Sidebar 21.SB2: A two-phase solution of the
Kadomtsev–Petviashvili equation (21.9.3)
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►A two-phase solution of the Kadomtsev–Petviashvili equation (21.9.3).
Such a solution is given in terms of a Riemann theta function with two phases.
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►In Figure 36.3.13(a) points of confluence of phase contours are zeros of ; similarly for other contour plots in this subsection.
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Figure 36.3.13: Phase of Pearcey integral .
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Figure 36.3.14: Density plots of phase of swallowtail canonical integrals.
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Figure 36.3.21: Phase of hyperbolic umbilic canonical integral .
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►By painting the surfaces with a color that encodes the phase, , both the magnitude and phase of complex valued functions can be displayed.
We offer two options for encoding the phase.
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►The color encoded phases of (above) and (below), are constrasted in the negative half of the complex plane.
►In the upper half of the image, the poles of are clearly visible at negative integer values of : the phase changes by around each pole, showing a full revolution of the color wheel.
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►Phase changes around the zeros are of opposite sign to those around the poles.
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►See Armitage (1989), Berry and Keating (1998, 1999), Keating (1993, 1999), and Sarnak (1999).
►The zeta function arises in the calculation of the partition function of ideal quantum gases (both Bose–Einstein and Fermi–Dirac cases), and it determines the critical gas temperature and density for the Bose–Einstein condensation phase transition in a dilute gas (Lifshitz and Pitaevskiĭ (1980)).
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