Quantum depinning of flux lines from columnar defects

Dissipative macroscopic quantum tunneling in type-I superconductors

“…Then equations (27) and (40) with conditions S ef f ∼ 30 and T c ∼ 1K give a/p 1/3 ∼ 3.7 nm and √ ǫa ∼ 0.25 nm. Note that these relations are specific for a two-dimensional elastic manifold pinned by a two-dimensional layer.…”

“…Finally, we apply a rescaling ofû n by a factor (2π) 3/2 λ n to obtain the instanton solution. This procedure leads to 27) with numerical value of the integral I 0 = 531 ± 19. This somewhat surprisingly large value of the integral has been confirmed by our use of different computational grids.…”

“…Firstly the dimensionless effective action of Eq. (27), which is the WKB exponent of the tunneling rate, should not exceed 30 − 40 in order for the tunneling to occur on a reasonable time scale. Secondly, the crossover temperature determined by Eq.…”

“…1. Somewhat similar problems in 1+1 dimensions have been studied for a flux line pinned by the interlayer atomic potential in a layered superconductor 11 , for a flux line pinned by a columnar defect 27 , and for fractional vortices in long Josephson junctions 15 . However, the two-dimensional nature of the interface, as compared to a one-dimensional flux line, makes the interface problem more challenging.…”

Thermally assisted quantum cavitation in solutions of 3 He in 4 He

“…Let us first generalize the functional-integral approach as used in [3], to the mixture case (see also [13] for another example of how it applies). We recall that above a crossover temperature T * , the cavitation rate, i.e., the number of bubbles formed per unit time and volume, is given by…”