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We further develop a theory of self-resonance after inflation in a large class of models involving multiple scalar fields. We concentrate on inflaton potentials that carry an internal symmetry, but also analyze weak breaking of this symmetry. This is the second part of a two part series of papers. Here in Part 2 we develop an understanding of the resonance structure from the underlying many particle quantum mechanics. We begin by a small amplitude analysis, which obtains the central resonant wave numbers, and relate it to perturbative processes. We show that the dominant resonance structure is determined by (i) the nonrelativistic scattering of many quantum particles and (ii) the application of Bose-Einstein statistics to the adiabatic and isocurvature modes, as introduced in Part 1 [1]. Other resonance structure is understood in terms of annihilations and decays. We setup Bunch-Davies vacuum initial conditions during inflation and track the evolution of modes including Hubble expansion. In the case of a complex inflaton carrying an internal U(1) symmetry, we show that when the isocurvature instability is active, the inflaton fragments into separate regions of \phi-particles and anti-\phi-particles. We then introduce a weak breaking of the U(1) symmetry; this can lead to baryogenesis, as shown by some of us recently [2,3]. Then using our results, we compute corrections to the particle-antiparticle asymmetry from this preheating era.

We develop a theory of self-resonance after inflation. We study a large class of models involving multiple scalar fields with an internal symmetry. For illustration, we often specialize to dimension-four potentials, but we derive results for general potentials. This is the first part of a two part series of papers. Here in part 1 we especially focus on the behavior of long-wavelength modes, which are found to govern most of the important physics. Since the inflaton background spontaneously breaks the time-translation symmetry and the internal symmetry, we obtain Goldstone modes; these are the adiabatic and isocurvature modes. We find general conditions on the potential for when a large instability band exists for these modes at long wavelengths. For the adiabatic mode, this is determined by a sound speed derived from the time-averaged potential, while for the isocurvature mode, this is determined by a speed derived from a time-averaged auxiliary potential. Interestingly, we find that this instability band usually exists for one of these classes of modes, rather than both simultaneously. We focus on backgrounds that evolve radially in field space, as set up by inflation, and also mention circular orbits, as relevant to $Q$-balls. In part 2 [M. P. Hertzberg et al., Phys. Rev. D 90, 123529 (2014)] we derive the central behavior from the underlying description of many-particle quantum mechanics, and introduce a weak breaking of the symmetry to study corrections to particle-antiparticle production from preheating.

Previously, five phonon energies were used to explain 16 peaks in the measured lattice absorption spectrum of GaAs. It is shown here that the five phonon energies are not unique and that a different set of values is also compatible with the available infrared data both with respect to the absorption peak positions and the temperature dependence of the absorption. A similar difficulty is also noted for some previously published work on CdS. It is suggested that difference band absorption measurements might show which sets of phonon energies are correct.

Two methods are described for the measurement of lifetime of minority carriers. One depends on pulse injection of carriers in a filament and detection, after a known time, at a collector. The second makes use of the decay of the conductivity modulation caused by minority carriers after injection at a single contact. Both measure the lifetime in a small region rather than the average value over a large part of the sample.