09.02.2018 Views

978-1-940366-36-4_WholeBook

Boris V. Vasiliev Supercondustivity Superfluidity

Boris V. Vasiliev
Supercondustivity Superfluidity

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Chapter 7 The Condensate of Zero-Point Oscillations and Type-I Superconductors<br />

Two electron pairs at an in-phase oscillations have a high energy of interaction and<br />

therefore cannot form the condensate. The condensate can be formed only by the particles<br />

that make up the difference between the populations of levels N 0 −N 1 . In a dimensionless<br />

form, this difference defines the order parameter:<br />

Ψ =<br />

N 0 N 1<br />

− . (7.5)<br />

N 0 + N 1 N 0 + N 1<br />

In the theory of superconductivity, by definition, the order parameter is determined by<br />

the value of the energy gap<br />

Ψ = ∆ T /∆ 0 . (7.6)<br />

When taking a counting of energy from the level ε 0 , we obtain<br />

∆ T<br />

∆ 0<br />

= N 0 − N 1<br />

N 0 + N 1<br />

≃ e2∆ T /kT − 1<br />

e 2∆ T /kT<br />

+ 1 = th(2∆ T /kT ). (7.7)<br />

Passing to dimensionless variables δ ≡ ∆ T<br />

∆ 0<br />

, t ≡ kT<br />

kT c<br />

and β ≡ 2∆0<br />

kT c<br />

we have<br />

δ = eβδ/t − 1<br />

= th(βδ/t). (7.8)<br />

e βδ/t + 1<br />

This equation describes the temperature dependence of the energy gap in the spectrum<br />

of zero-point oscillations. It is similar to other equations describing other physical<br />

phenomena, that are also characterized by the existence of the temperature dependence<br />

of order parameters [43], [44]. For example, this dependence is similar to temperature<br />

dependencies of the concentration of the superfluid component in liquid helium or the<br />

spontaneous magnetization of ferromagnetic materials. This equation is the same for all<br />

order-disorder transitions (the phase transitions of 2nd-type in the Landau classification).<br />

The solution of this equation, obtained by the iteration method, is shown in Figure 7.2.<br />

Science Publishing Group 79

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!