Josephson relations

Ideally a standard cell is constmcted simply and is characterized by a high constancy of emf, a low temperature coefficient of emf, and an emf close to one volt. The Weston cell, which uses a standard cadmium sulfate electrolyte and electrodes of cadmium amalgam and a paste of mercury and mercurous sulfate, essentially meets these conditions. The voltage of the cell is 1.0183 V at 20°C. The a-c Josephson effect, which relates the frequency of a superconducting oscillator to the potential difference between two superconducting components, is used by NIST to maintain the unit of emf. The definition of the volt, however, remains as the Q/A derivation described. 

The property of the spin-triplet components fi,2,z un) = — /i,2,3(—w ) means that their presence is not easy to observe. For example, the order parameter A is related to the sum X n=-oo /(wn) in which all contributions of the odd functions f 1,2,3 cancel. However, there are phenomena where the presence of the spin-triplet pairing plays a crucial role. One of them is the effect of the Tc dependence on the mutual orientation of magnetizations in the F/S/F structure. Another one is the predicted long-range proximity effect based on the spin-triplet component, which should lead to a Josephson current in F/S/F/S structures with anomalously thick F-layers.[10] The latter is relevant for experimental results of Ref. [5]. 

The Josephson current, being an equilibrium supercurrent between two superconductors, can be calculated from the general thermodynamical relation... 

We found out that interlayer tunneling I-V characteristics at low temperatures essentially differ from those of conventional Josephson junctions between s-wave superconductors. We specify [14] 1) Jc(0) is strongly reduced to compare with the value expected from Ambegaokar-Baratoff (A-B) relation, J(U1 (0) = KO nAa / 2es 2) quadratic and scaling behaviour of [Pg.185]

It is practically impossible to prepare a stable HTSC material for which all the desired characteristics are present simultaneously. However, in specific applications, only a few of the above-mentioned characteristics are usually important. Moreover, advantage can be taken of certain effects which lead normally to unwanted characteristics of HTSC materials, for special purposes. For example, when the grain boundaries have microscopic areas with low conductivity, it is possible in certain cases to realize the Josephson and related effects. 

The last two papers are also related to quantum computing issues, in particular the characterization of various kinds of qubits based on Josephson junctions. 

When 7 exceeds 7, a constant phase difference can no longer be maintained and a voltage develops across the junction. The phases on the two sides of the junction begin to slip with respect to each other, with the rate of slippage governed by the Josephson voltage-phase relation... 

The system in Example 6.6.3 is closely related to a model of two superconducting Josephson junctions coupled through a resistive load (Tsang et al. 1991). For further discussion, see Exercise 6.6.9 and Example 8.7.4. Reversible, nonconservative systems also arise in the context of lasers (Politi et al. 1986) and fluid flows (Stone, Nadim, and Strogatz 1991 and Exercise 6.6.8). 

The Josephson effect is the phenomenon in which two superconducting materials weakly coupled through a non-superconducting interface show a sharp increase in conductance of current flowing from one of the superconductors to the other if radiation of a suitable frequency is applied to the interface. The relation between the voltage difference between the two superconductors Uj and the frequency / of the applied radiation for which there is an increase in current is given by... 

The microstructure of YBa2Cu30y thin films and related heterostructures, which are the basis for several types of edge-based Josephson junction were investigated by high-resolution transmission electron microscopy. The results show that the microstructure, interfaces, grain boundaries and defect configurations in these films are strongly influenced by the substrate and the often complex structure of the film surfaces on which the subsequent layers are deposited. 

Almendral JM, Rosenthal ME, Stamato NJ, Marchlinski FE, Buxton AE, Frame LH, Miller JM, Josephson ME. Analysis of the resetting phenomenon in sustained uniform ventricular tachycardia incidence and relation to termination. J Am Coll Cardiol 1986 8 294-300. 

The optical activity of bile acids and their sodium salts depends on their purity, the wavelength of light employed, the solvent, and the concentration. The values given in standard references (27, 74) are often not comparable. Josephson (75) showed that increased concentration of bile salts in water substantially decreases the optical activity. The concentration, however, made little difference if the salts were studied in alcohol. Since the bile salts do not form micelles in alcohol (unpublished observations by the author), the variations noted in water may be related to the formation of micelles. The optical rotation of the acids in other organic solvents is not affected appreciably by concentration. The reader is referred to the earlier work of Sobotka (28) and Josephson (75). 

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