m,  and is for lower d values reduced by a factor f=1/\sqrt{1+ (d_0/d)^u owing to fluid-wall van der Waals attraction, where c1 is first sound velocity, a interatomic spacing and $m$ $^4$He mass.  The velocity function  vc (d) agrees satisfactorily with experimental data for all $d$ values. The QCE Superfluidity Mechanism is an inseparable part of a complete consistent  Microscopic Theory of Superfluid He II [1-7] we have systematically developed  based on overall experimental observations, predicting all essential properties of He II in agreement with experiments.


Selected Publications:

[2] JX Zheng-Johansson and  B Johansson, 4 pages, "The peaked structure of phonon density of states of a confined superfluid - a theoretical prediction, ..."., ...". J. de Physique IV, France, vol.10, Dynamics in Confinement, Edited by B. Frick, Zorn and H. Büttner, Pr7-181-184, EDP Sciences, France, 2000.

[1] JX Zheng-Johansson, The Theory of Superfluidity of 4Helium, The Theory of Superfluidity of 4Helium, arXiv:cond-mat/9901125 (January 1999); booklet,  Oct, 1998, ISBN 91-630-7520-2.  

[3] JX Zheng-Johansson,  B Johansson, P-I Johansson, "Microscopic Theory of Superfluid He II," arXiv:cond-mat/0210286

[4] JX Zheng-Johansson,  B Johansson, P-I Johansson, ~30 journal pages, "The superfluidity mechanism of He II":

[5] JX Zheng-Johansson, Superfluidity of 4Helium: The Zheng-Johansson Theory, G1545012, Amer Phy Soc Bullt, 1999.

[6] JX Zheng-Johansson, "The Superfluidity Mechanism of He II",  New Developments in Superconductivity Research (with P-I Johansson),  R.W. Stevens Editor, The Nova Science Publishers, 2003. ISBN 1-59033-862-6

 [7] JX Zheng-Johansson, 230 pages, "The Microscopic Theory of Superfluid He II---With Its QCE Superfluidity Mechanism Applied to Superconductors.  Theory of Condensed Matter Expounded through the System of He II", with B Johansson, P-I Johansson,  The Nova Science Publishers Inc, New York, 2003, ISBN: 1-59033-974-6 /Link to Libraries. Collaborators B Johansson, J Wilson, et al.